2021 in archosaur paleontology

• A study on the phylogenetic relationships of pseudosuchian archosaurs, aiming to determine drivers of body size evolution in this group, is published by Stockdale & Benton (2021);{{cite journal | vauthors = Stockdale MT, Benton MJ | title = Environmental drivers of body size evolution in crocodile-line archosaurs | journal = Communications Biology | volume = 4 | issue = 1 | pages = 38 | date = January 2021 | pmid = 33414557 | pmc = 7790829 | doi = 10.1038/s42003-020-01561-5 }} the study is subsequently criticized by Benson et al. (2022).{{cite journal | vauthors = Benson RB, Godoy P, Bronzati M, Butler RJ, Gearty W | title = Reconstructed evolutionary patterns for crocodile-line archosaurs demonstrate impact of failure to log-transform body size data | journal = Communications Biology | volume = 5 | issue = 1 | pages = Article 171 | year = 2022 | doi = 10.1038/s42003-022-03071-y | pmid = 35217775 | pmc = 8881462 |doi-access=free }}{{cite journal | vauthors = Stockdale MT, Benton MJ | title = Reply to: 'Reconstructed evolutionary patterns from crocodile-line archosaurs demonstrate the impact of failure to log-transform body size data' | journal = Communications Biology | volume = 5 | issue = 1 | pages = Article 170 | year = 2022 | doi = 10.1038/s42003-022-03072-x | pmid = 35217770 | pmc = 8881626 |doi-access=free }}
• The first occurrence of the track type "Chirotherium" lulli (inferred to be produced by a pseudosuchian archosaur) from western North America is reported from the Owl Rock Member of the Chinle Formation (Utah, United States) by Milner et al. (2021).{{cite journal| vauthors = Milner AR, Irmis RB, Lockley MG, Klein H, Slauf D, Romillio A |title=First report of "Chirotherium" lulli from the Upper Triassic Chinle Formation of San Juan County, Utah |year=2021 |journal=New Mexico Museum of Natural History and Science Bulletin |volume=82 |pages=275–284 |url=https://www.researchgate.net/publication/348009876 }}
• A study on the skeletal anatomy and phylogenetic relationships of Revueltosaurus callenderi is published by Parker et al. (2021).{{cite journal | vauthors = Parker WG, Nesbitt SJ, Irmis RB, Martz JW, Marsh AD, Brown MA, Stocker MR, Werning S | title = Osteology and relationships of Revueltosaurus callenderi (Archosauria: Suchia) from the Upper Triassic (Norian) Chinle Formation of Petrified Forest National Park, Arizona, United States | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2353–2414 | doi = 10.1002/ar.24757 | pmid = 34585850 | pmc = 9544919 |doi-access=free }}
• A study on the skull anatomy and likely feeding habits of Effigia okeeffeae is published by Bestwick et al. (2021).{{cite journal | vauthors = Bestwick J, Jones AS, Nesbitt SJ, Lautenschlager S, Rayfield EJ, Cuff AR, Button DJ, Barrett PM, Porro LB, Butler RJ | title = Cranial functional morphology of the pseudosuchian Effigia and implications for its ecological role in the Triassic | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2435–2462 | doi = 10.1002/ar.24827 | pmid = 34841701 | s2cid = 244713889 | url = https://discovery.ucl.ac.uk/id/eprint/10141645/ | url-access = subscription }}

• Description of the braincase of Aetosauroides scagliai, based on data from specimens from the Upper Triassic Candelária Sequence (Brazil), is published by Paes Neto et al. (2021).{{cite journal| vauthors = Paes Neto VD, Desojo JB, Brust AC, Ribeiro AM, Schultz CL, Soares MB |year=2021 |title=The first braincase of the basal aetosaur Aetosauroides scagliai (Archosauria: Pseudosuchia) from the Upper Triassic of Brazil |journal=Journal of Vertebrate Paleontology |volume=41 |issue=2 |pages=e1928681 |doi=10.1080/02724634.2021.1928681 |bibcode=2021JVPal..41E8681P |s2cid=237518035 }}
• Description of the skull Aetosauroides scagliai, and a study on the likely diet and paleobiology of this aetosaur, is published by Paes Neto et al. (2021).{{cite journal| vauthors = Paes Neto VD, Desojo JB, Brust AC, Ribeiro AM, Schultz CL, Soares MB |title=Skull osteology of Aetosauroides scagliai Casamiquela, 1960 (Archosauria: Aetosauria) from the Late Triassic of Brazil: New insights into the paleobiology of aetosaurs |year=2021 |journal=Palaeontologia Electronica |volume=24 |issue=3 |pages=Article number 24.3.a33 |doi=10.26879/1120 |doi-access=free }}
• A study on the anatomy of the axial skeleton of Aetosauroides is published by Paes-Neto et al. (2021), who propose that Polesinesuchus aurelioi is a junior synonym of Aetosauroides scagliai.{{cite journal | vauthors = Paes-Neto VD, Desojo JB, Brust AC, Schultz CL, Da-Rosa ÁA, Soares MB | title = Intraspecific variation in the axial skeleton of Aetosauroides scagliai (Archosauria: Aetosauria) and its implications for the aetosaur diversity of the Late Triassic of Brazil | journal = Anais da Academia Brasileira de Ciências | volume = 93 | issue = suppl 2 | pages = e20201239 | year = 2021 | doi = 10.1590/0001-3765202120201239 | pmid = 34468486 | hdl = 11336/150258 | s2cid = 237372648 | url = https://www.scielo.br/j/aabc/a/XqCg3ZtjR9DwXbrz85KbJDQ/?lang=en | hdl-access = free }}
• An incomplete, largely articulated postcranial skeleton of a basal aetosaur, possibly distinct from Aetosauroides scagliai, and preserving anatomical features which aren't often preserved in aetosaur specimens (including extensive appendicular armor and a well-preserved caudal ventral carapace), is described from the Upper Triassic Ischigualasto Formation (Argentina) by Hecket, Martínez & Celeskey (2021).{{cite journal| vauthors = Heckert AB, Martínez RN, Celeskey MD |year=2021 |title=Anatomical details of Aetosauria (Archosauria:Pseudosuchia) as revealed by an articulated posterior skeleton from the Upper Triassic Ischigualasto Formation, San Juan Province, Argentina |journal=Ameghiniana |volume=58 |issue=6 |pages=464–484 |doi=10.5710/AMGH.05.09.2021.3426 |s2cid=239751891 }}
• An osteoderm of Typothorax coccinarum with punctures and scores which are likely bite marks is described from the Upper Triassic Chinle Formation (Arizona, United States) by Drymala, Bader & Parker (2021), who interpret this finding as supporting the hypothesis that aetosaurs were prey items of large archosauromorphs.{{cite journal | vauthors = Drymala SM, Bader K, Parker WG |year=2021 |title=Bite marks on an aetosaur (Archosauria, Suchia) osteoderm: assessing Late Triassic predator-prey ecology through ichnology and tooth morphology |journal=PALAIOS |volume=36 |issue=1 |pages=28–37 |doi=10.2110/palo.2020.043 |bibcode=2021Palai..36...28D |s2cid=231857816 }}
• Reyes, Parker & Marsh (2021) describe the first complete articulated skull of Typothorax coccinarum from the Owl Rock Member of the Chinle Formation (Petrified Forest National Park), and evaluate the implications of this specimen for the knowledge of the relationships and morphological diversity of aetosaurs.{{cite journal| vauthors = Reyes WA, Parker WG, Marsh AD |year=2021 |title=Cranial Anatomy and Dentition of the Aetosaur Typothorax coccinarum (Archosauria: Pseudosuchia) from the Upper Triassic (Revueltian–Mid Norian) Chinle Formation of Arizona |journal=Journal of Vertebrate Paleontology |volume=40 |issue=6 |pages=e1876080 |doi=10.1080/02724634.2020.1876080 |s2cid=233616969 }}
• A study on the biomechanical properties of the skull of Neoaetosauroides engaeus is published by Taborda, Desojo & Dvorkin (2021).{{cite journal| vauthors = Taborda JR, Desojo JB, Dvorkin EN |year=2021 |title=Biomechanical skull analysis of an aetosaur Neoaetosauroides engaeus using finite element analysis |journal=Ameghiniana |volume=58 |issue=5 |pages=401–415 |doi=10.5710/AMGH.23.07.2021.3412 |url=https://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/3412 |s2cid=238018422 |url-access=subscription }}
• Revision of isolated braincases of Desmatosuchus from the Placerias Quarry locality in the Chinle Formation (Arizona, United States) is published by von Baczko et al. (2021), who report the presence of two species of Desmatosuchus (D. spurensis and D. smalli) at the Placerias Quarry.{{cite journal | vauthors = von Baczko MB, Desojo JB, Gower DJ, Ridgely R, Bona P, Witmer LM | title = New digital braincase endocasts of two species of Desmatosuchus and neurocranial diversity within Aetosauria (Archosauria: Pseudosuchia) | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2415–2434 | doi = 10.1002/ar.24798 | pmid = 34662509 | hdl = 11336/152847 | s2cid = 239026663 | hdl-access = free }}

• A study on the morphological diversity of skull and jaw shape in crocodylomorphs throughout their evolutionary history is published by Stubbs et al. (2021).{{cite journal | vauthors = Stubbs TL, Pierce SE, Elsler A, Anderson PS, Rayfield EJ, Benton MJ | title = Ecological opportunity and the rise and fall of crocodylomorph evolutionary innovation | journal = Proceedings. Biological Sciences | volume = 288 | issue = 1947 | pages = 20210069 | date = March 2021 | pmid = 33757349 | pmc = 8059953 | doi = 10.1098/rspb.2021.0069 | s2cid = 232326789 }}
• A study on the evolution of the skull morphology in crocodyliforms is published by Felice, Pol & Goswami (2021).{{cite journal | vauthors = Felice RN, Pol D, Goswami A | title = Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 288 | issue = 1954 | pages = Article ID 20210919 | year = 2021 | pmid = 34256005 | pmc = 8277476 | doi = 10.1098/rspb.2021.0919 }}
• A study on the anatomy, phylogenetic relationships and stratigraphy of the holotype specimen of Notochampsa istedana is published by Dollman et al. (2021).{{cite journal| vauthors = Dollman KN, Clark JM, Viglietti PA, Browning C, Choiniere JN |title=Revised anatomy, taxonomy and biostratigraphy of Notochampsa istedana Broom, 1904, a Lower Jurassic crocodyliform from the Clarens Formation (Stormberg Group), and its implications for early crocodyliform phylogeny |year=2021 |journal=Journal of Systematic Palaeontology |volume=19 |issue=9 |pages=651–675 |doi=10.1080/14772019.2021.1948926 |bibcode=2021JSPal..19..651D |s2cid=238241175 }}
• A study on the skull anatomy and phylogenetic placement of Eopneumatosuchus colberti is published by Melstrom, Turner & Irmis (2021).{{cite journal | vauthors = Melstrom KM, Turner AH, Irmis RB | title = Reevaluation of the cranial osteology and phylogenetic position of the early crocodyliform Eopneumatosuchus colberti, with an emphasis on its endocranial anatomy | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2557–2582 | doi = 10.1002/ar.24777 | pmid = 34679248 | s2cid = 239473004 | doi-access = free }}
• A study on the bite force in mesoeucrocodylians throughout their evolutionary history is published by Gignac, Smaers & O'Brien (2021).{{cite journal | vauthors = Gignac PM, Smaers JB, O'Brien HD | title = Unexpected bite-force conservatism as a stable performance foundation across mesoeucrocodylian historical diversity | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2823–2837 | doi = 10.1002/ar.24768 | pmid = 34555273 | s2cid = 237615910 }}
• A study on feeding habits of notosuchians from the Upper Cretaceous Bauru Group (Brazil), as indicated by stable carbon and oxygen isotope data from tissues of notosuchians from two sites from Bauru Group, is published by Klock et al. (2021).{{cite journal | vauthors = Klock C, Leuzinger L, Santucci RM, Martinelli AG, Marconato A, Marinho TS, Luz Z, Vennemann T | title = A bone to pick: stable isotope compositions as tracers of food sources and paleoecology for notosuchians in the Brazilian Upper Cretaceous Bauru Group | journal = Cretaceous Research | volume = 131 | pages = Article 105113 | year = 2021 | doi = 10.1016/j.cretres.2021.105113 | s2cid = 263326282 }}
• Description of coprolites from the Upper Cretaceous Adamantina Formation (Brazil) found in association with skeletons of baurusuchid and sphagesaurid crocodylomorphs, and a study on the implications of these coprolites for the knowledge of the diet of these crocodylomorphs, is published by de Oliveira et al. (2021).{{cite journal | vauthors = de Oliveira FA, Santucci RM, de Oliveira CE, de Andrade MB | title = Morphological and compositional analyses of coprolites from the Upper Cretaceous Bauru Group reveal dietary habits of notosuchian fauna | journal = Lethaia | volume = 54 |issue=5 |pages=664–686 | year = 2021 | doi = 10.1111/let.12431 | bibcode = 2021Letha..54..664D | s2cid = 236299609 }}
• A study on the morphological variation in the dentition of uruguaysuchid crocodylomorphs is published by Figueiredo & Kellner (2021).{{cite journal | vauthors = Figueiredo RG, Kellner AW | title = Morphological variation in the dentition of Uruguaysuchidae (Crocodyliformes: Notosuchia) | journal = Anais da Academia Brasileira de Ciências | volume = 93 | issue = suppl 2 | pages = e20201594 | year = 2021 | doi = 10.1590/0001-3765202120201594 | doi-broken-date = 11 January 2025 | pmid = 34406219 | s2cid = 237197248 | url = https://www.scielo.br/j/aabc/a/B4gmKXhxh5rkqZdYrXypnDL/abstract/?lang=en | url-access = subscription }}
• A study on the bone histology and growth dynamics of Araripesuchus, based on data from specimens from the La Buitrera Palaeontological Area (Río Negro Province, Argentina), is published by Fernández Dumont et al. (2021).{{cite journal | vauthors = Fernández Dumont ML, Pereyra ME, Bona P, Apesteguía S | title = New data on the palaeosteohistology and growth dynamic of the notosuchian Araripesuchus Price, 1959 | journal = Lethaia | volume = 54 | issue = 4 | pages = 578–590 | year = 2021 | doi = 10.1111/let.12423 | bibcode = 2021Letha..54..578F }}
• A study on the resistance to stress of the skull of Araripesuchus gomesii, and on its implications for the knowledge of likely diet of this crocodylomorph, is published by Nieto et al. (2021).{{cite journal | vauthors = Nieto MN, Degrange FJ, Sellers KC, Pol D, Holliday CM | title = Biomechanical performance of the cranio-mandibular complex of the small notosuchian Araripesuchus gomesii (Notosuchia, Uruguaysuchidae) | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2695–2707 | doi = 10.1002/ar.24697 | pmid = 34132040 | s2cid = 235450781 }}
• New partially preserved skull of Campinasuchus dinizi is described from the Fazenda São José (Adamantina/Vale do Rio do Peixe Formation, Brazil) by Darlim et al. (2021), who evaluate the implications of this specimen for the knowledge of the distribution of baurusuchids in the Late Cretaceous of South America.{{cite journal | vauthors = Darlim G, Carvalho IS, Tavares SA, Langer MC | title = A new Pissarrachampsinae specimen from the Bauru Basin, Brazil, adds data to the understanding of the Baurusuchidae (Mesoeucrocodylia, Notosuchia) distribution in the Late Cretaceous of South America | journal = Cretaceous Research | volume = 128 | pages = Article 104969 | year = 2021 | doi = 10.1016/j.cretres.2021.104969| bibcode = 2021CrRes.12804969D |issn=0195-6671 }}
• The first known baurusuchid yearling is described from the Adamantina Formation (Brazil) by dos Santos et al. (2021).{{cite journal| vauthors = dos Santos DM, Santucci RM, de Oliveira CE, de Andrade MB |title=A baurusuchid yearling (Mesoeucrocodylia, Crocodyliformes), from the Adamantina Formation, Bauru Group, Upper Cretaceous of Brazil |journal=Historical Biology |year=2022 |volume=34 |issue=11 |pages=2137–2151 |doi=10.1080/08912963.2021.2001807 |bibcode=2022HBio...34.2137M |s2cid=245345923 }}
• New baurusuchid specimen, providing new information on the skeletal growth in baurusuchids, is described from the Upper Cretaceous Adamantina Formation (Brazil) by Marchetti et al. (2021).{{cite journal| vauthors = Marchetti I, Delcourt R, Tavares SA, Canalli JF, Nascimento PM, Ricardi-Branco F |title=Morphological and paleohistological description of a new Baurusuchidae specimen from the Adamantina Formation, Upper Cretaceous of Brazil |year=2021 |journal=Journal of South American Earth Sciences |volume=114 |pages=Article 103693 |doi=10.1016/j.jsames.2021.103693 |s2cid=245546220 }}
• A study on the anatomy of the endocranial structures of Zulmasuchus querejazus, and on its implications for the knowledge of the head posture, hearing capabilities and likely lifestyle of this sebecid, is published by Pochat-Cottilloux et al. (2021).{{cite journal | vauthors = Pochat-Cottilloux Y, Martin JE, Jouve S, Perrichon G, Adrien J, Salaviale C, de Muizon C, Cespedes R, Amiot R | title = The neuroanatomy of Zulmasuchus querejazus (Crocodylomorpha, Sebecidae) and its implications for the paleoecology of sebecosuchians | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2708–2728 | doi = 10.1002/ar.24826 | pmid = 34825786 | s2cid = 244660946 | url = https://hal.archives-ouvertes.fr/hal-03456766/file/AR-21-0290_Proof_hi.pdf }}
• New soft tissue records for thalattosuchians are reported from the Late Jurassic localities of Wattendorf and Painten (Bavaria, Germany) by Spindler et al. (2021), who interpret their findings as indicating the skin of metriorhynchids lacked any traces of scales or scutes and instead showed folded and transverse fibers.{{cite journal| vauthors = Spindler F, Lauer R, Tischlinger H, Mäuser M |title=The integument of pelagic crocodylomorphs (Thalattosuchia: Metriorhynchidae) |year=2021 |journal=Palaeontologia Electronica |volume=24 |issue=2 |pages=Article number 24.2.a25 |doi=10.26879/1099 |doi-access=free }}
• A study on the nasal and paranasal anatomy of thalattosuchians, and on its implications for the knowledge of the evolution of the paranasal sinus system and nasopharyngeal ducts in Thalattosuchia, is published by Cowgill et al. (2021).{{cite journal | vauthors = Cowgill T, Young MT, Schwab JA, Walsh S, Witmer LM, Herrera Y, Dollman KN, Choiniere JN, Brusatte SL | title = Paranasal sinus system and upper respiratory tract evolution in Mesozoic pelagic crocodylomorphs | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2583–2603 | doi = 10.1002/ar.24727 | pmid = 34398508 | s2cid = 237093183 }}
• Description of the cranial and endocranial anatomy of Macrospondylus bollensis is published by Wilberg et al. (2021).{{cite journal | vauthors = Wilberg EW, Beyl AR, Pierce SE, Turner AH | title = Cranial and endocranial anatomy of a three-dimensionally preserved teleosauroid thalattosuchian skull | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2620–2653 | doi = 10.1002/ar.24704 | pmid = 34259385 | s2cid = 235823836 }}
• A study on the innervation of the rostrum of metriorhynchoid thalattosuchians, and on its implications for the knowledge of the somatosensory abilities of these crocodylomorphs, is published by Bowman et al. (2021).{{cite journal | vauthors = Bowman CI, Young MT, Schwab JA, Walsh S, Witmer LM, Herrera Y, Choiniere J, Dollman KN, Brusatte SL | title = Rostral neurovasculature indicates sensory trade-offs in Mesozoic pelagic crocodylomorphs | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2654–2669 | doi = 10.1002/ar.24733 | pmid = 34428341 | s2cid = 237292970 }}
• Isolated metriorhynchid tooth crowns, representing some of the most recent known occurrences of Metriorhynchidae worldwide, are described from the Valanginian Kopřivnice Formation (Czech Republic) by Madzia et al. (2021), who interpret these specimens as evidence of the presence of two distinct lineages of geosaurin metriorhynchids in the area of Czech Republic during the Early Cretaceous.{{cite journal | vauthors = Madzia D, Sachs S, Young MT, Lukeneder A, Skupien P | title = Evidence of two lineages of metriorhynchid crocodylomorphs in the Lower Cretaceous of the Czech Republic | journal = Acta Palaeontologica Polonica | volume = 66 | issue = 2 | pages = 357–367 | year = 2021 | doi = 10.4202/app.00801.2020 | s2cid = 235247523 | doi-access = free | hdl = 10084/145230 | hdl-access = free }}
• A study on the anatomy of the braincase of a metriorhynchid specimen belonging or related to the species "Metriorhynchus" brachyrhynchus, and on the evolution of neurosensory and endocranial systems of metriorhynchids, is published by Schwab et al. (2021).{{cite journal| vauthors = Schwab JA, Young MT, Herrera Y, Witmer LM, Walsh SA, Katsamenis OL, Brusatte SL |title=The braincase and inner ear of 'Metriorhynchus' cf. 'M.' brachyrhynchus – implications for aquatic sensory adaptations in crocodylomorphs |year=2021 |journal=Journal of Vertebrate Paleontology |volume=41 |issue=1 |pages=e1912062 |doi=10.1080/02724634.2021.1912062 |bibcode=2021JVPal..41E2062S |s2cid=236276110|url=https://www.pure.ed.ac.uk/ws/files/192287775/56._Schwab.pdf }}
• A study on the anatomy of the snout of Dakosaurus andiniensis, and on the evolution of the facial anatomy of thalattosuchians, is published by Fernández & Herrera (2021), who interpret their findings as indicative of presence of anatomical adaptations likely helping drainage of nasal glands (probably excreting salt).{{cite journal | vauthors = Fernández MS, Herrera Y | title = Active airflow of the paranasal sinuses in extinct crocodyliforms: Evidence from a natural cast of the thalattosuchian Dakosaurus andiniensis | journal = The Anatomical Record | year = 2022 | volume = 305 | issue = 10 | pages = 2604–2619 | doi = 10.1002/ar.24678 | pmid = 34125496 | hdl = 11336/136755 | s2cid = 235425386 | hdl-access = free }}
• A study on histology and stable isotope geochemistry of the fossil material of Goniopholis and Dyrosaurus, and on their implications for the knowledge whether these crocodylomorphs were ectotherms or endotherms, is published by Faure-Brac et al. (2021).{{cite journal| vauthors = Faure-Brac MG, Amiot R, de Muizon C, Cubo J, Lécuyer C |title=Combined paleohistological and isotopic inferences of thermometabolism in extinct Neosuchia, using Goniopholis and Dyrosaurus (Pseudosuchia: Crocodylomorpha) as case studies |journal=Paleobiology |year=2022 |volume=48 |issue=2 |pages=302–323 |doi=10.1017/pab.2021.34 |bibcode=2022Pbio...48..302F |doi-access=free }}
• A study on the evolution of tethysuchian and gavialoid crocodylomorphs from the Campanian to the Thanetian is published by Jouve (2021).{{cite journal | vauthors = Jouve S | title = Differential diversification through the K-Pg boundary, and post-crisis opportunism in longirostrine crocodyliforms | journal = Gondwana Research | volume = 99 | pages = 110–130 | year = 2021 | doi = 10.1016/j.gr.2021.06.020 | bibcode = 2021GondR..99..110J | doi-access = free }}
• A study on the histology of the humeri and femora of Hyposaurus rogersii is published by Pellegrini et al. (2021).{{cite journal| vauthors = Pellegrini RA, Callahan WR, Hastings AK, Parris DC, McCauley JD |year=2021 |title= Skeletochronology and Paleohistology of Hyposaurus rogersii (Crocodyliformes, Dyrosauridae) from the Early Paleogene of New Jersey, USA |journal=Animals |volume=11 |issue=11 |pages=Article 3067 |doi=10.3390/ani11113067 |pmid=34827799 |pmc=8614569 |doi-access=free }}
• A study on the anatomy of the braincase and inner ear of Rhabdognathus aslerensis is published by Erb & Turner (2021).{{cite journal | vauthors = Erb A, Turner AH | title = Braincase anatomy of the Paleocene crocodyliform Rhabdognathus revealed through high resolution computed tomography | journal = PeerJ | volume = 9 | pages = e11253 | year = 2021 | doi = 10.7717/peerj.11253 |pmid=33986990 |pmc=8103917 | doi-access = free }}
• A study on the anatomy of the postcranial skeleton of Cerrejonisuchus improcerus is published by Scavezzoni & Fischer (2021), who also provide new information on the anatomy of the postcranial skeletons of Congosaurus bequaerti and Hyposaurus rogersii, and provide evidence of a distinctive postcranial anatomy of dyrosaurids among crocodyliforms.{{cite journal | vauthors = Scavezzoni I, Fischer V | title = The postcranial skeleton of Cerrejonisuchus improcerus (Crocodyliformes: Dyrosauridae) and the unusual anatomy of dyrosaurids | journal = PeerJ | volume = 9 | pages = e11222 | year = 2021 | doi = 10.7717/peerj.11222 | pmid = 34026348 | pmc = 8117932 | doi-access = free }}
• New fossil material of Deltasuchus motherali, providing new information on changes in the skeleton of this crocodyliform during the ontogeny, and indicative of dietary shifts from juvenile to adult, is described from the Cenomanian Woodbine Formation (Texas, United States) by Drumheller et al. (2021), who also study the phylogenetic relationships of D. motherali, and identify an endemic clade of Appalachian crocodyliforms, which they name Paluxysuchidae.{{Cite book|last1=Drumheller |first1=S. K. |last2=Adams |first2=T. L. |last3=Maddox |first3=H. |last4=Noto |first4=C. R. |year=2021 |title=Expanded Sampling Across Ontogeny in Deltasuchus motherali (Neosuchia, Crocodyliformes). Revealing Ecomorphological Niche Partitioning and Appalachian Endemism in Cenomanian Crocodyliforms |series=Elements of Paleontology |pages=1–67 |isbn=9781009042024 |doi=10.1017/9781009042024 |bibcode=2021esao.book.....D |s2cid=235524076 }}
• Redescription and a study on the phylogenetic relationships of Duerosuchus piscator is published by Narváez et al. (2021).{{cite journal| vauthors = Narváez I, de Celis A, Escaso F, De Jesús SM, Pérez-García A, Rodríguez A, Ortega F |title=Redescription and phylogenetic placement of the Spanish middle Eocene eusuchian Duerosuchus piscator (Crocodylia, Planocraniidae) |year=2021 |journal=Journal of Vertebrate Paleontology |volume=41 |issue=3 |pages=e1974868 |doi=10.1080/02724634.2021.1974868 |bibcode=2021JVPal..41E4868N |s2cid=242094589 |url=https://figshare.com/articles/dataset/Redescription_and_phylogenetic_placement_of_the_Spanish_middle_Eocene_eusuchian_i_Duerosuchus_piscator_i_Crocodylia_Planocraniidae_/16917659 |url-access=subscription }}
• A study on the phylogenetic relationships and the evolutionary history of crocodilians is published by Rio & Mannion (2021).{{cite journal| vauthors = Rio JP, Mannion PD |title=Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem |year=2021 |journal=PeerJ |volume=9 |pages=e12094 |doi=10.7717/peerj.12094 |pmid=34567843 |pmc=8428266 |doi-access=free }}
• New fossil material of Deinosuchus, representing one of the earliest records of this genus in North American reported to date, is described from the Campanian Menefee Formation (New Mexico, United States) by Mohler, McDonald & Wolfe (2021).{{cite journal| vauthors = Mohler BF, McDonald AT, Wolfe DG |year=2021 |title=First remains of the enormous alligatoroid Deinosuchus from the Upper Cretaceous Menefee Formation, New Mexico |journal=PeerJ |volume=9 |pages=e11302 |doi=10.7717/peerj.11302 |pmid=33981505 |pmc=8080887 |doi-access=free }}
• Description of the crocodyliform fossil material from the Eocene (Lutetian) Ikovo locality (Ukraine), including the easternmost record of diplocynodontines in Europe reported to date, is published by Kuzmin & Zvonok (2021), who also review the fossil record and biogeography of crocodyliforms from the Paleocene and Eocene of Europe.{{cite journal | vauthors = Kuzmin IT, Zvonok EA |year=2021 |title=Crocodylian assemblage from the middle Eocene Ikovo locality (Lugansk Province, Ukraine), with a discussion of the fossil record and geographic origins of crocodyliform fauna in the Paleogene of Europe |journal=Geobios |volume=65 |pages=7–27 |doi=10.1016/j.geobios.2021.02.002 |bibcode=2021Geobi..65....7K |s2cid=233596947 }}
• Description of additional fossil material of Tsoabichi greenriverensis from the Eocene Green River Formation, providing further evidence for its caimanine affinities, and a study on the evolutionary history of caimanines is published by Walter et al. (2021).{{cite journal| vauthors = Walter J, Darlim G, Massonne T, Aase A, Frey E, Rabi M |year=2021 |title=On the origin of Caimaninae: insights from new fossils of Tsoabichi greenriverensis and a review of the evidence |journal=Historical Biology |volume=34 |issue=4 |pages=580–595 |doi=10.1080/08912963.2021.1938563 |s2cid=238723638 }}
• Cidade & Rincón (2021) report the first occurrence of Acresuchus pachytemporalis from the Miocene Urumaco Formation (Venezuela), expanding known geographic distribution of this species.{{cite journal| vauthors = Cidade GM, Rincón AD |year=2021 |title=The first occurrence of Acresuchus (Alligatoroidea, Caimaninae) from the Urumaco Formation of Venezuela and the late Miocene crocodylian fauna of northern South America |journal=Journal of South American Earth Sciences |volume=110 |pages=Article 103344 |doi=10.1016/j.jsames.2021.103344 |bibcode=2021JSAES.11003344C }}
• Description and a study on the taxonomic status of the crocodylians from the Neogene Irrawaddy Formation (Myanmar), including one of the oldest records of the genus Gavialis reported to date, is published by Iijima et al. (2021).{{cite journal| vauthors = Iijima M, Takai M, Nishioka Y, Thaung-Htike, Zin-Maung-Maung-Thein, Egi N, Kusuhashi N, Tsubamoto T, Kono RT, Hirayama R | display-authors = 6 |year=2021 |title=Taxonomic overview of Neogene crocodylians in Myanmar |journal=Journal of Vertebrate Paleontology |volume=40 |issue=6 |pages=e1879100 |doi=10.1080/02724634.2021.1879100 | s2cid = 233619370 }}
• Revision of the taxonomy and a study on the phylogenetic relationships of the Miocene tomistomines from Italy and Malta is published by Nicholl et al. (2021).{{cite journal | vauthors = Nicholl CS, Rio JP, Mannion PD, Delfino M |year=2021 |title=A re-examination of the anatomy and systematics of the tomistomine crocodylians from the Miocene of Italy and Malta |journal=Journal of Systematic Palaeontology |volume=18 |issue=22 |pages=1853–1889 |doi=10.1080/14772019.2020.1855603 |s2cid=231636898 |url=https://discovery.ucl.ac.uk/id/eprint/10115334/ }}
• A study on the phylogenetic relationships of Voay robustus, based on mitochondrial genomic data, is published by Hekkala et al. (2021).{{cite journal| vauthors = Hekkala E, Gatesy J, Narechania A, Meredith R, Russello M, Aardema ML, Jensen E, Montanari S, Brochu C, Norell M, Amato G | display-authors = 6 |title=Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus |year=2021 |journal=Communications Biology |volume=4 | issue = 1 |pages=Article number 505 |doi=10.1038/s42003-021-02017-0 |doi-access=free |pmid=33907305 |pmc=8079395 }}
• Description of a new skull of Crocodylus anthropophagus from the DK site at Olduvai (Tanzania), representing the oldest fossil of a member of this species reported to date, and a study on the phylogenetic relationships of this species is published by Azzarà et al. (2021){{cite journal| vauthors = Azzarà B, Boschian G, Brochu CA, Delfino M, Dawid A, Iurino DA, Kimambo JS, Manzi G, Masao FT, Menconero S, Njau JK, Cherin M |title=A new cranium of Crocodylus anthropophagus from olduvai Gorge, northern Tanzania |year=2021 |journal=Rivista Italiana di Paleontologia e Stratigrafia |volume=127 | issue = 2 |pages=275–295 |doi=10.13130/2039-4942/15771 |s2cid=237962496 }}

• A study on the impact of the disparity between neonates and adults on the structure and diversity of dinosaur communities is published by Schroeder, Lyons & Smith (2021), who claim that communities with giant theropods lacked carnivores weighing 100 to 1000 kg, and argue that juveniles of giant theropod species likely filled the mesocarnivore niche, resulting in reduced overall taxonomic diversity;{{cite journal | vauthors = Schroeder K, Lyons SK, Smith FA | title = The influence of juvenile dinosaurs on community structure and diversity | journal = Science | volume = 371 | issue = 6532 | pages = 941–944 | date = February 2021 | pmid = 33632845 | doi = 10.1126/science.abd9220 | bibcode = 2021Sci...371..941S | s2cid = 232050541 | url = https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1860&context=bioscifacpub | url-access = subscription }} their conclusions are subsequently contested by Benson et al. (2022).{{cite journal | vauthors = Benson RB, Brown CM, Campione NE, Cullen TM, Evans DC, Zanno LE | title = Comment on "The influence of juvenile dinosaurs on community structure and diversity" | journal = Science | volume = 375 | issue = 6578 | pages = eabj5976 | year = 2022 | doi = 10.1126/science.abj5976 | pmid = 35050649 | s2cid = 246100083 | url = https://ora.ox.ac.uk/objects/uuid:458a4d23-21f9-4166-ab41-1338f2d409fa | doi-access = free }}{{cite journal | vauthors = Schroeder KM, Lyons SK, Smith FA | title = Response to Comment on "The influence of juvenile dinosaurs on community structure and diversity" | journal = Science | volume = 375 | issue = 6578 | pages = eabj7383 | year = 2022 | doi = 10.1126/science.abj7383 | pmid = 35050650 | s2cid = 246078669 }}
• Evidence of cessation of longitudinal skeletal growth in non-avian dinosaurs, inferred from a study of the articular surfaces of long bones, is presented by Rothschild & Witzmann (2021).{{cite journal | vauthors = Rothschild BM, Witzmann F | title = Identification of growth cessation in dinosaurs based on microscopy of long bone articular surfaces: preliminary results | journal = Alcheringa: An Australasian Journal of Palaeontology | volume = 45 | year = 2021 | issue = 2 | pages = 260–273 | doi = 10.1080/03115518.2021.1921273 | bibcode = 2021Alch...45..260R | s2cid = 236222208 }}
• A study aiming to determine the survivorship curves of Albertosaurus sarcophagus, Gorgosaurus libratus, Daspletosaurus torosus, Tyrannosaurus rex, Maiasaura peeblesorum and Psittacosaurus lujiatuensis in populations with an age distribution which was stable in shape over time is published by Griebeler (2021).{{cite journal | author = Griebeler EM | title = Dinosaurian survivorship schedules revisited: new insights from an age-structured population model | journal = Palaeontology | volume = 64 | issue = 6 | pages = 839–854 | year = 2021 | doi = 10.1111/pala.12576 |doi-access=free | bibcode = 2021Palgy..64..839G }}
• A study aiming to determine whether the presence of keratan sulfate is exclusive evidence for the presence of medullary bone in dinosaur fossils (and therefore whether it can be used to identify dinosaur specimens as gravid females) is published by Canoville et al. (2021).{{cite journal | vauthors = Canoville A, Zanno LE, Zheng W, Schweitzer MH | title = Keratan sulfate as a marker for medullary bone in fossil vertebrates | journal = Journal of Anatomy | volume = 238 | date = January 2021 | issue = 6 | pages = 1296–1311 | pmid = 33398875 | doi = 10.1111/joa.13388 | pmc = 8128763 }}
• A study on the variation in tail anatomy and length across the Dinosauria is published by Hone, Persons & Le Comber (2021).{{cite journal | vauthors = Hone DW, Persons WS, Le Comber SC | title = New data on tail lengths and variation along the caudal series in the non-avialan dinosaurs | journal = PeerJ | volume = 9 | pages = e10721 | year = 2021 | pmid = 33628634 | pmc = 7891087 | doi = 10.7717/peerj.10721 | doi-access = free }}
• A study on the possibilities of determination of the presence of sexual dimorphism in dinosaurs, evaluating whether the previous method used for dinosaurs correctly recognizes living animals as dimorphic, is published by Motani (2021).{{cite journal| vauthors = Motani R |title=Sex estimation from morphology in living animals and dinosaurs |year=2021 |journal=Zoological Journal of the Linnean Society |volume=192 |issue=4 |pages=1029–1044 |doi=10.1093/zoolinnean/zlaa181 |issn=0024-4082 |doi-access=free }}
• A study on the role of climate in shaping the geographic distribution of Mesozoic dinosaurs is published by Chiarenza et al. (2021).{{cite journal| vauthors = Chiarenza AA, Mannion PD, Farnsworth A, Carrano MT, Varela S |title=Climatic constraints on the biogeographic history of Mesozoic dinosaurs |year=2021 |journal=Current Biology |volume=32 |issue=3 |pages=570–585.e3 |doi=10.1016/j.cub.2021.11.061 |pmid=34921764 |s2cid=245273901 |url=https://discovery.ucl.ac.uk/id/eprint/10139144/ |doi-access=free |hdl=11093/5013 |hdl-access=free }}
• Review of the fossil record of Carnian dinosaurs from South America is published by Novas et al. (2021), who also interpret Chindesaurus, Daemonosaurus and Tawa as likely late-surviving members of Herrerasauria.{{cite journal| vauthors = Novas FE, Agnolin FL, Ezcurra MD, Müller RT, Martinelli A, Langer M |title=Review of the fossil record of early dinosaurs from South America, and its phylogenetic implications |year=2021 |journal=Journal of South American Earth Sciences |volume=110 |pages=Article 103341 |doi=10.1016/j.jsames.2021.103341 |bibcode=2021JSAES.11003341N }}
• A study on dinosaur trackways that show changes in direction from Jurassic and Cretaceous sites in North and South America, Europe and Asia is published by Lockley et al. (2021).{{cite journal| vauthors = Lockley MG, Xing L, Kim KS, Meyer CA |year=2021 |title=Tortuous trackways: evidence and implications of deviations, turns and changes in direction by dinosaurian trackmakers |journal=Historical Biology |volume=33 |issue=12 |pages=3326–3339 |doi=10.1080/08912963.2020.1865945 |bibcode=2021HBio...33.3326L |s2cid=234128960 }}
• Fossil trackways made by theropods, ornithopods and possibly ankylosaurs, are reported from the Folkestone Formation of the Lower Greensand Group by Hadland et al (2021), representing the youngest known footprints of non-avian dinosaurs known from the United Kingdom.{{Cite journal |author=Philip T. Hadland |author2=Steve Friedrich |author3=Abdelouahe Lagnaoui |author4=David M. Martill |date=2021|title=The youngest dinosaur footprints from England and their palaeoenvironmental implications|url=https://www.sciencedirect.com/science/article/abs/pii/S0016787821000419|journal=Proceedings of the Geologists' Association|volume=132|issue=4|pages=479–490|doi=10.1016/j.pgeola.2021.04.005|bibcode=2021PrGA..132..479H |s2cid=237785764|url-access=subscription}}
• A new dinosaur trackway is reported from the Early Cretaceous Eumeralla Formation (Wattle Hill, Australia), by Romilio and Godfrey (2021), who report the presence of ornithopod and bird-like tracks, as well as a large theropod footprint possibly belonging to the ichnogenus Megalosauropus.{{cite journal |last1=Romilio |first1=A |last2=Godfrey |first2=T |date=2021-12-09 |title=A new dinosaur tracksite from the Lower Cretaceous (Aptian–Albian) Eumeralla Formation of Wattle Hill, Victoria, Australia: a preliminary investigation |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2021.2014481?src=recsys |journal=Historical Biology |volume=34 |issue=12 |pages=2315–2323 | doi=10.1080/08912963.2021.2014481 |s2cid=253500472 |url-access=subscription }}
• A study on the climate of the Lufeng area (China) during the Early Jurassic, and on the relations between the global distribution of dinosaur fossils and climate during the Jurassic, is published by Shen et al. (2021).{{Cite journal|last1=Shen |first1=H. |last2=Zhang |first2=L. |last3=Wang |first3=C. |last4=Amiot |first4=R. |last5=Wang |first5=X. |last6=Cui |first6=L. |last7=Song |first7=P. |year=2021 |title=Early Jurassic palaeoclimate in Southwest China and its implications for dinosaur fossil distribution |journal=Geological Journal |volume=56 |issue=12 |pages=6245–6258 |doi=10.1002/gj.4168 |bibcode=2021GeolJ..56.6245S |s2cid=236354974 |url=https://hal.archives-ouvertes.fr/hal-03374063/file/GJ-20-0472_Proof_hi.pdf }}
• A study on the relationships between diet, tooth complexity and tooth replacement rates in Late Jurassic dinosaurs is published by Melstrom, Chiappe & Smith (2021).{{cite journal| vauthors = Melstrom KM, Chiappe LM, Smith ND |year=2021 |title=Exceptionally simple, rapidly replaced teeth in sauropod dinosaurs demonstrate a novel evolutionary strategy for herbivory in Late Jurassic ecosystems |journal=BMC Ecology and Evolution |volume=21 |issue=1 |pages=Article number 202 |doi=10.1186/s12862-021-01932-4 |pmid=34742237 |pmc=8571970 |doi-access=free }}
• Description of the fossil material of a tyrannosauroid theropod and an early member of the family Hadrosauridae from the Upper Cretaceous Merchantville Formation (Delaware and New Jersey, United States), possibly representing new taxa, and a study on the phylogenetic affinities of these dinosaurs is published by Brownstein (2021).{{cite journal | author = Brownstein CD |year=2021 |title=Dinosaurs from the Santonian–Campanian Atlantic coastline substantiate phylogenetic signatures of vicariance in Cretaceous North America |journal=Royal Society Open Science |volume=8 |issue=8 |pages=Article ID 210127 |doi=10.1098/rsos.210127 |pmid=34457333 |pmc=8385347 |bibcode=2021RSOS....810127D |doi-access=free }}
• Druckenmiller et al. (2021) report the discovery of a diverse assemblage of herbivorous and carnivorous non-avian dinosaurs, including perinatal and very young specimens, from the Upper Cretaceous Prince Creek Formation (Alaska, United States), and interpret this finding as indicating that most, if not all, dinosaurs from this assemblage were nonmigratory year-round Arctic residents.{{cite journal | vauthors = Druckenmiller PS, Erickson GM, Brinkman D, Brown CM, Eberle JJ | title = Nesting at extreme polar latitudes by non-avian dinosaurs | journal = Current Biology | volume = 31 | issue = 16 | pages = 3469–3478.e5 | year = 2021 | doi = 10.1016/j.cub.2021.05.041 | pmid = 34171301 | s2cid = 235631483 | doi-access = free | bibcode = 2021CBio...31E3469D }}
• A study on the distribution of dinosaurs across the latest Cretaceous of North America is published by García-Girón et al. (2021).{{cite journal| vauthors = García-Girón J, Heino J, Alahuhta J, Chiarenza AA, Brusatte SL |year=2021 |title=Palaeontology meets metacommunity ecology: the Maastrichtian dinosaur fossil record of North America as a case study |journal=Palaeontology |volume=64 |issue=3 |pages=335–357 |doi=10.1111/pala.12526|bibcode=2021Palgy..64..335G |hdl=20.500.11820/92a3b0bb-83d5-4c09-9afb-8ee386bdaf92 |issn=0031-0239 |s2cid=233819979 |url=https://www.research.ed.ac.uk/en/publications/92a3b0bb-83d5-4c09-9afb-8ee386bdaf92 |hdl-access=free }}
• A study aiming to determine whether plant-eating dinosaurs could have moved seeds long distances is published by Perry (2021).{{cite journal | vauthors = Perry GL | title = How far might plant-eating dinosaurs have moved seeds? | journal = Biology Letters | volume = 17 | issue = 1 | pages = 20200689 | date = January 2021 | pmid = 33401998 | pmc = 7876603 | doi = 10.1098/rsbl.2020.0689 | doi-access = free }}
• Dinosaur tracks with elongated metatarsal marks and superficially human-like appearance are interpreted by Lallensack, Farlow & Falkingham (2021) as more likely to be caused by deep penetrations of the foot in soft sediment than by a plantigrade mode of locomotion.{{cite journal| vauthors = Lallensack JN, Farlow JO, Falkingham PL |title=A new solution to an old riddle: elongate dinosaur tracks explained as deep penetration of the foot, not plantigrade locomotion |year=2021 |journal=Palaeontology |volume=65 |doi=10.1111/pala.12584 |s2cid=245017775 |url=https://researchonline.ljmu.ac.uk/id/eprint/15899/1/Lallensack%20Farlow%20Falkingham%202021%20Palaeontology%20elongate%20tracks.pdf }}
• A study on changes of diversity of dinosaurs belonging to the families Ankylosauridae, Ceratopsidae, Hadrosauridae, Dromaeosauridae, Troodontidae and Tyrannosauridae during the Late Cretaceous is published by Condamine et al. (2021), who interpret their findings as indicative of a decline of non-avian dinosaur diversity during the last 10 million years of the Cretaceous period, and attempt to determine possible causes of this decline.{{cite journal | vauthors = Condamine FL, Guinot G, Benton MJ, Currie PJ | title = Dinosaur biodiversity declined well before the asteroid impact, influenced by ecological and environmental pressures | journal = Nature Communications | volume = 12 | pages = Article number 3833 | year = 2021 | issue = 1 | doi = 10.1038/s41467-021-23754-0 | pmid = 34188028 | pmc = 8242047 | bibcode = 2021NatCo..12.3833C }}
• The study published by Bonsor et al. (2020), aiming to determine whether non-avian dinosaurs were in long-term decline prior to the Cretaceous–Paleogene extinction event,{{cite journal | vauthors = Bonsor JA, Barrett PM, Raven TJ, Cooper N |year=2020 |title=Dinosaur diversification rates were not in decline prior to the K-Pg boundary |journal=Royal Society Open Science |volume=7 |issue=11 |pages=Article ID 201195 |doi=10.1098/rsos.201195 |doi-access=free |pmc=7735361 |pmid=33391800 |bibcode=2020RSOS....701195B |s2cid=226981705 }} is criticized by Sakamoto, Benton & Venditti (2021).{{cite journal | vauthors = Sakamoto M, Benton MJ, Venditti C |year=2021 |title=Strong support for a heterogeneous speciation decline model in Dinosauria: a response to claims made by Bonsor et al. (2020) |journal=Royal Society Open Science |volume=8 |issue=8 |pages=Article ID 202143 |doi=10.1098/rsos.202143 |pmid=34457325 |pmc=8385376 |bibcode=2021RSOS....802143S |doi-access=free }}
• A study on a dinosaur nesting site preserved in the Upper Cretaceous Wido Volcanics (Wi Island, South Korea) is published by Kim et al. (2021; final version published in 2022), providing new information on how these dinosaurs chose their nesting sites.{{cite journal|vauthors=Kim S, Hwang IG, Ghim YS, Kim N, Lee Y|title=Upper Cretaceous (Coniacian-Santonian) dinosaur nesting colony preserved in abandoned crevasse splay deposits, Wi Island, South Korea|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume= 585|year=2022|pages=110728|issn=0031-0182|doi=10.1016/j.palaeo.2021.110728|bibcode=2022PPP...58510728K|s2cid=239975835|doi-access=free}}

• New fossil material of theropod and sauropod dinosaurs, including a caudal vertebra with pneumatic internal structures rarely observed outside Late Cretaceous South American saltasaurines, is described from the Campanian Quseir Formation (Egypt) by Salem et al. (2021).{{cite journal| vauthors = Salem BS, O'Connor PM, Gorscak E, El-Sayed S, Sertich JJ, Seiffert E, Sallam HM |title=Dinosaur remains from the Upper Cretaceous (Campanian) of the Western Desert, Egypt |journal=Cretaceous Research |year=2021 |volume=123 |pages=Article 104783 |doi=10.1016/j.cretres.2021.104783 |bibcode=2021CrRes.12304783S |s2cid=233900405 |doi-access=free }}
• Evidence indicating that some mid-sized dendroolithid eggs were laid by a therizinosauroid theropod is presented by Kundrát & Cruickshank (2021), who also report the discovery of putative embryonic remains (possibly of a titanosaur sauropod) in a faveoloolithid egg.{{cite journal| vauthors = Kundrát M, Cruickshank AR |year=2021 |title=New information on multispherulitic dinosaur eggs: Faveoloolithidae and Dendroolithidae |journal=Historical Biology |volume=34 |issue=6 |pages=1072–1084 |doi=10.1080/08912963.2021.1961764 |s2cid=238687752 }}
• Putative large-sized sauropodomorph specimen from the Carnian strata at the 'Cerro da Alemoa' locality (southern Brazil) is reinterpreted as a herrerasaurid specimen (the largest dinosaur reported from the Candelária Sequence to date) by Garcia et al. (2021).{{cite journal| vauthors = Garcia MS, Müller RT, Pretto FA, Da-Rosa ÁA, Dias-Da-Silva S |year=2021 |title=Taxonomic and phylogenetic reassessment of a large-bodied dinosaur from the earliest dinosaur-bearing beds (Carnian, Upper Triassic) from southern Brazil |journal=Journal of Systematic Palaeontology |volume=19 |issue=1 |pages=1–37 |doi=10.1080/14772019.2021.1873433 |bibcode=2021JSPal..19....1G |s2cid=232313141 }}
• Putative tracks of a large-bodied predatory dinosaur from the Upper Triassic Blackstone Formation (Australia) are reinterpreted by Romilio et al. (2021) as sharing characteristics with the sauropodomorph ichnogenus Evazoum, and possibly representing the first evidence of basal sauropodomorph dinosaurs from Australia.{{cite journal| vauthors = Romilio A, Klein H, Jannel A, Salisbury SW |year=2021 |title=Saurischian dinosaur tracks from the Upper Triassic of southern Queensland: possible evidence for Australia's earliest sauropodomorph trackmaker |journal=Historical Biology |volume=34 |issue=9 |pages=1834–1843 |doi=10.1080/08912963.2021.1984447 |s2cid=239170287 |url=https://www.tandfonline.com/doi/abs/10.1080/08912963.2021.1984447 |url-access=subscription }}

• A study aiming to determine whether the knowledge of patterns of species abundance and clade diversity in theropod dinosaurs is significantly impacted by the diagnosability of their fossils is published by Cashmore, Butler & Maidment (2021).{{cite journal| vauthors = Cashmore DD, Butler RJ, Maidment SC |year=2021 |title=Taxonomic identification bias does not drive patterns of abundance and diversity in theropod dinosaurs |journal=Biology Letters |volume=17 |issue=7 |pages=Articles ID 20210168 |doi=10.1098/rsbl.2021.0168 |pmid=34256583 |pmc=8278044 }}
• A study on the evolution of vision and hearing modalities in theropod dinosaurs is published by Choiniere et al. (2021), who interpret their findings as indicative of early evolution of nocturnal predation in alvarezsauroid theropods.{{cite journal| vauthors = Choiniere JN, Neenan JM, Schmitz L, Ford DP, Chapelle KE, Balanoff AM, Sipla JS, Georgi JA, Walsh SA, Norell MA, Xu X, Clark JM, Benson RB |title=Evolution of vision and hearing modalities in theropod dinosaurs |year=2021 |journal=Science |volume=372 |issue=6542 |pages=610–613 |doi=10.1126/science.abe7941 |pmid=33958472 |bibcode=2021Sci...372..610C |s2cid=233872840 |url=https://ora.ox.ac.uk/objects/uuid:c9faa76c-de6a-470f-bfc4-0aaf82bda030 }}
• A study on changes of feeding mechanics of theropods throughout their evolutionary history is published by Ma et al. (2021).{{cite journal| vauthors = Ma W, Pittman M, Butler RJ, Lautenschlager S |title=Macroevolutionary trends in theropod dinosaur feeding mechanics |year=2021 |journal=Current Biology |volume=32 |issue=3 |pages=677–686.e3 |doi=10.1016/j.cub.2021.11.060 |pmid=34919807 |s2cid=245257271 |doi-access=free }}
• Bishop et al. (2021) create three-dimensional simulations of gait in Coelophysis bauri, and interpret their findings as indicative of a crucial and dynamic role of the tail in the locomotion of this theropod.{{cite journal| vauthors = Bishop PJ, Falisse A, De Groote F, Hutchinson JR |year=2021 |title=Predictive simulations of running gait reveal a critical dynamic role for the tail in bipedal dinosaur locomotion |journal=Science Advances |volume=7 |issue=39 |pages=eabi7348 |doi=10.1126/sciadv.abi7348 |doi-access=free |pmid=34550734 |pmc=8457660 |bibcode=2021SciA....7.7348B }}
• A vertebra of a non-coelophysoid, non-averostran neotheropod which may be 15 million years older than Dilophosaurus wetherilli is described from the Lower Jurassic (Hettangian) Whitmore Point Member of the Moenave Formation (Utah, United States) by Marsh et al. (2021), who interpret this finding as indicating that not all contemporaneous theropod traces were made by coelophysoids.{{cite journal| vauthors = Marsh AD, Milner AR, Harris JD, De Blieux DD, Kirkland JI |year=2021 |title=A non-averostran neotheropod vertebra (Dinosauria: Theropoda) from the earliest Jurassic Whitmore Point Member (Moenave Formation) in southwestern Utah |journal=Journal of Vertebrate Paleontology |volume=41 |issue=1 |pages=e1897604 |doi=10.1080/02724634.2021.1897604 |bibcode=2021JVPal..41E7604M |s2cid=236290889 }}
• McMenamin (2021) describes a humerus of a neotheropod from the Portland Formation of the Early Jurassic (Massachucetts, USA) older and larger than Dilophosaurus, and interpret it as a large piscovorous creature based on the locale's ecology.McMenamin, M. (2021). [https://www.researchgate.net/publication/354890286_Large_neotheropod_from_the_Lower_Jurassic_of_Massachusetts Large neotheropod from the Lower Jurassic of Massachusetts]. AcademiaLetters, Article 3591. {{doi|10.20935/AL3591.1©2021}} by the author — Open Access — Distributed under CC BY 4.0
• An assemblage of over 100 theropod footprints of various size and morphology is described from the Lower Jurassic Fengjiahe Formation (China) by Li et al. (2021), representing the track site with the largest number of theropod footprints in Yunnan reported to date.{{cite journal| vauthors = Li H, Peyre de Fabrègues C, Bi S, Wang Y, Xu X |year=2021 |title=The largest theropod track site in Yunnan, China: a footprint assemblage from the Lower Jurassic Fengjiahe Formation |journal=PeerJ |volume=9 |pages=e11788 |doi=10.7717/peerj.11788 |pmid=34707920 |pmc=8500084 |doi-access=free }}
• New fossil material of ceratosaur theropods, probably representing one of the oldest known record of abelisaurids, is described from the Upper Jurassic Cañadón Calcáreo Formation (Argentina) by Rauhut & Pol (2021).{{cite journal| vauthors = Rauhut OW, Pol D |year=2021 |title=New theropod remains from the Late Jurassic Cañadón Calcáreo formation of Chubut, Argentina |journal=Journal of South American Earth Sciences |volume=111 |pages=Article 103434 |doi=10.1016/j.jsames.2021.103434 |bibcode=2021JSAES.11103434R }}
• A study on the skeletal anatomy and phylogenetic relationships of Xenotarsosaurus bonapartei is published by Ibiricu et al. (2021).{{cite journal| vauthors = Ibiricu LM, Baiano MA, Martínez RD, Alvarez BN, Lamanna MC, Casal GA |title=A detailed osteological description of Xenotarsosaurus bonapartei (Theropoda: Abelisauroidae): implications for abelisauroid phylogeny |journal=Cretaceous Research |year=2021 |volume=124 |pages=Article 104829 |doi=10.1016/j.cretres.2021.104829 |bibcode=2021CrRes.12404829I |s2cid=233653593 }}
• Two new furileusaurian abelisaurid specimens from the Santonian Bajo de la Carpa Formation (Argentina), providing new information on the abundance of abelisaurids in this area and on variety of abelisaurid morphotypes that coexisted in the north of Argentine Patagonia during the Late Cretaceous, are described by Méndez et al. (2021; final version published in 2022).{{cite journal| vauthors = Méndez AH, Gianechini FA, Paulina-Carabajal A, Filippi LS, Juárez-Valieri RD, Cerda IA, Garrido AC |title=New furileusaurian remains from La Invernada (northern Patagonia, Argentina): A site of unusual abelisaurids abundance |journal=Cretaceous Research |year=2021 |volume=129 |pages=Article 104989 |doi=10.1016/j.cretres.2021.104989 | issn=0195-6671 |s2cid=238646344 }}
• Description of the preserved integument of Carnotaurus sastrei is published by Hendrickx & Bell (2021).{{cite journal| vauthors = Hendrickx C, Bell PR |title=The scaly skin of the abelisaurid Carnotaurus sastrei (Theropoda: Ceratosauria) from the Upper Cretaceous of Patagonia |journal=Cretaceous Research |year=2021 |volume=128 |pages=Article 104994 |doi=10.1016/j.cretres.2021.104994 |bibcode=2021CrRes.12804994H }}
• Revision of the phylogenetic affinities and evolutionary significance of Saltriovenator zanellai and Scipionyx samniticus is published by Cau (2021), who interprets his findings as raising doubts on the systematic status of theropod specimens assigned to the family Compsognathidae, which might turn out to be immature individuals belonging to various lineages of large-bodied tetanurans, with the holotype specimen of S. samniticus possibly being an immature carcharodontosaurid.{{cite journal|last=Cau |first=A. |year=2021 |title=Comments on the Mesozoic theropod dinosaurs from Italy |journal=Atti della Società dei Naturalisti e dei Matematici di Modena |volume=152 |pages=81–95 |url=https://www.researchgate.net/publication/354418322 }}
• Two trackways belonging to fast-running theropods (probably basal tetanurans) are described from the Lower Cretaceous Enciso Group (Spain) by Navarro-Lorbés et al. (2021), who present the speeds of locomotion calculated for both trackways, which are among the top speeds ever calculated for non-avian theropod tracks, and interpret one of the trackways as produced by a dinosaur with the ability to make and control substantial speed changes while running.{{cite journal| vauthors = Navarro-Lorbés P, Ruiz J, Díaz-Martínez I, Isasmendi E, Sáez-Benito P, Viera L, Pereda-Suberbiola X, Torices A |title=Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 23095 |doi=10.1038/s41598-021-02557-9 |pmid=34887437 |pmc=8660891 |bibcode=2021NatSR..1123095N | doi-access = free }}
• Spinosaurid neck vertebrae distinct from known vertebrae of Spinosaurus aegyptiacus and exhibiting an unusual combination of positionally variable characters are described from the Kem Kem Group (Morocco) by McFeeters (2021), who interprets this finding as evidence of a greater degree of intraspecific variation in the vertebrae of S. aegyptiacus than previously recognized, or alternatively, evidence for the occurrence of two spinosaurid taxa in the Kem Kem Group.{{cite journal| vauthors = McFeeters B |year=2021 |title=New mid-cervical vertebral morphotype of Spinosauridae from the Kem Kem Group of Morocco |journal=Vertebrate Anatomy Morphology Palaeontology |volume=8 |pages=182–193 |doi=10.18435/vamp29370 |doi-access=free }}
• Spinosaurid caudal vertebrae are described from the Lower Cretaceous Sao Khua Formation (Thailand) by Samathi, Sander & Chanthasit (2021), who also reinterpret the putative ceratosaur Camarillasaurus cirugedae as a spinosaurid.{{cite journal| vauthors = Samathi A, Sander PM, Chanthasit P |year=2021 |title=A spinosaurid from Thailand (Sao Khua Formation, Early Cretaceous) and a reassessment of Camarillasaurus cirugedae from the Early Cretaceous of Spain |journal=Historical Biology |volume=33 |issue=12 |pages=3480–3494 |doi=10.1080/08912963.2021.1874372 |bibcode=2021HBio...33.3480S |s2cid=233884025 }}
• A study on the diversity of the premaxillae shape in spinosaurids, an on its implications for the knowledge of the phylogenetic relationships of the spinosaurids, is published by Lacerda, Grillo & Romano (2021).{{cite journal| vauthors = Lacerda MB, Grillo ON, Romano PS |title= Rostral morphology of Spinosauridae (Theropoda, Megalosauroidea): premaxilla shape variation and a new phylogenetic inference |journal=Historical Biology |year=2022 |volume=34 |issue=11 |pages=2089–2109 |doi=10.1080/08912963.2021.2000974 |bibcode= 2022HBio...34.2089L |s2cid=244418803 |url=https://figshare.com/articles/journal_contribution/17040228 }}
• Hone & Holtz (2021) evaluate the evidence for the competing interpretations of the ecology of Spinosaurus, and reject the interpretation of this theropod as a specialised aquatic pursuit predator.{{cite journal| vauthors = Hone DW, Holtz TR |title=Evaluating the ecology of Spinosaurus: Shoreline generalist or aquatic pursuit specialist? |year=2021 |journal=Palaeontologia Electronica |volume=24 |issue=1 |pages=Article number 24(1):a03 |doi=10.26879/1110 |doi-access=free |hdl=1903/28570 |hdl-access=free }}
• Pahl and Ruedas (2021) suggest that carnosaurs like Allosaurus were primarily scavengers that fed on sauropod carcasses, which they consider to be analogous to whale falls;{{Cite journal|last1=Pahl|first1=Cameron C.|last2=Ruedas|first2=Luis A.|year=2021|title=Carnosaurs as Apex Scavengers: Agent-based simulations reveal possible vulture analogues in late Jurassic Dinosaurs|journal=Ecological Modelling|volume=458|pages=109706|doi=10.1016/j.ecolmodel.2021.109706|bibcode=2021EcMod.45809706P | issn=0304-3800 }} however, their conclusions are criticized by Kane et al. (2023){{Cite journal |last1=Kane |first1=Adam |last2=Healy |first2=Kevin |last3=Ruxton |first3=Graeme D. |year=2023 |title=Was Allosaurus really predominantly a scavenger? |url=https://www.sciencedirect.com/science/article/pii/S0304380022003453 |journal=Ecological Modelling |volume=476 |pages=110247 |doi=10.1016/j.ecolmodel.2022.110247 |bibcode=2023EcMod.47610247K |s2cid=254712679 |issn=0304-3800|url-access=subscription }} but later defended by Pahl and Ruehdas (2023).{{Cite journal |last1=Pahl |first1=Cameron C. |last2=Ruedas |first2=Luis A. |date=2023-03-01 |title=Allosaurus was predominantly a scavenger |url=https://www.sciencedirect.com/science/article/pii/S0304380022003593 |journal=Ecological Modelling |language=en |volume=477 |pages=110261 |doi=10.1016/j.ecolmodel.2022.110261 |bibcode=2023EcMod.47710261P |s2cid=255661337 |issn=0304-3800|url-access=subscription }}
• A study on the histology and geochemistry of a tibia and a femur of a specimen or specimens of Allosaurus fragilis from the Cleveland-Lloyd Dinosaur Quarry (Utah, United States), and on its implications for the knowledge of the growth strategy of this species, is published by Ferrante et al. (2021).{{cite journal| vauthors = Ferrante C, Cavin L, Vennemann T, Martini R |year=2021 |title=Histology and Geochemistry of Allosaurus (Dinosauria: Theropoda) From the Cleveland-Lloyd Dinosaur Quarry (Late Jurassic, Utah): Paleobiological Implications |journal=Frontiers in Earth Science |volume=9 |pages=Article 641060 |doi=10.3389/feart.2021.641060 |bibcode=2021FrEaS...9..225F |s2cid=233131160 |doi-access=free }}
• Caudal vertebra of a theropod with affinities to Carcharodontosauria is described from the Upper Jurassic Sergi Formation by Bandeira et al. (2021), representing the first unambiguous record of a dinosaur from the Jurassic of Brazil reported to date.{{cite journal | vauthors = Bandeira KL, Brum AS, Pêgas RV, Souza LG, Pereira PV, Pinheiro AE | title = The first Jurassic theropod from the Sergi Formation, Jatobá Basin, Brazil | journal = Anais da Academia Brasileira de Ciências | volume = 93 | issue = suppl 2 | pages = e20201557 | year = 2021 | doi = 10.1590/0001-3765202120201557 | doi-broken-date = 11 January 2025 | pmid = 34378647 | url = https://www.scielo.br/j/aabc/a/7bvvDZNDTwCxTvZWcCjSLmF/?lang=en | url-access = subscription }}
• A study on the phylogenetic affinities of putative carcharodontosaurid teeth from the Upper Cretaceous strata in northern and central Patagonia, and on their implications for the knowledge of the timing of extinction of carcharodontosaurids in South America, is published by Meso et al. (2021).{{cite journal| vauthors = Meso JG, Juárez Valieri RD, Porfiri JD, Correa SA, Martinelli AG, Casal GA, Canudo JI, Poblete F, Dos Santos D |title=Testing the persistence of Carcharodontosauridae (Theropoda) in the Upper Cretaceous of Patagonia based on dental evidence |journal=Cretaceous Research |year=2021 |volume=125 |pages=Article 104875 |doi=10.1016/j.cretres.2021.104875|bibcode=2021CrRes.12504875M |hdl=11336/183886 |issn=0195-6671 |hdl-access=free }}
• Description of new fossil material of Phuwiangvenator yaemniyomi from the Lower Cretaceous Sao Khua Formation (Thailand), and a study on its implications for the knowledge of the early evolution of Megaraptora, is published by Samathi et al. (2021).{{cite journal| vauthors = Samathi A, Suteethorn S, Pradit N, Suteethorn V |title=New material of Phuwiangvenator yaemniyomi (Dinosauria: Theropoda) from the type locality: implications for the early evolution of Megaraptora |journal=Cretaceous Research |year=2021 |volume=131 |pages=Article 105093 |doi=10.1016/j.cretres.2021.105093 |s2cid=244363244 }}
• A study on the skeletal anatomy of Aerosteon riocoloradensis is published by Aranciaga Rolando et al. (2021).{{cite journal| vauthors = Aranciaga Rolando A, Méndez A, Canale J, Novas F |year=2021 |title=Osteology of Aerosteon riocoloradensis (Sereno et al. 2008) a large megaraptoran (Dinosauria: Theropoda) from the Upper Cretaceous of Argentina |journal=Historical Biology |volume=34 |issue=2 |pages=226–282 |doi=10.1080/08912963.2021.1910816 |s2cid=237682552 }}
• Fragmentary specimens of tyrannosaurid theropods from the Dinosaur Park Formation of the Alberta, Canada) in the collection of the San Diego Natural History Museum were described by Yun (2021).{{cite journal| vauthors = Yun CG |title=Tyrannosaurid theropod specimens in the San Diego Natural History Museum from the Dinosaur Park Formation (Campanian) of Alberta, Canada |year=2021 |journal=New Mexico Museum of Natural History and Science Bulletin |volume=82 |pages=569–578 |url=https://www.researchgate.net/publication/347993228 }}
• Bones of tyrannosaurid theropods with extensive tooth marks matching the teeth of tyrannosaurids are described from the Upper Cretaceous of the San Juan Basin (northwestern New Mexico, United States) by Dalman & Lucas (2021), who interpret this finding as evidence for cannibalistic behavior among tyrannosaurids.{{cite journal| vauthors = Dalman SG, Lucas SG |title=New evidence for cannibalism in tyrannosaurid dinosaurs from the Upper Cretaceous (Campanian/Maastrichtian) San Juan Basin of New Mexico |year=2021 |journal=New Mexico Museum of Natural History and Science Bulletin |volume=82 |pages=39–56 |url=https://www.researchgate.net/publication/348002335 }}
• Caneer, Moklestad & Lucas (2021) describe structures which are not readily assignable to any known ichnotaxon from the Upper Cretaceous of the Raton Basin (New Mexico), and interpret them as one footprint and two forearm/hand prints probably produced by a large tyrannosaurid theropod standing up from a prone position.{{cite journal| vauthors = Caneer T, Moklestad T, Lucas SG |title=Tracks in the Upper Cretaceous of the Raton Basin possibly show tyrannosaurid rising from a prone position |year=2021 |journal=New Mexico Museum of Natural History and Science Bulletin |volume=82 |pages=29–37 |url=https://www.researchgate.net/publication/348002331 }}
• Perinatal tyrannosaurid bones and teeth are described from the Upper Cretaceous Two Medicine Formation (Montana, United States) and Horseshoe Canyon Formation (Alberta, Canada) by Funston et al. (2021), who evaluate the implications of these findings for the knowledge of the minimum hatchling size of tyrannosaurids, their nesting habits and development of their teeth.{{cite journal| vauthors = Funston GF, Powers MJ, Whitebone SA, Brusatte SL, Scannella JB, Horner JR, Currie PJ |title=Baby tyrannosaurid bones and teeth from the Late Cretaceous of western North America |journal=Canadian Journal of Earth Sciences |year=2021 |volume=58 |issue=9 |pages=756–777 |doi=10.1139/cjes-2020-0169 |bibcode=2021CaJES..58..756F |hdl=20.500.11820/3a870ad5-7258-4fcb-a3b7-238e448c04b4 |s2cid=234053280 |url=https://www.pure.ed.ac.uk/ws/files/180195224/545._Greg.pdf }}
• A study on tyrannosaurid tracks from the Campanian Wapiti Formation (Alberta, Canada), evaluating the implications of these tracks for the knowledge of changes in pedal anatomy of tyrannosaurids during their ontogeny, is published by Enriquez et al. (2021).{{cite journal| vauthors = Enriquez NJ, Campione NE, Brougham T, Fanti F, White MA, Sissons RL, Sullivan C, Vavrek MJ, Bell PR | display-authors = 6|year=2021 |title=Exploring possible ontogenetic trajectories in tyrannosaurids using tracks from the Wapiti Formation (upper Campanian) of Alberta, Canada |journal=Journal of Vertebrate Paleontology |volume=40 |issue=6 |pages=e1878201 |doi=10.1080/02724634.2021.1878201 | s2cid = 234814620}}
• Tyrannosaurid fossil material is described from the Blagoveshchensk and Kundur fossil localities (Amur Region, Russia) by Bolotsky, Ermatsans & Bolotsky (2021).{{cite journal| vauthors = Bolotsky IY, Ermatsans IA, Bolotsky YL |title=Tyrannosaurid remains (Dinosauria: Tyrannosauridae) from localities in Blagoveshchensk and Kundur (Amur Region, Russia) |year=2021 |journal=Biota and Environment of Natural Areas |volume=2021 |issue=2 |pages=49–70 |doi=10.37102/2782-1978_2021_2_4 |s2cid=245529797 }}
• A study on possible causes of monopolization of large carnivore guilds in Asian and American dinosaur assemblages by tyrannosaurids in the latest Cretaceous is published by Holtz (2021).{{cite journal| vauthors = Holtz TR |title=Theropod guild structure and the tyrannosaurid niche assimilation hypothesis: implications for predatory dinosaur macroecology and ontogeny in later Late Cretaceous Asiamerica |journal=Canadian Journal of Earth Sciences |year=2021 |volume=58 |issue=9 |pages=778–795 |doi=10.1139/cjes-2020-0174 |hdl=1903/28566 |hdl-access=free }}
• A study on the morphology, frequency, and ontogeny of facial bite marks in tyrannosaurid specimens is published by Brown, Currie & Therrien (2021), who interpret the ontogenetic distribution of bite scars in the studied specimens as possible evidence of agonistic behaviour associated with the onset of sexual maturity.{{cite journal| vauthors = Brown CM, Currie PJ, Therrien F |title=Intraspecific facial bite marks in tyrannosaurids provide insight into sexual maturity and evolution of bird-like intersexual display |year=2021 |journal=Paleobiology |volume=48 |pages=12–43 |doi=10.1017/pab.2021.29 |s2cid=239632592 }}
• A study on changes of mandibular biomechanical properties and tooth morphology in Albertosaurus sarcophagus and Gorgosaurus libratus during their ontogeny is published by Therrien et al. (2021), who interpret their findings as indicating the occurrence of ontogenetic dietary shift in albertosaurine tyrannosaurids.{{cite journal| vauthors = Therrien F, Zelenitsky DK, Voris JT, Tanaka K |title=Mandibular force profiles and tooth morphology in growth series of Albertosaurus sarcophagus and Gorgosaurus libratus (Tyrannosauridae: Albertosaurinae) provide evidence for an ontogenetic dietary shift in tyrannosaurids |journal=Canadian Journal of Earth Sciences |year=2021 |volume=58 |issue=9 |pages=812–828 |doi=10.1139/cjes-2020-0177 |bibcode=2021CaJES..58..812T |s2cid=234026715 }}
• A study on the mechanical properties of the mandibles of tyrannosaurine tyrannosaurids representing different ontogenetic stages (including small juvenile) is published by Rowe & Snively (2021).{{cite journal | vauthors = Rowe AJ, Snively E | title = Biomechanics of juvenile tyrannosaurid mandibles and their implications for bite force: Evolutionary biology | journal = Anatomical Record | volume = 305 | issue = 2 | pages = 373–392 | date = February 2021 | pmid = 33586862 | doi = 10.1002/ar.24602 | s2cid = 231927717 | doi-access = free }}
• New bone bed containing at least four specimens of Teratophoneus curriei or a related tyrannosaurid is described from the Campanian Kaiparowits Formation (Utah, United States) by Titus et al. (2021), who study the taphonomy of this bone bed, and evaluate its implications for the knowledge whether known accumulations of tyrannosaurid specimens represent time-averaged or forced accumulations, or whether they are evidence of gregariousness of tyrannosaurids.{{cite journal| vauthors = Titus AL, Knoll K, Sertich JJ, Yamamura D, Suarez CA, Glasspool IJ, Ginouves JE, Lukacic AK, Roberts EM | display-authors = 6 |year=2021 |title=Geology and taphonomy of a unique tyrannosaurid bonebed from the upper Campanian Kaiparowits Formation of southern Utah: implications for tyrannosaurid gregariousness |journal=PeerJ |volume=9 |pages=e11013 |doi=10.7717/peerj.11013 |pmid=33976955 |pmc=8061582 | doi-access = free }}
• A metatarsal of juvenile tyrannosaurid theropod from the Dinosaur Park Formation of the Alberta, Canada, possibly referable to Daspletosaurus torosus was described by Yun (2021).{{cite journal| vauthors = Yun CG |title=A juvenile metatarsal of cf. Daspletosaurus torosus: Implications for ontogeny in tyrannosaurid theropods. |year=2021 |journal=Acta Palaeontologica Romaniae |volume=17 |issue=2 |pages=15–22 |doi=10.35463/j.apr.2021.02.02 |s2cid=237724062 |url=https://actapalrom.geo-paleontologica.org/Online_first/Yun_juvenileDaspletosaurus.pdf }}
• A study on the anatomy of the braincases of two specimens of Daspletosaurus is published by Paulina Carabajal et al. (2021).{{cite journal| vauthors = Paulina Carabajal A, Currie PJ, Dudgeon TW, Larsson HC, Miyashita T |title=Two braincases of Daspletosaurus (Theropoda: Tyrannosauridae): anatomy and comparison |journal=Canadian Journal of Earth Sciences |year=2021 |volume=58 |issue=9 |pages=885–910 |doi=10.1139/cjes-2020-0185 |doi-access=free }}
• A study aiming to calculate population variables such as abundance at any one time, species persistence and total number of individuals that ever lived for Tyrannosaurus rex is published by Marshall et al. (2021);{{cite journal | vauthors = Marshall CR, Latorre DV, Wilson CJ, Frank TM, Magoulick KM, Zimmt JB, Poust AW | title = Absolute abundance and preservation rate of Tyrannosaurus rex | journal = Science | volume = 372 | issue = 6539 | pages = 284–287 | date = April 2021 | pmid = 33859033 | doi = 10.1126/science.abc8300 | bibcode = 2021Sci...372..284M | s2cid = 233245062 }} the study is subsequently criticized by Meiri (2022).{{Cite journal|author=Meiri S |title=Population sizes of T. rex cannot be precisely estimated |year=2022 |journal=Frontiers of Biogeography |volume=14 |issue=2 |pages=e53781 |doi=10.21425/F5FBG53781 |s2cid=245288933 |doi-access=free }}{{Cite journal|vauthors=Marshall CR, Latorre DV, Wilson CJ, Frank TM, Magoulick KM, Zimmt JB, Poust AW |title=With what precision can the population size of Tyrannosaurus rex be estimated? A reply to Meiri |year=2022 |journal=Frontiers of Biogeography |volume=14 |issue=2 |pages=e55042 |doi=10.21425/F5FBG55042 |s2cid=245314491 |doi-access=free |hdl=10852/101238 |hdl-access=free }}
• A study aiming to estimate the natural frequency of the vertical swaying of the tail and the preferred walking speed and step frequency of Tyrannosaurus rex is published by van Bijlert, van Soest & Schulp (2021).{{cite journal | vauthors = van Bijlert PA, van Soest AJ, Schulp AS |year=2021 |title=Natural Frequency Method: estimating the preferred walking speed of Tyrannosaurus rex based on tail natural frequency |journal=Royal Society Open Science |volume=8 |issue=4 |pages=Article ID 201441 |doi=10.1098/rsos.201441 |pmid = 33996115 |pmc = 8059583 |bibcode=2021RSOS....801441V |s2cid=233312053 }}
• A study on the morphology of the neurovascular canal in the dentary of Tyrannosaurus rex is published by Kawabe & Hattori (2021).{{cite journal| vauthors = Kawabe S, Hattori S |title=Complex neurovascular system in the dentary of Tyrannosaurus |journal=Historical Biology |year=2022 |volume=34 |issue=7 |pages=1137–1145 |doi=10.1080/08912963.2021.1965137 |bibcode=2022HBio...34.1137K |s2cid=238728702 }}
• A study attempting to determine bite force of a juvenile Tyrannosaurus rex, based on mechanical tests designed to replicate bite marks attributed to juvenile specimens of this species, is published by Peterson, Tseng & Brink (2021).{{cite journal | vauthors = Peterson JE, Tseng ZJ, Brink S |year=2021 |title=Bite force estimates in juvenile Tyrannosaurus rex based on simulated puncture marks |journal=PeerJ |volume=9 |pages=e11450 |doi=10.7717/peerj.11450 |pmid=34141468 |pmc=8179241 |doi-access=free }}
• A study on the taphonomic and geochemical history of the Tyrannosaurus rex specimen MOR 1125 is published by Ullmann et al. (2021).{{cite journal| vauthors = Ullmann PV, Macauley K, Ash RD, Shoup B, Scannella JB |title=Taphonomic and Diagenetic Pathways to Protein Preservation, Part I: The Case of Tyrannosaurus rex Specimen MOR 1125 |year=2021 |journal=Biology |volume=10 |issue=11 |pages=Article 1193 |doi=10.3390/biology10111193 |pmid=34827186 |pmc=8614911 |doi-access=free }}
• A study on the anatomy of the postcranial skeleton and on the phylogenetic relationships of Pelecanimimus polyodon is published by Cuesta et al. (2021), who name a new clade Macrocheiriformes, defined as Pelecanimimus and all derived ornithomimosaurs.{{cite journal| vauthors = Cuesta E, Vidal D, Ortega F, Shibata M, Sanz JL |title=Pelecanimimus (Theropoda: Ornithomimosauria) postcranial anatomy and the evolution of the specialized manus in Ornithomimosaurs and sternum in maniraptoriforms |year=2021 |journal=Zoological Journal of the Linnean Society |volume=194 |issue=2 |pages=553–591 |doi=10.1093/zoolinnean/zlab013 }}
• New ornithomimid fossil material, providing new information on the distal tarsal morphology in ornithomimids, is described from the Campanian Kaiparowits Formation (Utah, United States) by Nottrodt & Farke (2021).{{cite journal | vauthors = Nottrodt RE, Farke AA | title = New data on the distal tarsals in Ornithomimidae | journal = Acta Palaeontologica Polonica | volume = 66 | issue = 4 | pages = 789–796 | year = 2021 | doi = 10.4202/app.00884.2021 | s2cid = 240011882 | doi-access = free }}
• A study on pelvic musculature in non-avian maniraptorans is published by Rhodes, Henderson & Currie (2021).{{cite journal | vauthors = Rhodes MM, Henderson DM, Currie PJ | title = Maniraptoran pelvic musculature highlights evolutionary patterns in theropod locomotion on the line to birds | journal = PeerJ | volume = 9 | pages = e10855 | year = 2021 | pmid = 33717681 | pmc = 7937347 | doi = 10.7717/peerj.10855 | doi-access = free }}
• A study on the neuroanatomy of a new alvarezsauroid skeleton in the collection of the Henan Geological Museum (China) is published by Agnolín et al. (2021).Federico L. Agnolín, Jun-Chang Lu, Martin Kundrát & Li Xu (2021) Alvarezsaurid osteology: new data on cranial anatomy, Historical Biology, {{doi|10.1080/08912963.2021.1929203}}
• A study on the skeletal anatomy, probable musculature and likely function of tails of alvarezsaurian theropods is published by Meso et al. (2021).{{cite journal| vauthors = Meso JG, Qin Z, Pittman M, Canale JI, Salgado L, Díaz VD |title=Tail anatomy of the Alvarezsauria (Theropoda, Coelurosauria), and its functional and behavioural implications |journal=Cretaceous Research |year=2021 |volume=124 |pages=Article 104830 |doi=10.1016/j.cretres.2021.104830 |bibcode=2021CrRes.12404830M |s2cid=233858300 }}
• A study on growth strategies and body miniaturization in the evolutionary history of alvarezsauroid theropods is published by Qin et al. (2021).{{cite journal | vauthors = Qin Z, Zhao Q, Choiniere JN, Clark JM, Benton MJ, Xu X | title = Growth and miniaturization among alvarezsauroid dinosaurs | journal = Current Biology | volume = 31 | issue = 16 | pages = 3687–3693.e5 | year = 2021 | doi = 10.1016/j.cub.2021.06.013 | pmid = 34233160 | s2cid = 235752037 | doi-access = free | bibcode = 2021CBio...31E3687Q }}
• A study on the osteology of Fukuivenator paradoxus is published by Hattori et al. (2021), who described previously undescribed elements and reinterpret this genus as a basal therizinosaur.{{Cite journal|vauthors=Hattori S, Kawabe S, Imai T, Shibata M, Miyata K, Xu X, Azuma Y|date=2021|title=Osteology of Fukuivenator paradoxus: A bizarre maniraptoran theropod from the Early Cretaceous of Fukui, Japan|url=https://www.dinosaur.pref.fukui.jp/archive/memoir/memoir020-001.pdf|journal=Memoir of the Fukui Prefectural Dinosaur Museum|volume=20|pages=1–82}}
• A study on the anatomy of the postcranial skeleton of Beipiaosaurus inexpectus is published by Liao et al. (2021).{{cite journal| vauthors = Liao CC, Zanno LE, Wang S, Xu X |title=Postcranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria) |year=2021 |journal=PLOS ONE |volume=16 |issue=9 |pages=e0257913 |doi=10.1371/journal.pone.0257913 |doi-access=free |pmid=34591927 |pmc=8483305 |bibcode=2021PLoSO..1657913L }}
• Reevaluation of putative blood cells preserved in the holotype specimen of Beipiaosaurus inexpectus is published by Korneisel et al. (2021), who interpret putative blood cells as more likely to be diagenetic structures.{{cite journal| vauthors = Korneisel DE, Nesbitt SJ, Werning S, Xiao S |year=2021 |title=Putative fossil blood cells reinterpreted as diagenetic structures |journal=PeerJ |volume=9 |pages=e12651 |doi=10.7717/peerj.12651 |pmid=35003935 |pmc=8684720 |doi-access=free |bibcode=2021PeerJ...912651K }}
• Reconstructions of the muscular system of the hindlimb, forelimb and the shoulder girdle of Nothronychus are presented by Smith (2021).{{cite journal | vauthors = Smith DK | title = Hind limb muscle reconstruction in the incipiently opisthopubic large therizinosaur Nothronychus (Theropoda; Maniraptora) | journal = Journal of Anatomy | volume = 238 | date = January 2021 | issue = 6 | pages = 1404–1424 | pmid = 33417263 | doi = 10.1111/joa.13382 | pmc = 8128771 }}{{cite journal | vauthors = Smith DK | title = Forelimb musculature and function in the therizinosaur Nothronychus (Maniraptora, Theropoda) | journal = Journal of Anatomy | volume = 239 | date = March 2021 | issue = 2 | pages = 307–335 | pmid = 33665832 | doi = 10.1111/joa.13418 | pmc = 8273597 | s2cid = 232124454 }}
• Zheng et al. (2021) study cellular and nuclear preservation in femoral articular cartilage of a specimen of Caudipteryx from the Yixian Formation (China).{{cite journal | vauthors = Zheng X, Bailleul AM, Li Z, Wang X, Zhou Z | title = Nuclear preservation in the cartilage of the Jehol dinosaur Caudipteryx | journal = Communications Biology | volume = 4 | issue = 1 | pages = Articles 1125 | year = 2021 | doi = 10.1038/s42003-021-02627-8 | pmid = 34561538 | pmc = 8463611 }}
• Partial skeleton of Elmisaurus rarus, preserving elements overlapping with known fossil material of Nomingia gobiensis, is described from the Upper Cretaceous Nemegt Formation (Mongolia) by Funston et al. (2021), who interpret this specimen as indicating that N. gobiensis is likely a junior synonym of E. rarus.{{cite journal| vauthors = Funston GF, Currie PJ, Tsogtbaatar C, Khishigjav T |title=A partial oviraptorosaur skeleton suggests low caenagnathid diversity in the Late Cretaceous Nemegt Formation of Mongolia |year=2021 |journal=PLOS ONE |volume=16 |issue=7 |pages=e0254564 |doi=10.1371/journal.pone.0254564 |pmid=34252154 |pmc=8274908 |bibcode=2021PLoSO..1654564F |doi-access=free }}
• A study on the body mass of Anzu wyliei is published by Atkins-Weltman, Snively & O'Connor (2021).{{cite journal| vauthors = Atkins-Weltman KL, Snively E, O'Connor P |year=2021 |title=Constraining the body mass range of Anzu wyliei (Theropoda: Caenagnathidae) using volumetric and extant–scaling methods |journal=Vertebrate Anatomy Morphology Palaeontology |volume=9 |pages=95–104 |doi=10.18435/vamp29375 |doi-access=free }}
• A caenagnathid metatarsal is described from the Campanian Mesaverde Formation (Wyoming, United States; representing the first record of a caenagnathid from this formation) by Yun & Funston (2021), who evaluate the implications of this specimen for the knowledge whether reported differences in metatarsal morphology between "Macrophalangia" and Chirostenotes were merely allometric in nature, or whether they might represent phylogenetically informative variation.{{cite journal| vauthors = Yun C, Funston GG |year=2021 |title=A caenagnathid oviraptorosaur metatarsal from the Mesaverde Formation (Campanian) of Wyoming, USA |journal=Vertebrate Anatomy Morphology Palaeontology |volume=9 |pages=105–115 |doi=10.18435/vamp29376 |doi-access=free }}
• An exceptionally preserved, articulated oviraptorid embryo, found inside an elongatoolithid egg in a posture previously unrecognized in a non-avian dinosaur but sharing aspects of bird-like tucking postures, is described from the Upper Cretaceous Hekou Formation (China) by Xing et al. (2021);{{cite journal | vauthors = Xing L, Niu K, Ma W, Zelenitsky DK, Yang TR, Brusatte SL | title = An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures | journal = iScience | volume = 25 | pages = Article 103516 | year = 2021 | issue = 1 | doi = 10.1016/j.isci.2021.103516 | pmid = 35106456 | pmc = 8786642 | s2cid = 245398552 }} however, the conclusions of the authors are subsequently contested by Deeming & Kundrát (2022), who argue that this specimen was not close to hatching, and that the positioning of its head relative to its body cannot bear any relationship to hatching position of this animal.{{cite journal| vauthors = Deeming DC, Kundrát M |title=Interpretation of fossil embryos requires reasonable assessment of developmental age |journal=Paleobiology |year=2022 |volume=49 |pages=68–76 |doi=10.1017/pab.2022.21 |s2cid=250938817 |doi-access=free }}
• Cau et al. (2021) report the identification of additional elements of the pectoral apparatus of the holotype specimen of Halszkaraptor escuilliei, including the furcula, and evaluate its implications for the knowledge of the evolution of the avian furcula.{{cite journal | vauthors = Cau A, Beyrand V, Barsbold R, Tsogtbaatar K, Godefroit P | title = Unusual pectoral apparatus in a predatory dinosaur resolves avian wishbone homology | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 14722 | year = 2021 | doi = 10.1038/s41598-021-94285-3 |pmid=34282248 |pmc=8289867 | bibcode = 2021NatSR..1114722C }}
• A study on the anatomy of the skeleton of Unenlagia comahuensis is published by Novas et al. (2021).{{cite journal | vauthors = Novas FE, Agnolín FL, Motta MJ, Brissón Egli F | title = Osteology of Unenlagia comahuensis (Theropoda, Paraves, Unenlagiidae) from the Late Cretaceous of Patagonia | journal = Anatomical Record | volume = 304 | issue = 12 | pages = 2741–2788 | date = April 2021 | pmid = 33894102 | doi = 10.1002/ar.24641 | s2cid = 233390123 | doi-access = free }}
• A study on the vertebral pneumaticity in Unenlagia comahuensis is published by Gianechini & Zurriaguz (2021).{{cite journal | vauthors = Gianechini FA, Zurriaguz VL |year=2021 |title=Vertebral pneumaticity of the paravian theropod Unenlagia comahuensis, from the Upper Cretaceous of Patagonia, Argentina |journal=Cretaceous Research |volume=127 |pages=Article 104925 |doi=10.1016/j.cretres.2021.104925 |bibcode=2021CrRes.12704925G }}
• Description of a new troodontid specimen from the Upper Cretaceous Wulansuhai Formation (China), and a study on the phylogenetic relationships and evolutionary history of the Late Cretaceous troodontids, is published by Wang et al. (2021).{{cite journal | vauthors = Wang S, Zhang Q, Tan Q, Jiangzuo Q, Zhang H, Tan L |year=2021 |title=New troodontid theropod specimen from Inner Mongolia, China clarifies phylogenetic relationships of later-diverging small-bodied troodontids and paravian body size evolution |journal=Cladistics |volume=38 |issue=1 |pages=59–82 |doi=10.1111/cla.12467 |pmid=35049080 |s2cid=237738013 }}
• A unique troodontid nest is described by Maipig et al. (2021), preserving a unique spiral pattern of eggs embedded vertically into substrate.{{Cite journal |author=Qian Maiping |author2=Duan Zheng |author3=Ma Xue |author4=Chen Rong |author5=Zhang Xiang |author6=Yu Minggang |author7=Zhao Qian|date=2021|title=A Cretaceous troodontid laid her pairs of eggs vertically and arranged spirally in a nest|url=http://open.oriprobe.com/articles/61668056/A_Cretaceous_troodontid_laid_her_pairs_of_eggs_ver.htm?fbclid=IwAR12HbRxV4Uw4MnVDMLzTQFEu0oyTMXGdBNmG7V5OU9mGo04mQbJ-Z3hjoA|journal=Jiangsu Geology|volume=2|pages=138–142}}
• Multi-individual aggregates of mammal skeletons are described from the Upper Cretaceous Two Medicine Formation (Montana, United States) by Freimuth et al. (2021), who interpret these aggregates as the oldest known mammal-bearing regurgitalites, probably produced by Troodon formosus.{{cite journal| vauthors = Freimuth WJ, Varricchio DJ, Brannick AL, Weaver LN, Wilson Mantilla GP |year=2021 |title=Mammal-bearing gastric pellets potentially attributable to Troodon formosus at the Cretaceous Egg Mountain locality, Two Medicine Formation, Montana, USA |journal=Palaeontology |volume=64 |issue=5 |pages=699–725 |doi=10.1111/pala.12546 |bibcode=2021Palgy..64..699F |s2cid=237659529 }}
• A study on the anatomy and phylogenetic relationships of Borogovia gracilicrus is published by Cau & Madzia (2021).{{cite journal| vauthors = Cau A, Madzia D |year=2021 |title=The phylogenetic affinities and morphological peculiarities of the bird-like dinosaur Borogovia gracilicrus from the Upper Cretaceous of Mongolia |journal=PeerJ |volume=9 |pages=e12640 |doi=10.7717/peerj.12640 |pmid=34963824 |pmc=8656384 |doi-access=free }}
• Brown, Tanke & Hone (2021) describe a hadrosaurid bone from the Campanian Dinosaur Park Formation (Alberta, Canada) preserved with bite marks produced by a small- to medium-sized theropod dinosaur, deviating from the majority of known theropod tooth marks and indicative of a behavior similar to mammalian gnawing.{{cite journal | vauthors = Brown CM, Tanke DH, Hone DW | title = Rare evidence for 'gnawing-like' behavior in a small-bodied theropod dinosaur | journal = PeerJ | volume = 9 | pages = e11557 | year = 2021 | doi = 10.7717/peerj.11557 | pmid = 34221716 | pmc = 8234920 | doi-access = free }}
• Revision of the biodiversity of theropods from the Dinosaur Park Formation is published by Cullen et al. (2021).{{cite journal| vauthors = Cullen TM, Zanno L, Larson DW, Todd E, Currie PJ, Evans DC |title=Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation |journal=Canadian Journal of Earth Sciences |year=2021 |volume=58 |issue=9 |pages=870–884 |doi=10.1139/cjes-2020-0145 }}
• Exquisitely preserved, ornamented partial eggs with theropod affinities, representing some of the smallest Mesozoic eggs reported to date, are described from the Campanian Kaiparowits Formation (Utah, United States) by Oser et al. (2021), who name a new ootaxon Stillatuberoolithus storrsi.{{cite journal | vauthors = Oser SE, Chin K, Sertich JJ, Varricchio DJ, Choi S, Rifkin J | title = Tiny, ornamented eggs and eggshell from the Upper Cretaceous of Utah represent a new ootaxon with theropod affinities | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 10021 | year = 2021 | doi = 10.1038/s41598-021-89472-1 | pmid = 33976315 | pmc = 8113451 | bibcode = 2021NatSR..1110021O }}
• Sennikov (2021) conclude that therizinosaurids had a plantigrade stance based on their overall foot anatomy and reanalysis of the ichnogenus Macropodosaurus, and reinterpret the ichnotaxon Batrachopus grandis from the Lower Cretaceous Jinju Formation and Haman Formation (South Korea), formerly suggested to be made by bipedal crocodylomorphs, as probable therizinosaur tracks based on comparison with Macropodosaurus.{{cite journal|last1=Sennikov|first1=A. G.|date=2021|title=The Plantigrade Segnosaurians: Sloth Dinosaurs or Bear Dinosaurs?|journal=Paleontological Journal|volume=55|issue=7|pages=1158–1185|doi=10.1134/S0031030121100087|bibcode=2021PalJ...55.1158S |s2cid=245539994}}

• Review of the diversity and composition of South American sauropodomorph faunas throughout the Late Triassic is published by Pol et al. (2021).{{cite journal| vauthors = Pol D, Otero A, Apaldetti C, Martínez RN |year=2021 |title=Triassic sauropodomorph dinosaurs from South America: The origin and diversification of dinosaur dominated herbivorous faunas |journal=Journal of South American Earth Sciences |volume=107 |pages=Article 103145 |doi=10.1016/j.jsames.2020.103145 |bibcode=2021JSAES.10703145P |s2cid=233579282 }}
• A study on the evolution of the olfactory system in sauropodomorph dinosaurs, as indicated by the ratio between the size of the olfactory bulbs and cerebral hemispheres in sauropodomorph endocasts, is published by Müller (2021).{{cite journal| vauthors = Müller RT |year=2021 |title=Olfactory acuity in early sauropodomorph dinosaurs |journal=Historical Biology |volume=34 |issue=2 |pages=346–351 |doi=10.1080/08912963.2021.1914600 |s2cid=234821131 }}
• A study on the timing of the earliest occurrence of Triassic sauropodomorphs in their northernmost range (Fleming Fjord Formation, Greenland), and on possible relationship between climate changes and early sauropodomorph dispersal to the temperate belt of the Northern Hemisphere, is published by Kent & Clemmensen (2021).{{cite journal | vauthors = Kent DV, Clemmensen LB | title = Northward dispersal of dinosaurs from Gondwana to Greenland at the mid-Norian (215-212 Ma, Late Triassic) dip in atmospheric pCO₂ | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 118 | issue = 8 | pages = e2020778118 | date = February 2021 | pmid = 33593914 | pmc = 7923678 | doi = 10.1073/pnas.2020778118 | bibcode = 2021PNAS..11820778K | doi-access = free }}
• Probable tracks of large sauropodomorphs dinosaurs, potentially representing the largest known tracks belonging to the ichnogenus Eosauropus reported to date, are described from the Upper Triassic (likely Rhaetian) Blue Anchor Formation (Penarth, south Wales, United Kingdom) by Falkingham et al. (2021).{{cite journal | vauthors = Falkingham PL, Maidment SC, Lallensack JN, Martin JE, Suan G, Cherns L, Howells C, Barrett PM | title = Late Triassic dinosaur tracks from Penarth, south Wales | journal = Geological Magazine | volume = 159 | year = 2021 | issue = 6 | pages = 821–832 | doi = 10.1017/S0016756821001308 | s2cid = 245586628 | doi-access = free }}
• A study on the evolution of the morphological diversity of sauropodomorph dinosaurs is published by Apaldetti et al. (2021).{{cite journal | vauthors = Apaldetti C, Pol D, Ezcurra MD, Martínez RN | title = Sauropodomorph evolution across the Triassic–Jurassic boundary: body size, locomotion, and their influence on morphological disparity | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 22534 | year = 2021 | doi = 10.1038/s41598-021-01120-w | pmid = 34795322 | pmc = 8602272 | bibcode = 2021NatSR..1122534A |doi-access=free }}
• New skull material of Plateosaurus, including the first two juvenile skulls of members of this genus, is described from the locality of Frick (Switzerland) by Lallensack et al. (2021), who attempt to determine whether the locality of Frick and German localities of Trossingen and Halberstadt contain specimens of Plateosaurus belonging to a single species.{{cite journal| vauthors = Lallensack JN, Teschner EM, Pabst B, Sander PM |title=New skulls of the basal sauropodomorph Plateosaurus trossingensis from Frick, Switzerland: Is there more than one species? |year=2021 |journal=Acta Palaeontologica Polonica |volume=66 |issue=1 |pages=1–28 |doi=10.4202/app.00804.2020 |s2cid=233264515 |doi-access=free }}
• A study on the skeletal growth during the ontogeny in Massospondylus carinatus is published by Chapelle, Botha & Choiniere (2021).{{cite journal| vauthors = Chapelle KE, Botha J, Choiniere JN |year=2021 |title=Extreme growth plasticity in the early branching sauropodomorph Massospondylus carinatus |journal=Biology Letters |volume=17 |issue=5 |pages=Articles ID 20200843 |doi=10.1098/rsbl.2020.0843 |pmid=33975484 |pmc=8113909 }}
• A study on the age of the fossil material of Yunnanosaurus youngi is published by Ren et al. (2021).{{cite journal| vauthors = Ren XX, Su X, Wang GF, You HL |year=2021 |title=Sedimentological evidence suggests an Early Jurassic age for Yunnanosaurus youngi (Dinosauria: Sauropodomorpha) in Yunnan Province of China |journal=Historical Biology |volume=34 |issue=9 |pages=1827–1833 |doi=10.1080/08912963.2021.1984445 |s2cid=244227159 }}
• A study on the cranial anatomy of Anchisaurus polyzelus and the development of cranial characters in sauropodomorph ontogeny is published by Fabbri et al. (2021){{cite journal | vauthors = Fabbri M, Navalón G, Mongiardino Koch N, Hanson M, Petermann H, Bhullar BA | title = A shift in ontogenetic timing produced the unique sauropod skull | journal = Evolution; International Journal of Organic Evolution | volume = 75 | issue = 4 | pages = 819–831 | date = April 2021 | pmid = 33578446 | doi = 10.1111/evo.14190 | s2cid = 231909592 }}
• An assemblage including over 100 eggs and skeletal specimens of 80 specimens of Mussaurus patagonicus, ranging from embryos to fully-grown adults, is described from the Laguna Colorada Formation (Argentina) by Pol et al. (2021), who assign an Early Jurassic (Sinemurian) maximum age for the Mussaurus bearing sediments, and interpret this assemblage as likely evidence of colonial nesting habits, presence of social cohesion throughout the different stages of the lifespan, and age-based social partitioning within a herd structure in Mussaurus.{{cite journal| vauthors = Pol D, Mancuso AC, Smith RM, Marsicano CA, Ramezani J, Cerda IA, Otero A, Fernandez V |title=Earliest evidence of herd-living and age segregation amongst dinosaurs |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 20023 |doi=10.1038/s41598-021-99176-1 | doi-access = free |pmid=34675327 |pmc=8531321 |bibcode=2021NatSR..1120023P }}
• An extensive Late Jurassic sauropod tracksite, preserving the longest continuous sequence of sauropod pes prints reported to date and representing a rare record of a >180° turn made by the sauropod trackmaker to completely change direction and cross its own trackway, is described from a high altitude locality near Ouray (Colorado, United States) by Goodell et al. (2021).{{cite journal| vauthors = Goodell Z, Lockley MG, Lucas SG, Schumacher BA, Smith JA, Trujillo R, Xing L |year=2021 |title=A high-altitude sauropod trackway site in the Jurassic of Colorado: The longest known consecutive footprint sequence reveals evidence of sharp turning behavior |journal=New Mexico Museum of Natural History and Science Bulletin |volume=82 |pages=101–112 }}
• A study on the anatomy of the axial skeleton of Bagualia alba is published by Gomez, Carballido & Pol (2021).{{cite journal| vauthors = Gomez KL, Carballido JL, Pol D |title=The axial skeleton of Bagualia alba (Dinosauria: Eusauropoda) from the Early Jurassic of Patagonia |year=2021 |journal=Palaeontologia Electronica |volume=24 |issue=3 |pages=Article number 24.3.37A |doi=10.26879/1176 |doi-access=free |hdl=11336/166827 |hdl-access=free }}
• New fossil material of Shunosaurus, providing new information on the development of the skeleton of this sauropod during its ontogeny, is described from the Middle Jurassic Shaximiao Formation (China) by Ma et al. (2021).{{cite journal| vauthors = Ma Q, Dai H, Tan C, Li N, Wang P, Ren X, Meng L, Zhao Q, Wei G, Xu X |year=2021 |title=New Shunosaurus (Dinosauria: Sauropoda) material from the Middle Jurassic lower Shaximiao Formation of Yunyang, Chongqing, China |journal=Historical Biology |volume=34 |issue=6 |pages=1085–1099 |doi=10.1080/08912963.2021.1962852 |s2cid=238657458 }}
• A study on the skeletal anatomy of the holotype of Patagosaurus fariasi is published by Holwerda, Rauhut & Pol (2021).{{cite journal| vauthors = Holwerda FM, Rauhut OW, Pol D |year=2021 |title=Osteological revision of the holotype of the Middle Jurassic sauropod dinosaur Patagosaurus fariasi Bonaparte, 1979 (Sauropoda: Cetiosauridae) |journal=Geodiversitas |volume=43 |issue=16 |pages=575–643 |doi=10.5252/geodiversitas2021v43a16 |s2cid=237537773 |url=https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/43/16 |doi-access=free }}
• A new specimen of Haplocanthosaurus with expanded neural canals is described by Wedel et al. (2021).{{cite journal| vauthors= Wedel M, Atterholt J, Dooley Jr AC, Farooq S, Macalino J, Nalley TK, Wisser G, Yasmer J |year=2021 |title=Expanded neural canals in the caudal vertebrae of a specimen of Haplocanthosaurus |journal=Academia Letters |doi=10.20935/AL911|s2cid=236690010 }}
• A study on the anatomy and phylogenetic relationships of Amphicoelias altus is published by Mannion, Tschopp & Whitlock (2021).{{cite journal| vauthors = Mannion PD, Tschopp E, Whitlock JA |year=2021 |title=Anatomy and systematics of the diplodocoid Amphicoelias altus supports high sauropod dinosaur diversity in the Upper Jurassic Morrison Formation of the USA |journal=Royal Society Open Science |volume=8 |issue=6 |pages=Article ID 210377 |doi=10.1098/rsos.210377 |pmid=34150318 |pmc=8206699 |bibcode=2021RSOS....810377M }}
• The paleohistology of two dicraeosaurids from the La Amarga Formation (Argentina) is studied by Winholdz and Cerda (2021), who find that the holotype specimen of Amargatitanis macni belonged to a more mature individual than the holotype of Amargasaurus cazaui.{{Cite journal|vauthors = Windholz GJ, Cerda IA|title=Paleohistology of two dicraeosaurid dinosaurs (Sauropoda; Diplodocoidea) from La Amarga Formation (Barremian–Aptian, Lower Cretaceous), Neuquén Basin, Argentina: Paleobiological implications|journal=Cretaceous Research|volume=128|pages=Article 104965|year=2021|doi=10.1016/j.cretres.2021.104965 |bibcode=2021CrRes.12804965W |issn=0195-6671}}
• Fossilized skin of a juvenile member of the genus Diplodocus, providing evidence of new scale shapes and patterns never before seen in diplodocids, is described from the Mother's Day Quarry (Bighorn Basin, Montana, United States) by Gallagher, Poole & Schein (2021).{{cite journal | vauthors = Gallagher T, Poole J, Schein JP | title = Evidence of integumentary scale diversity in the Late Jurassic sauropod Diplodocus sp. from the Mother's Day Quarry, Montana | journal = PeerJ | volume = 9 | pages = e11202 | year = 2021 | doi = 10.7717/peerj.11202 |pmid=33986987 |pmc=8098675 | doi-access = free }}
• A study on the anatomy of the braincase of a diplodocid sauropod (possibly Leinkupal laticauda) from the Lower Cretaceous Bajada Colorada Formation (Argentina) is published by Garderes et al. (2021; final version published in 2022).{{Cite journal|vauthors = Garderes JP, Gallina PA, Whitlock JA, Toledo N |title=Neuroanatomy of a diplodocid sauropod dinosaur from the Lower Cretaceous of Patagonia, Argentina |journal=Cretaceous Research |volume=129 |pages=Article 105024 |year=2022 |doi=10.1016/j.cretres.2021.105024 |bibcode=2022CrRes.12905024G |s2cid=239658409 }}
• Redescription of the anatomy of the braincase of Limaysaurus tessonei is published by Paulina-Carabajal & Calvo (2021).{{cite journal | vauthors = Paulina-Carabajal A, Calvo JO | title = Re-description of the braincase of the rebbachisaurid sauropod Limaysaurus tessonei and novel endocranial information based on CT scans | journal = Anais da Academia Brasileira de Ciências | volume = 93 | issue = suppl 2 | pages = e20200762 | year = 2021 | pmid = 33533794 | doi = 10.1590/0001-3765202120200762 | s2cid = 231790118 | doi-access = free | hdl = 11336/183721 | hdl-access = free }}
• A description of well preserved fossil material of Camarasaurus, including an articulated, nearly-complete skull, and an analysis of variability within the genus based on cranial allometry trends is published by Woodruff et al. (2021).{{cite journal| vauthors = Woodruff DC, Wilhite DR, Larson PL, Eads M |year=2021 |title=A new specimen of the basal macronarian Camarasaurus (Dinosauria: Sauropoda) highlights variability and cranial allometry within the genus |journal=Volumina Jurassica|volume=19 |pages=109–130 |doi=10.7306/VJ.19.5 |url=https://vjs.pgi.gov.pl/article/view/33111/24263 | doi-access = free}}
• Partial sauropod maxilla, possibly belonging to a brachiosaurid, is described from the Cretaceous (Albian–Cenomanian) Longjing Formation (northeast China) by Liao et al. (2021).{{cite journal| vauthors = Liao C, Moore A, Jin C, Yang T, Shibata M, Jin F, Wang B, Jin D, Guo Y, Xu X |year=2021 |title=A possible brachiosaurid (Dinosauria, Sauropoda) from the mid-Cretaceous of northeastern China |journal=PeerJ |volume=9 |pages=e11957 |doi=10.7717/peerj.11957 |pmid=34484987 |pmc=8381880 |doi-access=free }}
• Sauropod tracks probably produced by non-titanosaurian titanosauriforms are described from the Rupelo Formation (Spain) by Torcida Fernández-Baldor et al. (2021), who evaluate the paleoenvironmental and paleoecological implications of this finding, and name a new ichnotaxon Iniestapodus burgensis.{{cite journal| vauthors = Torcida Fernández-Baldor F, Díaz-Martínez I, Huerta P, Montero Huerta D, Castanera D |title=Enigmatic tracks of solitary sauropods roaming an extensive lacustrine megatracksite in Iberia |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 16939 |doi=10.1038/s41598-021-95675-3 |pmid=34417474 |pmc=8379178 |bibcode=2021NatSR..1116939T | doi-access = free }}
• A study on tooth replacement rates in early somphospondylans, as indicated by data from a dentary from the Lower Cretaceous (Aptian–Albian) Haoling Formation (China), is published by Chang et al. (2021).{{cite journal| vauthors = Chang H, You H, Xu L, Ma W, Gao D, Jia S, Xia M, Zhang J, Li Y, Wang X, Liu D, Li J, Zhang J, Yang L, Wei X |title=Relatively low tooth replacement rate in a sauropod dinosaur from the Early Cretaceous Ruyang Basin of central China |year=2021 |journal=PeerJ |volume=9 |pages=e12361 |doi=10.7717/peerj.12361 |pmid=34760377 |pmc=8556709 | doi-access = free }}
• A study aiming to determine whether titanosaur osteoderms could act as defensive structures is published by Silva Junior et al. (2021; final version published in 2022).{{cite journal | vauthors = Silva Junior JC, Montefeltro FC, Marinho TS, Martinelli AG, Langer MC |title=Finite elements analysis suggests a defensive role for osteoderms in titanosaur dinosaurs (Sauropoda) |journal=Cretaceous Research |year=2022 |volume=129 |pages=Article 105031 |doi=10.1016/j.cretres.2021.105031 |bibcode=2022CrRes.12905031S |s2cid=239121820 }}
• Description of the anatomy of the referred specimen of Diamantinasaurus matildae and a study on the phylogenetic relationships of this species is published by Poropat et al. (2021), who name a new clade Diamantinasauria, which includes it alongside Savannasaurus and Sarmientosaurus.{{cite journal| vauthors = Poropat SF, Kundrát M, Mannion PD, Upchurch P, Tischler TR, Elliott DA |title=Second specimen of the Late Cretaceous Australian sauropod dinosaur Diamantinasaurus matildae provides new anatomical information on the skull and neck of early titanosaurs |year=2021 |journal=Zoological Journal of the Linnean Society |volume=192 |issue=2 |pages=610–674 |doi=10.1093/zoolinnean/zlaa173 |doi-access=free }}
• Fossil material of a giant titanosaur sauropod, distinct from Andesaurus and probably exceeding Patagotitan in size, is described from the Cenomanian Candeleros Formation (Argentina) by Otero et al. (2021).{{cite journal | vauthors = Otero A, Carballido JL, Salgado L, Canudo JI, Garrido AC |title=Report of a giant titanosaur sauropod from the Upper Cretaceous of Neuquén Province, Argentina |journal=Cretaceous Research |date=12 January 2021 |volume=122 |pages=104754 |doi=10.1016/j.cretres.2021.104754 |bibcode=2021CrRes.12204754O |s2cid=233582290 }}
• Revision of known fossil material of Pellegrinisaurus powelli and a study on the skeletal anatomy, bone histology and phylogenetic relationships of this sauropod are published by Cerda et al. (2021).{{cite journal | vauthors = Cerda I, Zurriaguz VL, Carballido JL, González R, Salgado L |title=Osteology, paleohistology and phylogenetic relationships of Pellegrinisaurus powelli (Dinosauria: Sauropoda) from the Upper Cretaceous of Argentinean Patagonia |journal=Cretaceous Research |year=2021 |volume=128 |pages=104957 |doi=10.1016/j.cretres.2021.104957 |bibcode=2021CrRes.12804957C }}
• New titanosaur remains, possibly belonging to a member of Colossosauria distinct from previously known taxa, are described from the Upper Cretaceous Portezuelo Formation (Argentina) by Bellardini et al. (2021).{{cite journal| vauthors = Bellardini F, Windholz GJ, Baiano MA, Garrido AC, Filippi L |year=2021 |title=New titanosaur remains from the Portezuelo Formation (Turonian–Coniancian) and their implications for the sauropod faunal diversity of the southern Neuquén Basin, Patagonia, Argentina |journal=Journal of South American Earth Sciences |volume=111 |pages=Article 103457 |doi=10.1016/j.jsames.2021.103457 |bibcode=2021JSAES.11103457B }}
• A study on the anatomy of the axial skeleton of Rinconsaurus caudamirus is published by Pérez Moreno et al. (2021).{{cite journal| vauthors = Pérez Moreno A, Carballido JL, Otero A, Salgado L, Calvo JO |year=2021 |title=The axial skeleton of Rinconsaurus caudamirus (Sauropoda: Titanosauria) from the Late Cretaceous of Patagonia, Argentina |journal=Ameghiniana |volume=59 |issue=1 |pages=1–46 |doi=10.5710/AMGH.13.09.2021.3427 |issn=0002-7014 |s2cid=240592543 }}
• A study on the composition of several gastroliths from the Morrison are published by Malone, Strasser, Malone, D'Emic, Brown, and Craddock, who point to the differences between them and the surrounding rock and similarities to another site 1,000 km eastwards to suggest evidence of migration in sauropod dinosaurs.{{cite journal| vauthors = Malone JR, Strasser JC, Malone DH, D'Emic MD, Brown L, Craddock JP |year=2021|title=Jurassic dinosaurs on the move: Gastrolith provenance and long-distance migration|url=|journal=Terra Nova|language=en|volume=33|issue=4|pages=375–382|doi=10.1111/ter.12522|bibcode=2021TeNov..33..375M |s2cid=233901940|issn=1365-3121}}
• Description of new fossil material and a study on the phylogenetic relationships of Tengrisaurus starkovi is published by Averianov, Sizov & Skutschas (2021).{{cite journal| vauthors = Averianov AO, Sizov AV, Skutschas PP |year=2021 |title=Gondwanan affinities of Tengrisaurus, Early Cretaceous titanosaur from Transbaikalia, Russia (Dinosauria, Sauropoda) |journal=Cretaceous Research |volume=122 |pages=Article 104731 |doi=10.1016/j.cretres.2020.104731 |bibcode=2021CrRes.12204731A |s2cid=233539964 }}
• Aureliano et al. (2021) report preservation of histological structure related to an avian-like air sac system in a vertebra of a saltasaurid titanosaur from the Upper Cretaceous São José do Rio Preto Formation (Bauru Group, Brazil).{{cite journal | vauthors = Aureliano T, Ghilardi AM, Navarro BA, Fernandez MA, Ricardi-Branco F, Wedel MJ | title = Exquisite air sac histological traces in a hyperpneumatized nanoid sauropod dinosaur from South America | journal = Scientific Reports | volume = 11 | issue = 1 | pages = Article number 24207 | year = 2021 | doi = 10.1038/s41598-021-03689-8 | pmid = 34921226 | pmc = 8683417 | bibcode = 2021NatSR..1124207A | doi-access = free }}
• Evidence of the preservation of nitrogen-bearing organic molecules (identified as proteinaceous moieties) in titanosaur eggshell from the Maastrichtian Lameta Formation (India) is presented by Dhiman et al. (2021).{{cite journal| vauthors = Dhiman H, Dutta S, Kumar S, Verma V, Prasad G |year=2021 |title=Discovery of proteinaceous moieties in Late Cretaceous dinosaur eggshell |journal=Palaeontology |volume=64 |issue=5 |pages=585–595 |doi=10.1111/pala.12565 |bibcode=2021Palgy..64..585D |doi-access=free }}
• A study on the stable isotope compositions of titanosaurian eggshells, bone and an associated tooth sampled in three Late Cretaceous nesting sites from La Rioja Province (Argentina), evaluating their implications for the knowledge of the body temperature of titanosaur sauropods, their diet, and the environmental conditions they needed reproduce, is published by Leuzinger et al. (2021).{{cite journal | vauthors = Leuzinger L, Bernasconi SM, Vennemann T, Luz Z, Vonlanthen P, Ulianov A, Baumgartner-Mora C, Hechenleitner EM, Fiorelli LE, Alasino PH |title=Life and reproduction of titanosaurians: Isotopic hallmark of mid-palaeolatitude eggshells and its significance for body temperature, diet, and nesting |journal=Chemical Geology |year=2021 |volume=583 |pages=Article 120452 |doi=10.1016/j.chemgeo.2021.120452 |bibcode=2021ChGeo.58320452L |s2cid=237674699 |url=https://serval.unil.ch/resource/serval:BIB_067AC096360A.P001/REF.pdf }}

• Revision of the phylogenetic nomenclature of ornithischian dinosaurs is published by Madzia et al. (2021), who name new clades Corythosauria, Euceratopsia, Saphornithischia, Panoplosaurini and Struthiosaurini.{{cite journal | vauthors = Madzia D, Arbour VM, Boyd CA, Farke AA, Cruzado-Caballero P, Evans DC | title = The phylogenetic nomenclature of ornithischian dinosaurs | journal = PeerJ | volume = 9 | pages = e12362 | year = 2021 | doi = 10.7717/peerj.12362 | pmid = 34966571 | pmc = 8667728 | doi-access = free }}
• New fossil material of ornithischians, including remains of basal euiguanodontian and hadrosaurid ornithopods and the southernmost record of ankylosaurs from South America reported to date, is described from the Upper Cretaceous (Campanian–Maastrichtian) Chorrillo Formation (Argentina) by Rozadilla et al. (2021), who evaluate the implications of these fossils for the knowledge of the evolutionary history of ankylosaurs and hadrosaurids in South America.{{cite journal| vauthors = Rozadilla S, Agnolín F, Manabe M, Tsuihiji T, Novas FE |year=2021 |title=Ornithischian remains from the Chorrillo Formation (Upper Cretaceous), southern Patagonia, Argentina, and their Implications on ornithischian paleobiogeography in the southern hemisphere |journal=Cretaceous Research |volume=125 |pages=Article 104881 |doi=10.1016/j.cretres.2021.104881 |bibcode=2021CrRes.12504881R }}
• A study on the Late Cretaceous ornithischian assemblage of western North America, aiming to examine the prediction that juveniles of large herbivores competitively excluded small herbivorous species, and that the small species that were able to coexist alongside the juveniles of larger species did so because of their unique occupation of niche space, is published by Wyenberg-Henzler, Patterson & Mallon (2021).{{cite journal| vauthors = Wyenberg-Henzler T, Patterson RT, Mallon JC |title=Size-mediated competition and community structure in a Late Cretaceous herbivorous dinosaur assemblage |journal=Historical Biology |year=2022 |volume=34 |issue=11 |pages=2230–2240 |doi=10.1080/08912963.2021.2010191 |s2cid=245063636 |doi-access=free |bibcode=2022HBio...34.2230W }}
• Radermacher et al. (2021) describe a new, fully articulated skeleton of Heterodontosaurus tucki, preserving a suite of novel postcranial features unknown in any other ornithischian dinosaur, and evaluate the implications of this specimen for the knowledge of the evolution of ornithischian respiratory biology.{{cite journal| vauthors = Radermacher VJ, Fernandez V, Schachner ER, Butler RJ, Bordy EM, Hudgins MN, de Klerk WJ, Chapelle KE, Choiniere JN |title=A new Heterodontosaurus specimen elucidates the unique ventilatory macroevolution of ornithischian dinosaurs |journal=eLife |year=2021 |volume=10 |pages=e66036 |doi=10.7554/eLife.66036 |pmid=34225841 |pmc=8260226 |doi-access=free }}

• A study on the skeletal anatomy and bone histology of Scutellosaurus lawleri, providing new data on the morphology and new life reconstruction for this dinosaur, is published by Breeden et al. (2021).{{cite journal| vauthors = Breeden BT, Raven TJ, Butler RJ, Rowe TB, Maidment SC |year=2021 |title=The anatomy and palaeobiology of the early armoured dinosaur Scutellosaurus lawleri (Ornithischia: Thyreophora) from the Kayenta Formation (Lower Jurassic) of Arizona |journal=Royal Society Open Science |volume=8 |issue=7 |pages=Article ID 201676 |doi=10.1098/rsos.201676 |pmid=34295511 |pmc=8292774 |bibcode=2021RSOS....801676B }}
• A stegosaurian humerus is described from the Cañadón Calcáreo Formation (Argentina) by Rauhut, Carballido & Pol (2021), extending the fossil record of Stegosauria to the Late Jurassic of South America.{{cite journal| vauthors = Rauhut OW, Carballido JL, Pol D |year=2021 |title=First Osteological Record of a Stegosaur (Dinosauria, Ornithischia) from the Upper Jurassic of South America |journal=Journal of Vertebrate Paleontology |volume=40 |issue=6 |pages=e1862133 |doi=10.1080/02724634.2020.1862133 |s2cid=234161169 }}
• A study on the morphology, macro- and microwear, and microanatomy of the stegosaur teeth from the Teete locality (Lower Cretaceous Batylykh Formation; Sakha, Russia), evaluating their implications for the knowledge of the paleobiology of the Teete stegosaur, is published by Skutschas et al. (2021).{{cite journal | vauthors = Skutschas PP, Gvozdkova VA, Averianov AO, Lopatin AV, Martin T, Schellhorn R, Kolosov PN, Markova VD, Kolchanov VV, Grigoriev DV, Kuzmin IT, Vitenko DD | display-authors = 6 | title = Wear patterns and dental functioning in an Early Cretaceous stegosaur from Yakutia, Eastern Russia | journal = PLOS ONE | volume = 16 | issue = 3 | pages = e0248163 | year = 2021 | pmid = 33730093 | pmc = 7968641 | doi = 10.1371/journal.pone.0248163 | bibcode = 2021PLoSO..1648163S | doi-access = free }}
• The smallest stegosaur track reported to date, co-occurring with the tracks of larger individuals, is described from the Lower Cretaceous Tugulu Group (Xinjiang, China) by Xing et al. (2021).{{cite journal| vauthors = Xing L, Lockley MG, PERSONS IV WS, Klein H, Romilio A, Wang D, Wang M |title=Stegosaur track assemblage from Xinjiang, China, featuring the smallest known stegosaur record |year=2021 |journal=PALAIOS |volume=36 |issue=2 |pages=68–76 |doi=10.2110/palo.2020.036 |bibcode=2021Palai..36...68X |s2cid=233129489 }}
• The type locality and holotype of Dracopelta zbyszewskii are reinterpreted by Russo & Mateus (2021), who also chronicle the history of the holotype.{{cite journal|vauthors= Russo J, Mateus O|title=History of the discovery of the ankylosaur Dracopelta zbyszewskii (Upper Jurassic), with new data about the type specimen and its locality|journal=Comunicações Geológicas|date=November 2021|volume=108|issue=1|pages=27–34|doi=10.34637/dmdm-5w12|url=https://www.lneg.pt/wp-content/uploads/2021/12/CG21-04-1305_Russo-e-Mateus.pdf}}
• Riguetti et al. (2021) describe nodosaurid tracks from the Maastrichtian El Molino Formation (Bolivia), increasing known diversity of ankylosaur tracks from South America.{{cite journal| vauthors = Riguetti F, Citton P, Apesteguía S, Zacarías GG, Pereda-Suberbiola X |title=New ankylosaurian trackways (cf. Tetrapodosaurus) from an uppermost Cretaceous level of the El Molino Formation of Bolivia |year=2021 |journal=Cretaceous Research |volume=124 |pages=Article 104810 |doi=10.1016/j.cretres.2021.104810 |bibcode=2021CrRes.12404810R |s2cid=233815474 }}
• Several fragmentary skulls and skull elements of Hungarosaurus, providing new information on the morphological diversity, development and possible function of the ornamentation of nodosaurid skulls, are described by Ősi et al. (2021).{{cite journal | vauthors = Ősi A, Magyar J, Rosta K, Vickaryous M | title = Cranial ornamentation in the Late Cretaceous nodosaurid ankylosaur Hungarosaurus | journal = PeerJ | volume = 9 | pages = e11010 | year = 2021 | pmid = 33717709 | pmc = 7936564 | doi = 10.7717/peerj.11010 | doi-access = free }}
• A study on dental microwear and jaw movement of Jinyunpelta, and on its implications for the knowledge of the evolution of the feeding mechanism of ankylosaurids, is published by Kubo et al. (2021).{{cite journal | vauthors = Kubo T, Zheng W, Kubo MO, Jin X | title = Dental microwear of a basal ankylosaurine dinosaur, Jinyunpelta and its implication on evolution of chewing mechanism in ankylosaurs | journal = PLOS ONE | volume = 16 | issue = 3 | pages = e0247969 | year = 2021 | pmid = 33690686 | pmc = 7946176 | doi = 10.1371/journal.pone.0247969 | bibcode = 2021PLoSO..1647969K | doi-access = free }}
• Articulated postcranial skeleton of an indeterminate ankylosaurid dinosaur is described from the Barun Goyot Formation (Mongolia) by Park et al. (2021), who interpret this specimen as indicating that Asian ankylosaurids evolved rigid bodies with a reduced number of pedal phalanges, as well as the existence of at least two forms of flank armor in ankylosaurids, and discuss possible adaptations for digging in ankylosaurids.{{cite journal | vauthors = Park JY, Lee YN, Currie PJ, Ryan MJ, Bell P, Sissons R, Koppelhus EB, Barsbold R, Lee S, Kim SH | display-authors = 6 | title = A new ankylosaurid skeleton from the Upper Cretaceous Baruungoyot Formation of Mongolia: its implications for ankylosaurid postcranial evolution | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 4101 | date = March 2021 | pmid = 33737515 | pmc = 7973727 | doi = 10.1038/s41598-021-83568-4 }}

• A study on the skeletal anatomy and phylogenetic relationships of Haya griva is published by Barta & Norell (2021).{{cite journal| vauthors = Barta DE, Norell MA |year=2021|title=The osteology of Haya griva (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia|journal=Bulletin of the American Museum of Natural History|volume=445|pages=1–112|doi=10.1206/0003-0090.445.1.1|hdl=2246/7253|s2cid=232059318|url=https://www.biodiversitylibrary.org/item/297109}}
• Duncan et al. (2021) describe ornithopod jaws from the Lower Cretaceous Eumeralla Formation (Australia), and evaluate the implications of these fossils for the knowledge of the diversity of Early Cretaceous ornithopods from this area.{{cite journal| vauthors = Duncan RJ, Evans AR, Vickers-Rich P, Rich TH, Poropat SF |year=2021 |title=Ornithopod jaws from the Lower Cretaceous Eumeralla Formation, Victoria, Australia, and their implications for polar neornithischian dinosaur diversity |journal=Journal of Vertebrate Paleontology |volume=41 |issue=3 |pages=e1946551 |doi=10.1080/02724634.2021.1946551 |bibcode=2021JVPal..41E6551D |s2cid=238672791 |url=https://research.monash.edu/en/publications/1deae4e9-3b35-401d-b608-8d48016cca27 }}
• A study on the anatomy of the manus of Tenontosaurus tilletti is published by Hunt, Cifelli & Davies (2021).{{cite journal| vauthors = Hunt TC, Cifelli RL, Davies KL |title=The hand of Tenontosaurus tilletti (Dinosauria, Ornithopoda) |journal= Journal of Vertebrate Paleontology|year= 2021|volume=41 |issue=2 |pages=e1938591 |doi=10.1080/02724634.2021.1938591 |bibcode=2021JVPal..41E8591H |s2cid=237517997 }}
• A study on the accumulated remains of Dysalotosaurus lettowvorbecki from the Upper Jurassic Tendaguru Formation (Tanzania) is published by Hübner et al. (2021), who interpret two large bonebeds as most likely resulting from two independent catastrophic mortality events.{{cite journal| vauthors = Hübner TR, Foth C, Heinrich WD, Schwarz D, Bussert R |year=2021|title=Research history, taphonomy, and age structure of a mass accumulation of the ornithopod dinosaur Dysalotosaurus lettowvorbecki from the Upper Jurassic of Tanzania|journal=Acta Palaeontologica Polonica|volume=66|issue=2|pages=275–300|doi=10.4202/app.00687.2019|s2cid=236713607|doi-access=free}}
• A study on the anatomy of the braincase and probable brain size in Proa valdearinnoensis is published by Knoll et al. (2021).{{cite journal| vauthors = Knoll F, Lautenschlager S, Kawabe S, Martínez G, Espílez E, Mampel L, Alcalá L |title=Palaeoneurology of the Early Cretaceous iguanodont Proa valdearinnoensis and its bearing on the parallel developments of cognitive abilities in theropod and ornithopod dinosaurs |journal=Journal of Comparative Neurology |year=2021 |volume=529 |issue=18 |pages=3922–3945 |doi=10.1002/cne.25224 |pmid=34333763 |s2cid=236774128 |hdl=10261/250160 |hdl-access=free }}
• A specimen of Gobihadros mongoliensis preserving features of cessation of growth, indicating that it reached the terminal size and advanced age, is described from the Upper Cretaceous Bayan Shireh Formation (Mongolia) by Słowiak et al. (2021), who diagnose this specimen as affected by calcium pyrophosphate deposition disease, making it the first known non-avian dinosaur specimen affected with this disease.{{cite journal| vauthors = Słowiak J, Szczygielski T, Rothschild BM, Surmik D |title=Dinosaur senescence: a hadrosauroid with age-related diseases brings a new perspective of "old" dinosaurs |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 11947 |doi=10.1038/s41598-021-91366-1 |doi-access=free |pmid=34117305 |pmc=8196189 |bibcode=2021NatSR..1111947S }}
• Redescription of the anatomy and a study on the phylogenetic relationships of Lophorhothon atopus, based on data from the holotype and from a new specimen, is published by Gates & Lamb (2021).{{cite journal| vauthors = Gates TA, Lamb J |year=2021|title=Redescription of Lophorhothon atopus (Ornithopoda: Dinosauria) from the Late Cretaceous of Alabama based on new material|journal=Canadian Journal of Earth Sciences|volume=58|issue=9|pages=918–935|doi=10.1139/cjes-2020-0173|bibcode=2021CaJES..58..918G|s2cid=234293555}}
• A study on the anatomy of the postcranial skeleton of Tanius sinensis is published by Borinder et al. (2021).{{cite journal| vauthors = Borinder NH, Poropat SF, Campione NE, Wigren T, Kear BP |title=Postcranial osteology of the basally branching hadrosauroid dinosaur Tanius sinensis from the Upper Cretaceous Wangshi Group of Shandong, China |journal= Journal of Vertebrate Paleontology|year= 2021|volume=41 |issue=1 |pages=e1914642 |doi=10.1080/02724634.2021.1914642 |bibcode=2021JVPal..41E4642B |s2cid=235364845 |doi-access=free }}
• Description of new fossil material of Tethyshadros insularis from the Villaggio del Pescatore fossil site (Italy), a study on the age of this site and on the phylogenetic affinities of T. insularis, and a reevaluation of claims about the evolution of insular dwarfism in Late Cretaceous hadrosauroids, is published by Chiarenza et al. (2021).{{cite journal| vauthors = Chiarenza AA, Fabbri M, Consorti L, Muscioni M, Evans DC, Cantalapiedra JL, Fanti F |title=An Italian dinosaur Lagerstätte reveals the tempo and mode of hadrosauriform body size evolution |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 23295 |doi=10.1038/s41598-021-02490-x |pmid=34857789 |pmc=8640049 |bibcode=2021NatSR..1123295C |doi-access=free }}
• Description of new fossil material of hadrosaurids from the Upper Cretaceous Lago Colhué Huapí Formation (Argentina), and a study on the environment inhabited by these hadrosaurids and on the influence of paleoenvironmental conditions on South American hadrosaurid distribution, is published by Ibiricu et al. (2021).{{cite journal| vauthors = Ibiricu LM, Casal GA, Alvarez BN, De Sosa Tomas A, Lamanna MC, Cruzado-Caballero P |year=2021 |title=New hadrosaurid (Dinosauria: Ornithopoda) fossils from the uppermost Cretaceous of central Patagonia and the influence of paleoenvironment on South American hadrosaur distribution |journal=Journal of South American Earth Sciences |volume=110 |pages=Article 103369 |doi=10.1016/j.jsames.2021.103369 |bibcode=2021JSAES.11003369I }}
• Holland et al. (2021) describe an assemblage of late juvenile hadrosaurid specimens from the Spring Creek Bonebed (Alberta, Canada), representing the first record of lambeosaurines from the Wapiti Formation and possibly indicating that age segregation was a life history strategy among hadrosaurids.{{cite journal| vauthors = Holland B, Bell PR, Fanti F, Hamilton SM, Larson DW, Sissons R, Sullivan C, Vavrek MJ, Wang Y, Campione NE |year=2021 |title=Taphonomy and taxonomy of a juvenile lambeosaurine (Ornithischia: Hadrosauridae) bonebed from the late Campanian Wapiti Formation of northwestern Alberta, Canada |journal=PeerJ |volume=9 |pages=e11290 |doi=10.7717/peerj.11290 |pmid=33987001 |pmc=8103918 |doi-access=free }}
• Revision of the type material and a study on the phylogenetic affinities of Latirhinus uitstlani is published by Ramírez-Velasco, Espinosa-Arrubarrena & Alvarado-Ortega (2021);{{cite journal| vauthors = Ramírez-Velasco ÁA, Espinosa-Arrubarrena L, Alvarado-Ortega J |year=2021 |title=Review of the taxonomic affinities of Latirhinus uitstlani, an emblematic Mexican hadrosaurid |journal=Journal of South American Earth Sciences |volume=110 |pages=Article 103391 |doi=10.1016/j.jsames.2021.103391 |bibcode=2021JSAES.11003391R }} a study on the taphonomy of the skeletal elements in the holotype of L. uitstlani designated by the aforementioned authors, on the skeletal composition of the holotype, on the diagnostic utility of the characters used by Ramírez-Velasco, Espinosa-Arrubarrena & Alvarado-Ortega (2021) for referring other specimens to different hadrosaurid clades, and on the phylogenetic affinities of L. uitstlani is subsequently published by Serrano-Brañas & Prieto-Márquez (2021).{{cite journal| vauthors = Serrano-Brañas CI, Prieto-Márquez A |year=2021 |title=Taphonomic attributes of the holotype of the lambeosaurine dinosaur Latirhinus uitstlani from the late Campanian of Mexico: Implications for its phylogenetic systematic |journal=Journal of South American Earth Sciences |volume=114 |pages=Article 103689 |doi=10.1016/j.jsames.2021.103689 |url=https://ddd.uab.cat/record/271648 }}
• Redescription of Parasaurolophus cyrtocristatus, based on data from a new skull from the Campanian Fruitland Formation (New Mexico, United States), is published by Gates, Evans & Sertich (2021).{{cite journal | vauthors = Gates TA, Evans DC, Sertich JJ | title = Description and rediagnosis of the crested hadrosaurid (Ornithopoda) dinosaur Parasaurolophus cyrtocristatus on the basis of new cranial remains | journal = PeerJ | volume = 9 | pages = e10669 | year = 2021 | pmid = 33552721 | pmc = 7842145 | doi = 10.7717/peerj.10669 | doi-access = free }}
• A study on the injuries of the holotype specimen of Bonapartesaurus rionegrensis, and on their implications for the knowledge of its paleobiology, is published by Cruzado-Caballero et al. (2021).{{cite journal| vauthors = Cruzado-Caballero P, Lecuona A, Cerda I, Díaz-Martínez I |title=Osseous paleopathologies of Bonapartesaurus rionegrensis (Ornithopoda, Hadrosauridae) from Allen Formation (Upper Cretaceous) of Patagonia Argentina |journal=Cretaceous Research |year=2021 |volume=124 |pages=Article 104800 |doi=10.1016/j.cretres.2021.104800 |bibcode=2021CrRes.12404800C |hdl=11336/183883 |s2cid=233648171 |hdl-access=free }}
• Five new partial skulls of Maiasaura peeblesorum, providing information on the acquisition of the crest and changes to the surrounding cranial elements during the ontogeny of this dinosaur, are described from the Campanian Two Medicine Formation (Montana, United States) by McFeeters, Evans & Maddin (2021).{{cite journal | vauthors = McFeeters B, Evans DC, Maddin HV | title = Ontogeny and variation in the skull roof and braincase of the hadrosaurid dinosaur Maiasaura peeblesorum from the Upper Cretaceous of Montana, USA | journal = Acta Palaeontologica Polonica | volume = 66 | issue = 3 | pages = 485–507 | year = 2021 | doi = 10.4202/app.00698.2019 | s2cid = 239729209 | doi-access = free }}
• A study aiming to determine the taxonomic validity of the species Sphaerotholus buchholtzae and S. edmontonensis is published by Woodruff et al. (2021).{{cite journal| vauthors = Woodruff DC, Goodwin MB, Lyson TR, Evans DC |year=2021 |title=Ontogeny and variation of the pachycephalosaurine dinosaur Sphaerotholus buchholtzae, and its systematics within the genus |journal=Zoological Journal of the Linnean Society |volume=193 |issue=2 |pages=563–601 |doi=10.1093/zoolinnean/zlaa179 }}
• Vinther, Nicholls & Kelly (2021) describe the first fossil cloacal vent in an exceptionally preserved non-avian dinosaur specimen (a specimen of Psittacosaurus from the Early Cretaceous Jehol deposits of Liaoning, China).{{cite journal | vauthors = Vinther J, Nicholls R, Kelly DA | title = A cloacal opening in a non-avian dinosaur | journal = Current Biology | volume = 31 | issue = 4 | pages = R182–R183 | date = February 2021 | pmid = 33472049 | doi = 10.1016/j.cub.2020.12.039 | s2cid = 231644183 | doi-access = free | bibcode = 2021CBio...31.R182V }}
• A study on jaws and teeth of juvenile and adult specimens of Psittacosaurus lujiatunensis, aiming to determine whether this dinosaur underwent a dietary shift during its ontogeny, is published by Landi et al. (2021).{{cite journal| vauthors = Landi D, King L, Zhao Q, Rayfield EJ, Benton MJ |year=2021 |title=Testing for a dietary shift in the Early Cretaceous ceratopsian dinosaur Psittacosaurus lujiatunensis |journal=Palaeontology |volume=64 |issue=3 |pages=371–384 |doi=10.1111/pala.12529 |bibcode=2021Palgy..64..371L |hdl=1983/9f959247-1bb0-496c-9bed-a5bc306b3746 |s2cid=233689632 |url=https://research-information.bris.ac.uk/ws/files/275823604/pala.12529.pdf }}
• A study on the ontogenetic changes in the femoral histology of Psittacosaurus sibiricus is published by Skutschas et al. (2021).{{cite journal | vauthors = Skutschas PP, Morozov SS, Averianov AO, Leshchinskiy SV, Ivantsov SV, Fayngerts AV, Feofanova OA, Vladimirova ON, Slobodin DA | title = Femoral histology and growth patterns of the ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of Western Siberia | journal = Acta Palaeontologica Polonica | volume = 66 |issue=2 |pages=437–447 | year = 2021 | doi = 10.4202/app.00819.2020 | s2cid = 237336322 |url=https://www.app.pan.pl/archive/published/app66/app008192020.pdf }}
• A study on the whole-skull shape in a large sample of specimens of Protoceratops andrewsi is published by Knapp, Knell & Hone (2021), who argue that the frill of P. andrewsi shows several characteristics consistent with a socio-sexual trait.{{cite journal | vauthors = Knapp A, Knell RJ, Hone DW | title = Three-dimensional geometric morphometric analysis of the skull of Protoceratops andrewsi supports a socio-sexual signalling role for the ceratopsian frill | journal = Proceedings. Biological Sciences | volume = 288 | issue = 1944 | pages = 20202938 | date = February 2021 | pmid = 33529562 | pmc = 7893235 | doi = 10.1098/rspb.2020.2938 }}
• A study on the anatomy of a specimen of Protoceratops andrewsi from the Bayan Zag locality (Djadochta Formation, Mongolia), interpreted as most likely to be a large immature female, and on its implications for explanation of the polymorphism in the fossil material attributed to P. andrewsi and for diagnosing P. andrewsi from vertebrae considering the age and sex of compared specimens, is published by Tereshchenko (2021).{{cite journal| author = Tereshchenko VS |year=2021 |title=Axial Skeleton of Subadult Protoceratops andrewsi from Djadokhta Formation (Upper Cretaceous, Mongolia) |journal=Paleontological Journal |volume=55 |issue=12 |pages=1408–1457 |doi=10.1134/S0031030121120030 |bibcode=2021PalJ...55.1408T |s2cid=247387644 }}
• Description of a skull of a subadult specimen of Einiosaurus procurvicornis from the Two Medicine Formation (Montana, United States), and a study on the implications of this specimen for the knowledge of the sequence and timing of development of primary cranial ornaments in eucentrosauran ceratopsids, is published by Wilson & Scannella (2021).{{cite journal | vauthors = Wilson JP, Scannella JB | title = Comparative cranial osteology of subadult eucentrosauran ceratopsid dinosaurs from the Two Medicine Formation, Montana, indicates sequence of ornamentation development and complex supraorbital ontogenetic change | journal = Acta Palaeontologica Polonica | volume = 66 | issue = 4 | pages = 797–814 | year = 2021 | doi = 10.4202/app.00797.2020 | s2cid = 245247322 | doi-access = free }}
• A study on the dentition of Stegoceras validum and Thescelosaurus neglectus, and on its implications for the knowledge of the feeding behavior of these ornithischians, is published by Hudgins, Currie & Sullivan (2021).{{cite journal | vauthors = Hudgins MN, Currie PJ, Sullivan C | title = Dental assessment of Stegoceras validum (Ornithischia: Pachycephalosauridae) and Thescelosaurus neglectus (Ornithischia: Thescelosauridae): paleoecological inferences | journal = Cretaceous Research | volume = 130 | pages = Article 105058 | year = 2021 | doi = 10.1016/j.cretres.2021.105058| issn=0195-6671 | s2cid = 239253658 | url = https://www.sciencedirect.com/science/article/abs/pii/S0195667121003062 | url-access = subscription }}
• A study on the biodiversity patterns of Late Cretaceous hadrosaurids and ceratopsids from the western interior of North America, evaluating whether the fossil record provides evidence of faunal provinciality of these dinosaurs, is published by Maidment et al. (2021).{{cite journal| vauthors = Maidment SC, Dean CD, Mansergh RI, Butler RJ |year=2021 |title=Deep-time biodiversity patterns and the dinosaurian fossil record of the Late Cretaceous Western Interior, North America |journal=Proceedings of the Royal Society B: Biological Sciences |volume=288 |issue=1953 |pages=Article ID 20210692 |doi=10.1098/rspb.2021.0692 |pmid=34157868 |pmc=8220268 }}

• The study on the phylogenetic relationships and powered flight potential of early birds and their closest relatives published by Pei et al. (2020), arguing that the potential for powered flight evolved at least three times (once in birds and twice in dromaeosaurids),{{cite journal|display-authors=6|vauthors=Pei R, Pittman M, Goloboff PA, Dececchi TA, Habib MB, Kaye TG, Larsson HC, Norell MA, Brusatte SL, Xu X|date=October 2020|title=Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds|journal=Current Biology|volume=30|issue=20|pages=4033–4046.e8|doi=10.1016/j.cub.2020.06.105|pmid=32763170|s2cid=221015472|doi-access=free|bibcode=2020CBio...30E4033P |hdl=11336/143103|hdl-access=free}} is criticized by Serrano & Chiappe (2021).{{cite journal|vauthors=Serrano FJ, Chiappe LM|year=2021|title=Independent origins of powered flight in paravian dinosaurs?|journal=Current Biology|volume=31|issue=8|pages=R370–R372|doi=10.1016/j.cub.2021.03.058|pmid=33905689|s2cid=233428158|doi-access=free|bibcode=2021CBio...31.R370S |hdl=10630/32667|hdl-access=free}}{{cite journal|display-authors=6|vauthors=Pittman M, Habib MB, Dececchi TA, Larsson HC, Pei R, Kaye TG, Norell MA, Brusatte SL, Xu X|year=2021|title=Response to Serrano and Chiappe|journal=Current Biology|volume=31|issue=8|pages=R372–R373|doi=10.1016/j.cub.2021.03.059|pmid=33905690|s2cid=233429338|doi-access=free|bibcode=2021CBio...31.R372P }}
• Review of the most relevant events in limb evolution across the dinosaur-bird transition and the origins of bird flight is published by Nebreda, Hernández Fernández & Marugán-Lobón (2021).{{cite journal|vauthors=Nebreda SM, Hernández Fernández M, Marugán-Lobón J|year=2021|title='Dinosaur-bird' macroevolution, locomotor modules and the origins of flight|journal=Journal of Iberian Geology|volume=47|issue=3|pages=565–574|doi=10.1007/s41513-021-00170-3|issn=1698-6180 |doi-access=free|bibcode=2021JIbG...47..565N |hdl=10486/700623|hdl-access=free}}
• A study on the diversification rates of birds throughout their evolutionary history is published by Yu, Zhang & Xu (2021).{{cite journal|vauthors=Yu Y, Zhang C, Xu X|date=March 2021|title=Deep time diversity and the early radiations of birds|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=118|issue=10|pages=e2019865118|doi=10.1073/pnas.2019865118|pmc=7958206|pmid=33619176|bibcode=2021PNAS..11819865Y |doi-access=free }}
• A study on the evolution of the brain in birds, based on data from extant and recently extinct birds, Archaeopteryx and non-avian coelurosaurian theropods, is published by Watanabe et al. (2021).{{cite journal|vauthors=Watanabe A, Balanoff AM, Gignac PM, Gold ME, Norell MA|year=2021|title=Novel neuroanatomical integration and scaling define avian brain shape evolution and development|journal=eLife|volume=10|pages=e68809|doi=10.7554/eLife.68809|pmc=8260227|pmid=34227464 |doi-access=free }}
• A study aiming to infer the diets of the last common ancestor of living birds, based on data from digestive system-related genes, is published by Wu (2021), who interprets his findings as indicative of a diet shift from carnivory to herbivory at the non-avian archosaur-to-bird transition, and evaluates possible implications of this diet shift for the evolution of early birds.{{cite journal|vauthors=Wu Y|year=2021|title=Molecular phyloecology suggests a trophic shift concurrent with the evolution of the first birds|journal=Communications Biology|volume=4|issue=1|pages=Article number 547|doi=10.1038/s42003-021-02067-4|pmc=8119460|pmid=33986452}}
• Review of methods used to determine diet in modern and fossil birds, evaluating their utility for determination of diets of Mesozoic birds, is published by Miller & Pittman (2021).{{cite journal|vauthors=Miller CV, Pittman M|year=2021|title=The diet of early birds based on modern and fossil evidence and a new framework for its reconstruction|journal=Biological Reviews|volume=96|issue=5|pages=2058–2112|doi=10.1111/brv.12743|pmc=8519158|pmid=34240530|s2cid=235775809}}
• A study on patterns and modes of the evolution of skeletal morphology and limb proportions in Mesozoic birds is published by Wang et al. (2021).{{cite journal|vauthors=Wang M, Lloyd GT, Zhang C, Zhou Z|date=February 2021|title=The patterns and modes of the evolution of disparity in Mesozoic birds|journal=Proceedings. Biological Sciences|volume=288|issue=1944|pages=20203105|doi=10.1098/rspb.2020.3105|pmc=7893231|pmid=33529566}}
• A study on the variation in tooth crown shape of Mesozoic birds, and its implications for the knowledge of their diets, is published by Zhou et al. (2021).{{cite journal|vauthors=Zhou YC, Sullivan C, Zhou ZH, Zhang FC|year=2021|title=Evolution of tooth crown shape in Mesozoic birds, and its adaptive significance with respect to diet|journal=Palaeoworld|volume=30|issue=4|pages=724–736|doi=10.1016/j.palwor.2020.12.008|s2cid=234117375}}
• A study on the impact of tooth loss on the diversification of Mesozoic birds is published by Brocklehurst & Field (2021), who find no evidence for a link between toothlessness and accelerated cladogenesis, as well as no evidence for models whereby acquisitions of toothlessness among Mesozoic birds were driven by an overarching selective trend.{{cite journal|vauthors=Brocklehurst N, Field DJ|date=March 2021|title=Macroevolutionary dynamics of dentition in Mesozoic birds reveal no long-term selection towards tooth loss|journal=iScience|volume=24|issue=3|pages=102243|bibcode=2021iSci...24j2243B|doi=10.1016/j.isci.2021.102243|pmc=7973866|pmid=33763634}}
• Review of the variability of bone histology in basal members of Avialae is published by Monfroy & Kundrát (2021).{{cite journal|vauthors=Monfroy QT, Kundrát M|year=2021|title=The osteohistological variability in the evolution of basal avialans|journal=Acta Zoologica|volume=103|issue=1|pages=1–28|doi=10.1111/azo.12396|s2cid=237806144}}
• A study on the ecomorphology of extant and fossil birds, aiming to determine whether the ecologies of Mesozoic birds can be inferred on the basis of data from measurements of their forelimbs and hindlimbs, is published by Bell et al. (2021).{{cite journal|vauthors=Bell A, Marugán-Lobón J, Navalón G, Nebreda SM, DiGuildo J, Chiappe LM|year=2021|title=Quantitative Analysis of Morphometric Data of Pre-modern Birds: Phylogenetic Versus Ecological Signal|journal=Frontiers in Earth Science|volume=9|pages=Article 663342|bibcode=2021FrEaS...9..534B|doi=10.3389/feart.2021.663342|doi-access=free|hdl=10486/705668|hdl-access=free}}
• The study published by Kaye, Pittman & Wahl (2020), reporting evidence interpreted by the authors as indicative of the feather moulting in the Thermopolis specimen of Archaeopteryx,{{Cite journal|vauthors=Kaye TG, Pittman M, Wahl WR|year=2020|title=Archaeopteryx feather sheaths reveal sequential center-out flight-related molting strategy|journal=Communications Biology|volume=3|issue=1|pages=Article number 745|doi=10.1038/s42003-020-01467-2|pmc=7722847|pmid=33293660}} is criticized by Kiat et al. (2021).{{Cite journal|vauthors=Kiat Y, Pyle P, Balaban A, O'Connor JK|year=2021|title=Reinterpretation of purported molting evidence in the Thermopolis Archaeopteryx|journal=Communications Biology|volume=4|issue=1|pages=Article number 837|doi=10.1038/s42003-021-02349-x|pmc=8257594|pmid=34226661|s2cid=235738230}}{{Cite journal|vauthors=Kaye TG, Pittman M|year=2021|title=Reply to: Reinterpretation of purported molting evidence in the Thermopolis Archaeopteryx|journal=Communications Biology|volume=4|issue=1|pages=Article number 839|doi=10.1038/s42003-021-02367-9|pmc=8257677|pmid=34226634|s2cid=235738222}}
• A study on the cellular preservation in the calcified cartilage of specimens of Confuciusornis and Yanornis from the Early Cretaceous Jehol biota (northeast China) is published by Bailleul & Zhou (2021).{{cite journal|vauthors=Bailleul AM, Zhou Z|year=2021|title=SEM Analyses of Fossilized Chondrocytes in the Extinct Birds Yanornis and Confuciusornis: Insights on Taphonomy and Modes of Preservation in the Jehol Biota|journal=Frontiers in Earth Science|volume=9|pages=Article 718588|bibcode=2021FrEaS...9..694B|doi=10.3389/feart.2021.718588|doi-access=free}}
• A study on the nanostructures of the melanosomes sampled from a specimen of Eoconfuciusornis from the Lower Cretaceous Huajiying Formation (China) is published by Pan et al. (2021), who interpret their findings as evidence of brilliant iridescent plumage color in Eoconfuciusornis.{{cite journal|vauthors=Pan Y, Li Z, Wang M, Zhao T, Wang X, Zheng X|year=2021|title=Unambiguous evidence of brilliant iridescent feather color from hollow melanosomes in an Early Cretaceous bird|journal=National Science Review|volume=9|issue=2|pages=nwab227|doi=10.1093/nsr/nwab227|pmid=35145706|pmc=8824705}}
• A study on the histology of the scapulocoracoid in Confuciusornis is published by Wu et al. (2021).{{cite journal|vauthors=Wu Q, Bailleul AM, Li Z, O'Connor JK, Zhou Z|year=2021|title=Osteohistology of the Scapulocoracoid of Confuciusornis and Preliminary Analysis of the Shoulder Joint in Aves|journal=Frontiers in Earth Science|volume=9|pages=Article 617124|bibcode=2021FrEaS...9..252W|doi=10.3389/feart.2021.617124|doi-access=free|s2cid=233216074}}
• New enantiornithine specimen with a well-preserved skull, retaining the plesiomorphic dinosaurian palate and diapsid temporal configurations indicative of an akinetic skull, is described from the Lower Cretaceous Jiufotang Formation (China) by Wang et al. (2021), who evaluate the implications of this specimen for the knowledge of the evolution of bird skulls.{{cite journal|vauthors=Wang M, Stidham TA, Li Z, Xu X, Zhou Z|year=2021|title=Cretaceous bird with dinosaur skull sheds light on avian cranial evolution|journal=Nature Communications|volume=12|issue=1|pages=Article number 3890|bibcode=2021NatCo..12.3890W|doi=10.1038/s41467-021-24147-z|pmc=8222284|pmid=34162868}}
• A study on teeth replacement patterns in members of Enantiornithes, based on data from three specimens from the Cretaceous Adamantina Formation (Brazil), is published by Wu et al. (2021).{{cite journal|vauthors=Wu YH, Chiappe LM, Bottjer DJ, Nava W, Martinelli AG|year=2021|title=Dental replacement in Mesozoic birds: evidence from newly discovered Brazilian enantiornithines|journal=Scientific Reports|volume=11|issue=1|pages=Article number 19349|doi=10.1038/s41598-021-98335-8|pmc=8484441|pmid=34593843|bibcode=2021NatSR..1119349W|doi-access=free}}
• A study aiming to infer resting metabolic rates of Concornis and Iberomesornis on the basis of data from bone histology is published by Cubo et al. (2021).{{cite journal|vauthors=Cubo J, Buscalioni AD, Legendre LJ, Bourdon E, Sanz JL, de Ricqlès A|year=2021|title=Palaeohistological inferences of resting metabolic rates in Concornis and Iberomesornis (Enantiornithes, Ornithothoraces) from the Lower Cretaceous of Las Hoyas (Spain)|journal=Palaeontology|volume=65|doi=10.1111/pala.12583|s2cid=245082389}}
• A study on the anatomy of the quadrate bone of Longipteryx chaoyangensis, evaluating its possible functional implications, is published by Stidham & O'Connor (2021), who consider Camptodontornis yangi and Shengjingornis yangi as synonyms of Longipteryx.{{cite journal|vauthors=Stidham TA, O'Connor JK|year=2021|title=The evolutionary and functional implications of the unusual quadrate of Longipteryx chaoyangensis (Avialae: Enantiornithes) from the Cretaceous Jehol Biota of China|journal=Journal of Anatomy|volume=239|issue=5|pages=1066–1074|doi=10.1111/joa.13487|pmid=34137030|pmc=8546525|s2cid=235462145}}
• Description of a new bohaiornithid specimen from the Lower Cretaceous Jiufotang Formation (China), providing new information on the skull anatomy and teeth replacement pattern in bohaiornithids, and a study on the phylogenetic relationships of enantiornithines traditionally included in the family Bohaiornithidae, is published by Liu et al. (2021; final version published in 2022).{{cite journal|vauthors=Liu D, Chiappe LM, Wu B, Meng Q, Zhang Y, Qiu R, Xing H, Zeng Z|year=2022|title=Cranial and dental morphology in a bohaiornithid enantiornithine with information on its tooth replacement pattern|journal=Cretaceous Research|volume=129|pages=Article 105021|doi=10.1016/j.cretres.2021.105021|bibcode=2022CrRes.12905021L |s2cid=239630226}}
• A study on the identity of purported gastroliths reported in a referred specimen of Bohaiornis guoi from the Early Cretaceous of China is published by Liu et al. (2021).{{cite journal|vauthors=Liu S, Li Z, Bailleul AM, Wang M, O'Connor J|year=2021|title=Investigating Possible Gastroliths in a Referred Specimen of Bohaiornis guoi (Aves: Enantiornithes)|journal=Frontiers in Earth Science|volume=9|pages=Article 635727|bibcode=2021FrEaS...9...62L|doi=10.3389/feart.2021.635727|doi-access=free|s2cid=231956411}}
• A study on the bone histology and growth of the skeleton of Mirarce eatoni is published by Atterholt et al. (2021).{{cite journal|vauthors=Atterholt J, Poust AW, Erickson GM, O'Connor JK|year=2021|title=Intraskeletal Osteohistovariability Reveals Complex Growth Strategies in a Late Cretaceous Enantiornithine|journal=Frontiers in Earth Science|volume=9|pages=Article 640220|bibcode=2021FrEaS...9..118A|doi=10.3389/feart.2021.640220|doi-access=free|s2cid=232313411}}
• An almost complete juvenile specimen of Archaeorhynchus is described from the Aptian Jiufotang Formation (China) by Foth et al. (2021), who evaluate the implications of the anatomy of this specimen for the knowledge of the ontogenetic development of Mesozoic birds.{{cite journal|vauthors=Foth C, Wang S, Spindler F, Lin Y, Rui Y|year=2021|title=A Juvenile Specimen of Archaeorhynchus Sheds New Light on the Ontogeny of Basal Euornithines|journal=Frontiers in Earth Science|volume=9|pages=Article 604520|bibcode=2021FrEaS...9..149F|doi=10.3389/feart.2021.604520|doi-access=free|s2cid=233245857}}
• A study on variations in bone growth and on the thermal regime of Yanornis martini is published by Monfroy et al. (2021).{{cite journal|vauthors=Monfroy QT, Kundrát M, Uesugi K, Hoshino M|year=2021|title=Dichotomy in formation and growth of bones of Yanornis martini (Pygostylia, Ornithuromorpha): study of thermal regime in an extinct bird|journal=Historical Biology|volume=34|issue=6 |pages=1039–1062|doi=10.1080/08912963.2021.1960323|s2cid=238739475}}
• Ju et al. (2021) revise the fossil material of Iteravis huchzermeyeri and Gansus zheni, and consider these species to be synonymous.{{cite journal|vauthors=Ju S, Wang X, Liu Y, Wang Y|year=2021|title=A reassessment of Iteravis huchzermeyeri and Gansus zheni from the Jehol Biota in western Liaoning, China|journal=China Geology|volume=4|issue=2|pages=197–204|doi=10.31035/cg2020066|bibcode=2021CGeo....4..197J |s2cid=234992401|doi-access=free}}
• A study on the bone histology of Gansus yumenensis, and on its implications for the knowledge of the evolution of uninterrupted bone deposition in birds, is published by Monfroy et al. (2021).{{cite journal|vauthors=Monfroy QT, Kundrát M, O'Connor JK, You HL, Marone F, Stampanoni M, Šmajda B|title=Synchrotron microtomography-based osteohistology of Gansus yumenensis: new data on the evolution of uninterrupted bone deposition in basal birds|journal=Acta Zoologica|year=2023 |volume=104 |issue=2 |pages=149–175 |doi=10.1111/azo.12402|s2cid=238322919}}
• A cervical vertebra of a member of Ornithuromorpha distinct from Gargantuavis, representing the first fossil evidence of a giant bird from the late Maastrichtian of Europe reported to date, is described from Beranuy (Huesca, Spain) by Pérez-Pueyo et al. (2021).{{cite journal|vauthors=Pérez-Pueyo M, Cruzado-Caballero P, Moreno-Azanza M, Vila B, Castanera D, Gasca JM, Puértolas-Pascual E, Bádenas B, Canudo JI|year=2021|title=First record of a giant bird (Ornithuromorpha) from the uppermost Maastrichtian of the Southern Pyrenees, northeast Spain|journal=Journal of Vertebrate Paleontology|volume=41|issue=1|pages=e1900210|doi=10.1080/02724634.2021.1900210|bibcode=2021JVPal..41E0210P |s2cid=235506488}}
• Torres, Norell & Clarke (2021) describe a new specimen of Ichthyornis dispar from the Niobrara Formation (Kansas, United States), preserving a nearly complete skull, and evaluate the implications of the anatomy of this specimen for the knowledge of the evolution of birds and for the knowledge of probable reasons why birds survived the end-Cretaceous mass extinction.{{cite journal|vauthors=Torres CR, Norell MA, Clarke JA|year=2021|title=Bird neurocranial and body mass evolution across the end-Cretaceous mass extinction: The avian brain shape left other dinosaurs behind|journal=Science Advances|volume=7|issue=31|pages=eabg7099|bibcode=2021SciA....7.7099T|doi=10.1126/sciadv.abg7099|pmc=8324052|pmid=34330706|doi-access=free}}
• New information on the anatomy of Vegavis iaai, based on data from the holotype specimen which was fully extracted from the sedimentary matrix, is presented by Acosta Hospitaleche & Worthy (2021).{{cite journal|vauthors=Acosta Hospitaleche C, Worthy TH|year=2021|title=New data on the Vegavis iaai holotype from the Maastrichtian of Antarctica|journal=Cretaceous Research|volume=124|pages=Article 104818|doi=10.1016/j.cretres.2021.104818|bibcode=2021CrRes.12404818A |s2cid=233703816}}
• Mayr & Zelenkov (2021) interpret eogruids and ergilornithids as representatives of the stem group of Struthioniformes, based on data from new fossils from the late Eocene of Mongolia.{{cite journal|vauthors=Mayr G, Zelenkov N|year=2021|title=Extinct crane-like birds (Eogruidae and Ergilornithidae) from the Cenozoic of Central Asia are indeed ostrich precursors|journal=Ornithology|volume=138|issue=4|pages=ukab048|doi=10.1093/ornithology/ukab048|doi-access=free}}
• A fossil ostrich specimen with exceptional soft-tissue preservation is described from the Miocene Liushu Formation (Linxia Basin, China) by Li et al. (2021).{{cite journal|vauthors=Li ZH, Bailleul AM, Stidham TA, Wang M, Deng T|year=2021|title=Exceptional preservation of an extinct ostrich from the Late Miocene Linxia Basin of China|journal=Vertebrata PalAsiatica|volume=59|issue=3|pages=229–244|doi=10.19615/j.cnki.1000-3118.210309}}
• A femur of a giant ostrich, significantly larger than the living common ostrich, is described from the Pleistocene Nihewan Formation (China) by Buffetaut & Angst (2021), who assign it to Pachystruthio indet. and interpret this finding as evidence of wide geographical distribution of giant ostriches in the Early Pleistocene of Eurasia.{{cite journal|vauthors=Buffetaut E, Angst D|year=2021|title=A giant ostrich from the Lower Pleistocene Nihewan Formation of North China, with a review of the fossil ostriches of China|journal=Diversity|volume=13|issue=2|pages=Article 47|doi=10.3390/d13020047|doi-access=free|bibcode=2021Diver..13...47B |hdl=1983/0d3c1bba-d496-47b6-a61c-e141a472612a|hdl-access=free}}
• A study on the phylogenetic relationships and evolutionary history of extant and fossil tinamous is published by Almeida et al. (2021).{{cite journal|vauthors=Almeida FC, Porzecanski AL, Cracraft JL, Bertelli S|year=2021|title=The evolution of tinamous (Palaeognathae: Tinamidae) in light of molecular and combined analyses|url=https://academic.oup.com/zoolinnean/advance-article/doi/10.1093/zoolinnean/zlab080/6395171|journal=Zoological Journal of the Linnean Society|volume=195|pages=106–124 |doi=10.1093/zoolinnean/zlab080|url-access=subscription}}
• A mid-Holocene coprolite deposit attributed to the bush moa is reported from southern New Zealand by Wood et al. (2021), who evaluate the implications of this finding for the knowledge of the diet and ecology of this moa.{{cite journal|vauthors=Wood JR, Vermeulen MJ, Bolstridge N, Briden S, Cole TL, Rivera-Perez J, Shepherd LD, Rawlence NJ, Wilmshurst JM|year=2021|title=Mid-Holocene coprolites from southern New Zealand provide new insights into the diet and ecology of the extinct little bush moa (Anomalopteryx didiformis)|journal=Quaternary Science Reviews|volume=263|pages=Article 106992|bibcode=2021QSRv..26306992W|doi=10.1016/j.quascirev.2021.106992|s2cid=236227836}}
• A study comparing egg size and volume in extinct island emus and in mainland emu, aiming to determine egg size in relation to body size in island emus and their breeding strategy, is published by Hume & Robertson (2021).{{cite journal|vauthors=Hume JP, Robertson C|year=2021|title=Eggs of extinct dwarf island emus retained large size|journal=Biology Letters|volume=17|issue=5|pages=Article ID 20210012|doi=10.1098/rsbl.2021.0012|pmc=8150009|pmid=34034528}}
• A study on the phylogenetic relationships of Brontornis burmeisteri is published by Agnolin (2021), who interprets this taxon as a member of Galloanserae.{{cite journal|vauthors=Agnolin FL|year=2021|title=Reappraisal on the Phylogenetic Relationships of the Enigmatic Flightless Bird (Brontornis burmeisteri) Moreno and Mercerat, 1891|journal=Diversity|volume=13|issue=2|pages=Article 90|doi=10.3390/d13020090|doi-access=free|bibcode=2021Diver..13...90A }}
• Reexamination of specimens of Omorhamphus storchii and Gastornis parisiensis alleged to preserve alveoli for teeth is published by Louchart et al. (2021), who reject claims of presence of teeth in gastornithids.{{cite journal|vauthors=Louchart A, Bhullar BA, Riamon S, Field DJ|year=2021|title=The True Identity of Putative Tooth Alveoli in a Cenozoic Crown Bird, the Gastornithid Omorhamphus|journal=Frontiers in Earth Science|volume=9|pages=Article 661699|bibcode=2021FrEaS...9..333L|doi=10.3389/feart.2021.661699|doi-access=free|s2cid=234487888}}
• A study on the morphology of the dromornithid brain, based on data from dromornithid endocast material spanning from the late Oligocene to the late Miocene, is published by Handley & Worthy (2021).{{cite journal|vauthors=Handley WD, Worthy TH|year=2021|title=Endocranial Anatomy of the Giant Extinct Australian Mihirung Birds (Aves, Dromornithidae)|journal=Diversity|volume=13|issue=3|pages=Article 124|doi=10.3390/d13030124|doi-access=free|bibcode=2021Diver..13..124H }}
• A study on the bone histology, growth dynamics and life history of Genyornis newtoni is published by Chinsamy & Worthy (2021).{{cite journal|vauthors=Chinsamy A, Worthy TH|year=2021|title=Histovariability and Palaeobiological Implications of the Bone Histology of the Dromornithid, Genyornis newtoni|journal=Diversity|volume=13|issue=5|pages=Article 219|doi=10.3390/d13050219|doi-access=free|bibcode=2021Diver..13..219C |hdl=11427/35239|hdl-access=free}}
• A study on bone pathologies in specimens of Genyornis newtoni from the Lake Callabonna fossil deposit (Australia) is published by McInerney et al. (2021), who interpret the studied specimens as likely affected by osteomyelitis.{{cite journal|vauthors=McInerney PL, Arnold LJ, Burke C, Camens AB, Worthy TH|year=2021|title=Multiple occurrences of pathologies suggesting a common and severe bone infection in a population of the Australian Pleistocene giant, Genyornis newtoni (Aves, Dromornithidae)|journal=Papers in Palaeontology|volume=8|doi=10.1002/spp2.1415|s2cid=245257837}}
• Partial humerus of a coscoroba swan is described from the Upper Pleistocene Capellanía Formation (Argentina) by Vezzosi et al. (2021), who evaluate the implications of this finding for the knowledge of the knowledge of the dispersal of Neotropical swans during the Pleistocene.{{cite journal|vauthors=Vezzosi RI, Jones W, Gaudioso PJ, Barquez RM|year=2021|title=A Patagonian swan (Anatidae: Anserinae) from the Upper Pleistocene of Austral Chaco (Argentina)|journal=Revista Brasileira de Paleontologia|volume=24|issue=4|pages=369–379|doi=10.4072/rbp.2021.4.07|s2cid=247098582|url=https://sbpbrasil.org/publications/index.php/rbp/article/view/222|doi-access=free}}
• Partial skull of a pheasant-sized galliform land bird of uncertain phylogenetic placement is described from the latest Eocene or earliest Oligocene Jansen Creek Member of the Makah Formation (Washington, United States) by Mayr, Goedert & Rabenstein (2021), who report that this specimen preserves a foramen in the temporal region that enabled the vena profunda to enter the braincase, and interpret this foramen as a previously unnoticed cranial autapomorphy of galliforms.{{cite journal|vauthors=Mayr G, Goedert JL, Rabenstein R|year=2021|title=Cranium of an Eocene/Oligocene pheasant-sized galliform bird from western North America, with the description of a vascular autapomorphy of the Galliformes|journal=Journal of Ornithology|volume=163|pages=315–326|doi=10.1007/s10336-021-01935-4|doi-access=free}}
• Redescription of Columba congi is published by Shen, Stidham & Li (2021).{{cite journal|vauthors=Shen W, Stidham TA, Li ZH|year=2021|title=Reexamination of the oldest pigeon (Aves: Columbidae) from Asia: Columba congi from the Early Pleistocene of Zhoukoudian, Beijing, China|journal=Vertebrata PalAsiatica|volume=59|issue=3|pages=245–256|doi=10.19615/j.cnki.1000-3118.210304}}
• Description of new fossil material of Scandiavis mikkelseni from the Eocene Fur Formation (Denmark), providing new information on the brain anatomy of this bird, and a study on the phylogenetic affinities of Scandiavis is published by Heingård et al. (2021).{{cite journal|vauthors=Heingård M, Musser G, Hall SA, Clarke JA|year=2021|title=New Remains of Scandiavis mikkelseni Inform Avian Phylogenetic Relationships and Brain Evolution|journal=Diversity|volume=13|issue=12|pages=Article 651|doi=10.3390/d13120651|doi-access=free|bibcode=2021Diver..13..651H }}
• Oswald et al. (2021) recover a nearly complete mitochondrial genome of the Haitian cave rail (Nesotrochis steganinos) from fossils, and find this bird to be a relative of the families Sarothruridae and Aptornithidae rather than a rallid as previously thought.{{cite journal|vauthors=Oswald JA, Terrill RS, Stucky BJ, LeFebvre MJ, Steadman DW, Guralnick RP, Allen JM|date=March 2021|title=Ancient DNA from the extinct Haitian cave-rail (Nesotrochis steganinos) suggests a biogeographic connection between the Caribbean and Old World|journal=Biology Letters|volume=17|issue=3|pages=20200760|doi=10.1098/rsbl.2020.0760|pmc=8086980|pmid=33726563|s2cid=232245569}}
• A study reconstructing the wing musculature of the great auk and Mancalla is published by Watanabe, Field & Matsuoka (2021).{{cite journal |last1=Watanabe |first1=Junya |last2=Field |first2=Daniel J. |last3=Matsuoka |first3=Hiroshige |title=Wing Musculature Reconstruction in Extinct Flightless Auks (Pinguinus and Mancalla) Reveals Incomplete Convergence with Penguins (Spheniscidae) Due to Differing Ancestral States |journal=Integrative Organismal Biology |date=2021 |volume=3 |issue=1 |pages=obaa040 |doi=10.1093/iob/obaa040|pmid=34258512 |pmc=8271220 }}
• New fossil material of plotopterids, resembling bones of Olympidytes (which was previously considered endemic to North America), is described from the Eocene to Oligocene Itanoura and Kakinoura formations (Japan) by Mori & Miyata (2021), who interpret these fossils as indicating that early diversity of this family in Japan was higher than previously thought.{{cite journal|vauthors=Mori H, Miyata K|year=2021|title=Early Plotopteridae Specimens (Aves) from the Itanoura and Kakinoura Formations (Latest Eocene to Early Oligocene), Saikai, Nagasaki Prefecture, Western Japan|journal=Paleontological Research|volume=25|issue=2|pages=145–159|doi=10.2517/2020PR018 |issn=1342-8144|s2cid=233029559}}
• New fossil material of plotopterids is described from Washington by Mayr & Goedert (2021), who also revise the species Tonsala buchanani and transfer it to the genus Klallamornis.{{cite journal|vauthors=Mayr G, Goedert JL|year=2021|title=New late Eocene and Oligocene plotopterid fossils from Washington State (USA), with a revision of "Tonsala" buchanani (Aves, Plotopteridae)|journal=Journal of Paleontology|volume=96|pages=224–236|doi=10.1017/jpa.2021.81|s2cid=240582610}}
• A carpometacarpus of a petrel, potentially representing a new genus and species, is described from the Miocene Gaiman Formation (Argentina) by Piro & Acosta Hospitaleche (2021).{{cite journal|vauthors=Piro A, Acosta Hospitaleche C|year=2021|title=A new petrel (Aves: Procellariidae) from the early Miocene of Patagonia (Argentina)|journal=Historical Biology|volume=34|pages=141–151|doi=10.1080/08912963.2021.1903891|s2cid=233616270}}
• A study on the anatomy and pneumaticity of the skull and on the paleoneurology of the fossil banded penguin Spheniscus urbinai is published by Acosta Hospitaleche, Paulina-Carabajal & Yury-Yáñez (2021).{{cite journal|vauthors=Acosta Hospitaleche C, Paulina-Carabajal A, Yury-Yáñez R|date=February 2021|title=The skull of the Miocene Spheniscus urbinai (Aves, Sphenisciformes): osteology, brain morphology, and the cranial pneumatic systems|journal=Journal of Anatomy|volume=239|issue=1|pages=151–166|doi=10.1111/joa.13403|pmc=8197947|pmid=33576081|s2cid=231901493}}
• A study on the new referred material of Dryornis pampeanus from the Pliocene Chapadmalal Formation (Argentina) and on the phylogenetic relationships of this species is published by Degrange et al. (2021), who interpret D. pampeanus as the largest cathartiform reported to date.{{cite journal|vauthors=Degrange FJ, Tambussi CP, Taglioretti ML, Scaglia FA|year=2021|title=Phylogenetic affinities and morphology of the Pliocene cathartiform Dryornis pampeanus Moreno & Mercerat|journal=Papers in Palaeontology|volume=7|issue=4|pages=1765–1780|doi=10.1002/spp2.1361|bibcode=2021PPal....7.1765D |s2cid=234850849}}
• The first unequivocal fossil material of teratorns from the Pleistocene of South America is described from four fossiliferous localities of Central Argentina by Cenizo et al. (2021), who evaluate the implications of these fossils for the knowledge of the evolutionary history of teratorns, and update the taxonomy of the family.{{cite journal|vauthors=Cenizo M, Noriega JI, Vezzosi RI, Tassara D, Tomassini R|year=2021|title=First Pleistocene South American Teratornithidae (Aves): new insights into the late evolutionary history of teratorns|journal=Journal of Vertebrate Paleontology|volume=41|issue=2|pages=e1927064|doi=10.1080/02724634.2021.1927064|bibcode=2021JVPal..41E7064C |s2cid=237517977|doi-access=free}}
• A study on the feeding capabilities and behaviour of the Haast's eagle is published by van Heteren et al. (2021).{{cite journal|vauthors=van Heteren AH, Wroe S, Tsang LR, Mitchell DR, Ross P, Ledogar JA, Attard MR, Sustaita D, Clausen P, Scofield RP, Sansalone G|year=2021|title=New Zealand's extinct giant raptor (Hieraaetus moorei) killed like an eagle, ate like a condor|journal=Proceedings of the Royal Society B: Biological Sciences|volume=288|issue=1964|pages=Article ID 20211913|doi=10.1098/rspb.2021.1913|pmid=34847767|pmc=8634616}}
• Description of a partial skeleton of a member of the genus Septencoracias from the Eocene London Clay (United Kingdom), belonging or related to the species S. morsensis, and a study on the phylogenetic affinities and likely ecology of this bird is published by Mayr (2021).{{cite journal|vauthors=Mayr G|year=2021|title=A partial skeleton of Septencoracias from the early Eocene London Clay reveals derived features of bee-eaters (Meropidae) in a putative stem group roller (Aves, Coracii)|journal=Palaeobiodiversity and Palaeoenvironments|volume=102|issue=2 |pages=449–463 |doi=10.1007/s12549-021-00504-0|doi-access=free}}
• Redescription of the type specimen of Macrornis tanaupus from the Eocene Totland Bay Formation (Hampshire, United Kingdom) is published by Buffetaut & Angst (2021), who interpret this fossil as a partial tibiotarsus of a large terrestrial bird, possibly a phorusrhacid.{{cite journal|vauthors=Buffetaut E, Angst D|year=2021|title=Macrornis tanaupus Seeley, 1866: an enigmatic giant bird from the upper Eocene of England|journal=Geological Magazine|volume=158|issue=6|pages=1129–1134|bibcode=2021GeoM..158.1129B|doi=10.1017/S0016756820001466|s2cid=226430023}}
• A review of the knowledge of phorusrhacid skull anatomy is presented by Degrange (2021).{{cite journal|vauthors=Degrange FJ|year=2021|title=A Revision of Skull Morphology In Phorusrhacidae (Aves, Cariamiformes)|journal=Journal of Vertebrate Paleontology|volume=40|issue=6|pages=e1848855|doi=10.1080/02724634.2020.1848855|s2cid=234119602}}
• Mayr, De Pietri & Scofield (2021) describe new fossil material of birds from the Eocene Nanjemoy Formation (Virginia, United States), including the first representatives of the families Messelasturidae, Psittacopedidae and Zygodactylidae from this formation.{{cite journal|vauthors=Mayr G, De Pietri V, Scofield RP|year=2021|title=New bird remains from the early Eocene Nanjemoy Formation of Virginia (USA), including the first records of the Messelasturidae, Psittacopedidae, and Zygodactylidae from the Fisher/Sullivan site|journal=Historical Biology|volume=34|issue=2|pages=322–334|doi=10.1080/08912963.2021.1910820|s2cid=234869631|doi-access=free}}
• Two passerine specimens representing different size classes (thrush-sized and sylvid-sized), providing information on skeletal element proportions of the middle Miocene passerines, are described from the Miocene of Austria by Happ et al. (2021).{{cite journal|vauthors=Happ J, Elsler A, Kriwet J, Pfaff C, Bocheński ZM|year=2021|title=Two passeriform birds (Aves: Passeriformes) from the Middle Miocene of Austria|journal=PalZ|volume=96|issue=2 |pages=313–321 |doi=10.1007/s12542-021-00579-2|doi-access=free}}
• A distal end of the left tarsometatarsus of a phasianid, which represents the first avian fossil record of Taiwan, is described from the Pleistocene Chiting Formation (Tainan, Taiwan) by Tsai & Mayr (2021).{{cite journal|vauthors=Tsai CH, Mayr G|year=2021|title=A phasianid bird from the Pleistocene of Tainan: the very first avian fossil from Taiwan|journal=Journal of Ornithology|volume=162|issue=3|pages=919–923|doi=10.1007/s10336-021-01886-w|s2cid=234872494|doi-access=free|bibcode=2021JOrni.162..919T }}
• A study on the mechanics of egg incubation by giant extinct birds is published by Yen et al. (2021).{{cite journal |last1=Yen |first1=An |last2=Wu |first2=Hsiao-Jou |last3=Chen |first3=Pin-Yi |last4=Yu |first4=Hon-Tsen |last5=Juang |first5=Jia-Yang |title=Egg Incubation Mechanics of Giant Birds |journal=Biology |date=2021 |volume=10 |issue=8 |pages=738 |doi=10.3390/biology10080738 |pmid=34439970 |pmc=8389601 |doi-access=free }}
• Revision of the fossil material of birds from Miocene localities in the Iberian Peninsula is published by Sánchez-Marco (2021).{{cite journal|author=Sánchez-Marco A|year=2021|title=Old and new fossil birds from the Spanish Miocene|journal=Journal of Iberian Geology|volume=47|issue=4|pages=697–712|doi=10.1007/s41513-021-00178-9|bibcode=2021JIbG...47..697S |s2cid=238262333|url=https://ddd.uab.cat/record/250772 }}
• Ramírez-Castro & Reynoso (2021) report fossil material of a shelduck and a ringed kingfisher from the Chapala-Zacoalco basins (Mexico), providing new information on the distribution of these birds in the Late Pleistocene.{{cite journal|vauthors=Ramírez-Castro JM, Reynoso VH|year=2021|title=New bird records for the Late Pleistocene of the American continent recovered in Central México and their paleogeographic implications|journal=Journal of South American Earth Sciences|volume=112, Part 1|pages=Article 103578|bibcode=2021JSAES.11203578R|doi=10.1016/j.jsames.2021.103578|s2cid=241213068|doi-access=free}}
• An assemblage of bird bones dated to late Pleistocene through middle Holocene is described from the Istykskaya cave (Pamir Mountains; Tajikistan) by Zelenkov, Sayfulloev, Shnaider (2021), who report the presence of bones of the water rail and a species of Podiceps (the black-necked grebe or the horned grebe) which were not recorded at such high altitudes before, and interpret this finding as evidence of milder environmental conditions in Eastern Pamir during late Quaternary.{{cite journal|vauthors=Zelenkov N, Sayfulloev N, Shnaider SV|year=2021|title=Fossil birds from the Roof of the World: The first avian fauna from High Asia and its implications for late Quaternary environments in Eastern Pamir|journal=PLOS ONE|volume=16|issue=10|pages=e0259151|doi=10.1371/journal.pone.0259151|pmc=8550366|pmid=34705889|bibcode=2021PLoSO..1659151Z|doi-access=free}}
• A study on the sensory systems in extant kiwis and the kākāpō and extinct moa and elephant birds is published by Johnston & Mitchell (2021).{{cite journal|vauthors=Johnston P, Mitchell KJ|year=2021|title=Contrasting Patterns of Sensory Adaptation in Living and Extinct Flightless Birds|journal=Diversity|volume=13|issue=11|pages=Article 538|doi=10.3390/d13110538|doi-access=free|bibcode=2021Diver..13..538J }}
• A study aiming to determine the impact of global climatic changes during the last 120,000 years on Afro-Palearctic migrant birds, as indicated by paleoclimate data and genomic-based estimates of effective population size, is published by Thorup et al. (2021).{{cite journal|vauthors=Thorup K, Pedersen L, da Fonseca RR, Naimi B, Nogués-Bravo D, Krapp M, Manica A, Willemoes M, Sjöberg S, Feng S, Chen G, Rey-Iglesia A, Campos PF, Beyer R, Araújo MB, Hansen AJ, Zhang G, Tøttrup AP, Rahbek C|year=2021|title=Response of an Afro-Palearctic bird migrant to glaciation cycles|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=118|issue=52|pages=e2023836118|doi=10.1073/pnas.2023836118|pmid=34949638|pmc=8719893|bibcode=2021PNAS..11823836T |s2cid=245445221|doi-access=free }}

• A study aiming to determine the nature and average number of osteological characters used to diagnose pterosaur species, as well as aiming to estimate how many pterosaur taxa are still unknown, is published by Fernandes, Nunes & Costa (2021).{{cite journal | vauthors = Fernandes DL, Nunes I, Costa FR | title = A taxonomic approach on diagnostic characters used to define new pterosaur taxa and an estimation of pterosaur diversity | journal = Anais da Academia Brasileira de Ciências | volume = 93 | issue = suppl 2 | pages = e20201568 | year = 2021 | doi = 10.1590/0001-3765202120201568 | pmid = 34550166 | s2cid = 237594498 | doi-access = free }}
• A study on the phylogenetic affinities of pterosaurs is published by Baron (2021).{{cite journal | vauthors = Baron MG | title = The origin of pterosaurs | journal = Earth-Science Reviews | volume = 221 | pages = Article 103777 | year = 2021 | doi = 10.1016/j.earscirev.2021.103777 | bibcode = 2021ESRv..22103777B }}
• A study on the flight abilities of hatchling pterosaurs is published by Naish, Witton & Martin-Silverstone (2021).{{cite journal| vauthors = Naish D, Witton MP, Martin-Silverstone E |title=Powered flight in hatchling pterosaurs: evidence from wing form and bone strength |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 13130 |doi=10.1038/s41598-021-92499-z |pmid=34294737 |pmc=8298463 |bibcode=2021NatSR..1113130N | doi-access = free }}
• A study on size range of pterosaurs from the Cretaceous Kem Kem Group (Morocco) and on the bone histology of small pterosaur specimens from these strata is published by Smith et al. (2021), who interpret their findings as indicating that in the Cretaceous period the niches previously occupied by small pterosaurs were increasingly occupied by early ontogenetic stages of large pterosaurs rather than by birds.{{cite journal | vauthors = Smith RE, Chinsamy A, Unwin DM, Ibrahim N, Zouhri S, Martill DM | title = Small, immature pterosaurs from the Cretaceous of Africa: implications for taphonomic bias and palaeocommunity structure in flying reptiles | journal = Cretaceous Research | volume = 130 | pages = Article 105061 | year = 2021 | doi = 10.1016/j.cretres.2021.105061 | s2cid = 239257717 | url = https://www.sciencedirect.com/science/article/abs/pii/S0195667121003098 }}
• New information on the skeletal anatomy of Austriadraco dallavecchiai is provided by Dalla Vecchia (2021).{{cite journal | vauthors = Dalla Vecchia FM | title = A revision of the anatomy of the Triassic pterosaur Austriadraco dallavecchiai Kellner, 2015 and of its diagnosis | journal = Rivista Italiana di Paleontologia e Stratigrafia | volume = 127 | issue = 2 | pages = 427–452 | year = 2021 | doi = 10.13130/2039-4942/15849 }}
• Fossil material of a rhamphorhynchine pterosaur is described from the Upper Jurassic Cerro Campamento Formation (Chile) by Alarcón-Muñoz et al. (2021), representing the first record of this group from Gondwana reported to date.{{cite journal | vauthors = Alarcón-Muñoz J, Otero RA, Soto-Acuña S, Vargas AO, Rojas J, Rojas O | title = First record of a Late Jurassic rhamphorhynchine pterosaur from Gondwana | journal = Acta Palaeontologica Polonica | volume = 66 | issue = 3 | pages = 571–583 | year = 2021 | doi = 10.4202/app.00805.2020| s2cid = 239726523 | doi-access = free }}
• An early juvenile or late hatchling specimen of Kunpengopterus sinensis, providing new information on the skeletal changes during ontogeny in wukongopterids, is described from the Tiaojishan Formation (China) by Jiang et al. (2021).{{cite journal | vauthors = Jiang S, Wang X, Zheng X, Cheng X, Zhang J, Wang X | title = An early juvenile of Kunpengopterus sinensis (Pterosauria) from the Late Jurassic in China | journal = Anais da Academia Brasileira de Ciências | volume = 93 | issue = suppl 2 | pages = e20200734 | year = 2021 | pmid = 33886742 | doi = 10.1590/0001-3765202120200734 | s2cid = 233371329 | doi-access = free }}
• Pêgas, Costa & Kellner (2021) attempt to reconstruct the adductor musculature of the pterodactyloid skull, and to estimate bite force for nine pterodactyloid species.{{cite journal| vauthors = Pêgas RV, Costa FR, Kellner AW |title=Reconstruction of the adductor chamber and predicted bite force in pterodactyloids (Pterosauria) |year=2021 |journal=Zoological Journal of the Linnean Society |volume=193 |issue=2 |pages=602–635 |doi=10.1093/zoolinnean/zlaa163 }}
• A study on soft tissues of a pterodactyloid specimen from the Upper Jurassic Solnhofen Limestones (Germany) is published by Pittman et al. (2021), who interpret their findings as providing evidence of the presence of a biological wing root fairing in pterosaurs.{{cite journal | vauthors = Pittman M, Barlow LA, Kaye TG, Habib MB | title = Pterosaurs evolved a muscular wing–body junction providing multifaceted flight performance benefits: Advanced aerodynamic smoothing, sophisticated wing root control, and wing force generation | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 118 | issue = 44 | pages = e2107631118 | year = 2021 | doi = 10.1073/pnas.2107631118 | doi-access = free | pmid = 34663691 | pmc = 8612209 | bibcode = 2021PNAS..11807631P }}
• A well-preserved large skull of Ctenochasma elegans is described from the Upper Jurassic Painten Formation (Germany) by Bennett (2021).{{Cite journal|last=Bennett |first=S. C. |title=Complete large skull of the pterodactyloid pterosaur Ctenochasma elegans from the Late Jurassic Solnhofen Lithographic Limestones |year=2021 |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=301 |issue=3 |pages=283–294 |doi=10.1127/njgpa/2021/1011 |s2cid=239649715 }}
• Partial mandible of Forfexopterus is described from the Early Cretaceous Jehol Biota (China) by Zhou, Wang & Wang (2021), who report evidence of tooth wear in this specimen, making it the first known record of tooth-tooth occlusion in ctenochasmatids, and evaluate its implications for the knowledge of the feeding strategy of ctenochasmatids.{{cite book |last1=Zhou |first1=C.-F. |last2=Wang |first2=X. |last3=Wang |first3=J. |year=2021 |chapter=First evidence for tooth-tooth occlusion in a ctenochasmatid pterosaur from the Early Cretaceous Jehol Biota |editor1=S-C. Chang |editor2=D. Zheng |title=Mesozoic Biological Events and Ecosystems in East Asia |series=Geological Society, London, Special Publications |volume=521 |pages=9–17 |publisher=The Geological Society of London |doi=10.1144/SP521-2021-141 |s2cid=244695072 }}
• Fragment of an ulna of a pteranodontid pterosaur is described from the Campanian locality Polunino 2 (Volgograd Oblast, Russia) by Averianov & Yarkov (2021), representing the first record of the family Pteranodontidae from the Lower Volga region reported so far.{{cite journal| vauthors = Averianov AO, Yarkov AA |title=The first record of a pteranodontid (Pterosauria, Pteranodontidae) from the Late Cretaceous of the Lower Volga Region |year=2021 |journal=Paleontological Journal |volume=55 |issue=1 |pages=101–104 |doi=10.1134/S0031030121010032|bibcode=2021PalJ...55..101A | issn=0031-0301 |s2cid=232070839 |url=https://www.elibrary.ru/item.asp?id=44492502 |url-access=subscription }}
• A review of putative boreopterid pterosaurs from the South Korea was published by Yun (2021), who concluded that they could not be confidently referred to Boreopteridae.{{cite journal| vauthors = Yun CG |title=Boreopterid pterosaur fossils from South Korea reconsidered |year=2021 |journal=New Mexico Museum of Natural History and Science Bulletin |volume=82 |pages=567–568 |url=https://www.researchgate.net/publication/347993219 }}
• New specimen of Istiodactylus latidens, probably coming from the Lower Cretaceous Vectis Formation (United Kingdom) and possibly representing the missing jaws of the holotype of this species, is described by Averianov et al. (2021).{{cite journal| vauthors = Averianov AO, Kolchanov VV, Zverkov NG, Aleksandrova GN, Yaroshenko OP |title=The wandering jaws of Istiodactylus latidens (Pterosauria, Istiodactylidae) |year=2021 |journal=Cretaceous Research |volume=126 |pages=Article 104887 |doi=10.1016/j.cretres.2021.104887 |bibcode=2021CrRes.12604887A }}
• Bantim et al. (2021) describe a pteranodontoid pterosaur with anhanguerid affinities from Aptian-age deposits of the Romualdo Formation (Brazil).{{cite journal | vauthors = Bantim RA, de Andrade RC, Ferreira JS, Saraiva AÁ, Kellner AW, Sayao JM |year=2021|title=Osteohistology and growth pattern of a large pterosaur from the Lower Cretaceous Romualdo Formation of the Araripe Basin, Northeastern Brazil|journal=Cretaceous Research |volume=118|page=Article 104667|doi=10.1016/j.cretres.2020.104667|bibcode=2021CrRes.11804667B |s2cid=225131416}}
• A new pterodactyloid mandible from the Valanginian of Germany is described by Abel et al. (2021), representing the oldest anhanguerian known to date.{{cite journal|vauthors= Abel P, Kear BP, Hornung JJ, Sachs S|year=2021|title=An anhanguerian pterodactyloid mandible from the lower Valanginian of Northern Germany, and the German record of Cretaceous pterosaurs|journal=Acta Palaeontologica Polonica|volume=66|pages=S5–S12|doi=10.4202/app.00818.2020|s2cid=237335500|doi-access=free}}.
• A study on the variation of pneumaticity patterns in the vertebral column of an anhanguerid specimen from the Romualdo Formation is published by Buchmann et al. (2021).{{cite journal| vauthors = Buchmann R, Holgado B, Sobral G, Avilla LS, Rodrigues T |title=Quantitative assessment of the vertebral pneumaticity in an anhanguerid pterosaur using micro-CT scanning |year=2021 |journal=Scientific Reports |volume=11 |issue=1 |pages=Article number 18718 |doi=10.1038/s41598-021-97856-6 | doi-access = free |pmid=34548510 |pmc=8455612 |bibcode=2021NatSR..1118718B }}
• Solonin et al. (2021) describe teeth from the Upper Cretaceous (Santonian) Dmitrov Formation (Ryazan Oblast, Russia), referrable to ornithocheirid pterosaurs, leading to the first occurrence of them in said formation.{{cite journal |last1=Solonin |first1=Sergey V. |last2=Martill |first2=David M. |last3=Smith |first3=Roy E. |last4=Vodorezov |first4=Alexey V. |title=First occurrence of ornithocheirid pterosaur teeth in the Dmitrov Formation (Santonian) of Ryazan Oblast, Russia |journal=Cretaceous Research |year=2021 |volume=127 |pages=Article 104943 |doi=10.1016/j.cretres.2021.104943 |bibcode=2021CrRes.12704943S }}
• A well-preserved, almost complete and articulated new specimen of Tupandactylus navigans, associated with soft tissue remains, is described from the Lower Cretaceous Crato Formation (Brazil) by Beccari et al. (2021).{{cite journal| vauthors = Beccari V, Pinheiro FL, Nunes I, Anelli LE, Mateus O, Costa FR |title=Osteology of an exceptionally well-preserved tapejarid skeleton from Brazil: Revealing the anatomy of a curious pterodactyloid clade |year=2021 |journal=PLOS ONE |volume=16 |issue=8 |pages=e0254789 |doi=10.1371/journal.pone.0254789 |pmid=34432814 |pmc=8386889 |bibcode=2021PLoSO..1654789B |doi-access=free }}
• New specimen of Sinopterus dongi, improving knowledge on the anatomy of this pterosaur, is described from the Lower Cretaceous Jiufotang Formation (China) by Shen et al. (2021).{{cite journal| vauthors = Shen C, Pêgas RV, Gao C, Kundrát M, Zhang L, Wei X, Zhou X |title=A new specimen of Sinopterus dongi (Pterosauria, Tapejaridae) from the Jiufotang Formation (Early Cretaceous, China) |year=2021 |journal=PeerJ |volume=9 |pages=e12360 |doi=10.7717/peerj.12360 |pmid=34760376 |pmc=8559606 |doi-access=free }}
• Partial femur of a large-sized dsungaripteroid pterosaur is described from the Upper Jurassic (Kimmeridgian) Praia da Amoreira–Porto Novo Formation (Portugal) by Bertozzo et al. (2021), representing the second confirmed report of a dsungaripteroid from the Jurassic, and the first record of this group from the Iberian Peninsula reported to date.{{cite journal | vauthors = Bertozzo F, Camilo Da Silva B, Martill D, Vorderwuelbecke EM, Aureliano T, Schouten R, Aquino P | title = A large pterosaur femur from the Kimmeridgian, Upper Jurassic of Lusitanian Basin, Portugal | journal = Acta Palaeontologica Polonica | volume = 66 | issue = 4 | pages = 815–825 | year = 2021 | doi = 10.4202/app.00858.2020 | s2cid = 243825717 | doi-access = free }}
• Postcranial elements referrable to Lonchognathosaurus, confirming the validity of the genus and providing new information on the anatomy of this pterosaur, are described from the Lower Cretaceous Lianmuqin Formation (China) by Augustin et al. (2021).{{cite journal| vauthors = Augustin FJ, Matzke AT, Maisch MW, Pfretzschner HU |title=New information on Lonchognathosaurus (Pterosauria: Dsungaripteridae) from the Lower Cretaceous of the southern Junggar Basin (NW China) |year=2021 |journal=Cretaceous Research |volume=124 |pages=Article 104808 |url=https://www.sciencedirect.com/science/article/abs/pii/S0195667121000550 |doi=10.1016/j.cretres.2021.104808 |bibcode=2021CrRes.12404808A |s2cid=233790566 |url-access=subscription }}
• 114 small pterosaur footprints, possibly produced by pterosaurs belonging to the species Noripterus complicidens, are described from the Lower Cretaceous Shengjinkou Formation (China) by Li, Wang & Jiang (2021), who name a new ichnospecies Pteraichnus wuerhoensis.{{cite journal | vauthors = Li Y, Wang X, Jiang S |year=2021 |title=A new pterosaur tracksite from the Lower Cretaceous of Wuerho, Junggar Basin, China: inferring the first putative pterosaur trackmaker |journal=PeerJ |volume=9 |pages=e11361 |doi=10.7717/peerj.11361 |pmid=34131515 |pmc=8176908 |doi-access=free }}
• New fossil material of pterosaurs is described from the Lower Cretaceous Lianmuqin Formation (China) by Augustin et al. (2021), who interpret these fossils as probable evidence of the presence of a second dsungaripterid taxon (distinct from Lonchognathosaurus) in this formation.{{cite journal| vauthors = Augustin FJ, Matzke AT, Maisch MW, Csiki-Sava Z |year=2021 |title=Pterosaur remains from the Lower Cretaceous Lianmuxin Formation (upper Tugulu Group) of the southern Junggar Basin (NW China) |journal=Historical Biology |volume=34 |issue=2 |pages=312–321 |doi=10.1080/08912963.2021.1910819 |s2cid=233597623 }}
• New fossil material of dsungaripterids is described from the Lower Cretaceous Hutubei Formation (China) by Augustin et al. (2021), representing the first record of pterosaurs from this formation reported to date, and one of the oldest records of dsungaripterids from the Tugulu Group.{{cite journal | vauthors = Augustin FJ, Matzke AT, Maisch MW, Kampouridis P, Csiki-Sava Z | title = The first record of pterosaurs from the Lower Cretaceous Hutubei Formation (lower Tugulu Group) of the southern Junggar Basin (NW China) – a glimpse into an unusual ecosystem | journal = Cretaceous Research | volume = 130 | pages = Article 105066 | year = 2021 | doi = 10.1016/j.cretres.2021.105066 | s2cid = 239518703 | url = https://www.sciencedirect.com/science/article/abs/pii/S0195667121003141 | url-access = subscription }}
• A study on the internal architecture and mechanical properties of a hyper-elongate cervical vertebra of an azhdarchid pterosaur from the Kem Kem Group (Morocco) is published by Williams et al. (2021).{{cite journal| vauthors = Williams CJ, Pani M, Bucchi A, Smith RE, Kao A, Keeble W, Ibrahim N, Martill DM |title=Helically arranged cross struts in azhdarchid pterosaur cervical vertebrae and their biomechanical implications |year=2021 |journal=iScience |volume=24 |issue=4 |pages=Article 102338 |doi=10.1016/j.isci.2021.102338 |pmid=33997669 |pmc=8101050 |bibcode=2021iSci...24j2338W }}
• Fragment of the wing metacarpal of an azhdarchid is described from the Campanian of the Orenburg Oblast (Russia) by Averianov, Zverkov & Nikiforov (2021), representing the first record of a pterosaur from the Late Cretaceous of Southern Urals reported to date.{{cite journal| vauthors = Averianov AO, Zverkov NG, Nikiforov AV |year=2021 |title=First finding of a pterosaur in the Upper Cretaceous of the Southern Urals |journal=Paleontological Journal |volume=55 |issue=6 |pages=678–683 |doi=10.1134/S0031030121060034 |bibcode=2021PalJ...55..678A |s2cid=245010400 |url=https://www.elibrary.ru/item.asp?id=46621799 |url-access=subscription }}
• A study on the anatomy and phylogenetic affinities of Aerotitan sudamericanus is published by Pêgas et al. (2021; final version published in 2022), who name the new clades Azhdarchomorpha and Alanqidae.{{cite journal | vauthors = Pêgas RV, Holgado B, Ortiz David LD, Baiano MA, Costa FR | title = On the pterosaur Aerotitan sudamericanus (Neuquén Basin, Upper Cretaceous of Argentina), with comments on azhdarchoid phylogeny and jaw anatomy | journal = Cretaceous Research | volume = 129 | pages = Article 104998 | year = 2022 | doi = 10.1016/j.cretres.2021.104998 | bibcode = 2022CrRes.12904998P | s2cid = 238725853 }}
• A large wing bone (possibly an ulna) of a pterosaur with an estimated wingspan comparable with the holotype specimen of Cryodrakon boreas is described from the Campanian Kaiparowits Formation (Utah, United States) by Farke (2021).{{cite journal | vauthors = Farke AA | title = A large pterosaur limb bone from the Kaiparowits Formation (late Campanian) of Grand Staircase-Escalante National Monument, Utah, USA | journal = PeerJ | volume = 9 | pages = e10766 | year = 2021 | pmid = 33552741 | pmc = 7825364 | doi = 10.7717/peerj.10766 | doi-access = free }}
• Studies on the paleoenvironment, functional morphology, and the phylogenetic affinities of Quetzalcoatlus, which also focuses on the phylogeny of pterosaurs in general and names the new clades Azhdarchiformes, Nyctosauromorpha and Ornithocheiriformes are published by Lehman et al. (2021),{{Cite journal|last=Lehman|first=Thomas M.|date=2021-12-14|title=Habitat of the giant pterosaur Quetzalcoatlus Lawson 1975 (Pterodactyloidea: Azhdarchoidea): a paleoenvironmental reconstruction of the Javelina Formation (Upper Cretaceous) Big Bend National Park, Texas|journal=Journal of Vertebrate Paleontology|volume=41|issue=sup1|pages=21–45|doi=10.1080/02724634.2019.1593184|bibcode=2021JVPal..41S..21L |s2cid=245009158|issn=0272-4634|doi-access=free}} Padian et al. (2021){{Cite journal|last1=Padian|first1=Kevin|last2=Cunningham|first2=James R.|last3=Langston|first3=Wann|last4=Conway|first4=John|date=2021-12-14|title=Functional morphology of Quetzalcoatlus Lawson 1975 (Pterodactyloidea: Azhdarchoidea)|journal=Journal of Vertebrate Paleontology|volume=41|issue=sup1|pages=218–251|doi=10.1080/02724634.2020.1780247|bibcode=2021JVPal..41S.218P |s2cid=245125427|issn=0272-4634|doi-access=free}} and Andres (2021).{{Cite journal|last=Andres|first=Brian|date=2021-12-14|title=Phylogenetic systematics of Quetzalcoatlus Lawson 1975 (Pterodactyloidea: Azhdarchoidea)|journal=Journal of Vertebrate Paleontology|volume=41|issue=sup1|pages=203–217|doi=10.1080/02724634.2020.1801703|bibcode=2021JVPal..41S.203A |s2cid=245078533|issn=0272-4634|doi-access=free}}

• Marchetti et al. (2021) revise the tetrapod (including dinosauromorph) footprint assemblage from the Quarziti del Monte Serra Formation (Ladinian of Italy), and interpret this assemblage and other findings of Ladinian dinosauromorph footprints as evidence of wide dispersal of dinosauromorphs as early as the Middle Triassic.{{cite journal | vauthors = Marchetti L, Collareta A, Belvedere M, Leonardi G |year=2021 |title=Ichnotaxonomy, biostratigraphy and palaeoecology of the Monti Pisani tetrapod ichnoassociation (Tuscany, Italy) and new insights on Middle Triassic Dinosauromorpha |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=567 |pages=Article 110235 |doi=10.1016/j.palaeo.2021.110235 |bibcode=2021PPP...56710235M |s2cid=233530709 }}
• The first putative forelimb and pectoral girdle of Lagerpeton chanarensis is described by McCabe & Nesbitt (2021).{{cite journal| vauthors = McCabe MB, Nesbitt SJ |title=The first pectoral and forelimb material assigned to the lagerpetid Lagerpeton chanarensis (Archosauria: Dinosauromorpha) from the upper portion of the Chañares Formation, Late Triassic |year=2021 |journal=Palaeodiversity |volume=14 |issue=1 |pages=121–131 |doi=10.18476/pale.v14.a5 |doi-access=free }}
• A study on the nature of tooth attachment in silesaurids, and on its implications of the knowledge of the evolution of tooth attachment of archosaurs, is published by Mestriner et al. (2021).{{cite journal| vauthors = Mestriner G, LeBlanc A, Nesbitt SJ, Marsola JC, Irmis, RB, Da-Rosa ÁA, Ribeiro AM, Ferigolo J, Langer M |title=Histological analysis of ankylothecodonty in Silesauridae (Archosauria: Dinosauriformes) and its implications for the evolution of dinosaur tooth attachment |year=2021 |journal=The Anatomical Record |volume=305 |issue=2 |pages=393–423 |doi=10.1002/ar.24679 |pmid=34021739 |s2cid=235094106 |doi-access=free }}
• Two partial skeletons of Lewisuchus admixtus, providing new information on the anatomy of this dinosauriform, are described from the Chañares Formation (Argentina) by Agnolín et al. (2021).{{cite journal| vauthors = Agnolín F, Brissón Egli F, Ezcurra MD, Langer MC, Novas F |title=New specimens provide insights into the anatomy of the dinosauriform Lewisuchus admixtus Romer, 1972 from the Upper Triassic levels of the Chañares Formation, Nw Argentina |year=2021 |journal=The Anatomical Record |volume=305 |issue=5 |pages=1119–1146 |doi=10.1002/ar.24731 |pmid=34358415 |s2cid=236945638 }}

• A study on the relationship between full potential joint mobility and the poses used during locomotion in extant American alligator and helmeted guineafowl, evaluating its implications for reconstructions of locomotion of extinct archosaurs, is published by Manafzadeh, Kambic, and Gatesy (2021).{{cite journal | vauthors = Manafzadeh AR, Kambic RE, Gatesy SM | title = A new role for joint mobility in reconstructing vertebrate locomotor evolution | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 118 | issue = 7 | pages = e2023513118 | date = February 2021 | pmid = 33558244 | pmc = 7896293 | doi = 10.1073/pnas.2023513118 | bibcode = 2021PNAS..11820235M | doi-access = free }}
• A study on the femoral shape variation and on the relationship between femoral morphology and locomotor habits in early archosaurs and non-archosaur archosauriforms is published by Pintore et al. (2021).{{Cite journal|last1=Pintore |first1=R. |last2=Houssaye |first2=A. |last3=Nesbitt |first3=S. J. |last4=Hutchinson |first4=J. R. |year=2021 |title=Femoral specializations to locomotor habits in early archosauriforms |journal=Journal of Anatomy |volume=240 |issue=5 |pages=867–892 |doi=10.1111/joa.13598 |pmid=34841511 |pmc=9005686 |s2cid=244752006 }}
• A study estimating moment arms for major pelvic limb muscles in extant and fossil archosaurs, aiming to investigate the idea that bird-line archosaurs switched from hip-based to knee-based locomotion between Archosauria (especially Neotheropoda) and Aves, is published by Allen, Kilbourne & Hutchinson (2021).{{cite journal | vauthors = Allen VR, Kilbourne BM, Hutchinson JR | title = The evolution of pelvic limb muscle moment arms in bird-line archosaurs | journal = Science Advances | volume = 7 | issue = 12 | pages = eabe2778 | date = March 2021 | pmid = 33741593 | pmc = 7978429 | doi = 10.1126/sciadv.abe2778 | bibcode = 2021SciA....7.2778A }}
• A study aiming to determine how ontogenetic changes in skeletal anatomy influence muscle size, leverage, orientation, and locomotor function during the development of flight in extant chukar partridge is published by Heers et al. (2021), who evaluate the implications of their findings on current knowledge of how extinct winged theropods might have achieved bird-like behaviors before acquiring fully bird-like anatomies.{{cite journal| vauthors = Heers AM, Varghese SL, Hatier LK, Cabrera JJ |year=2021 |title=Multiple Functional Solutions During Flightless to Flight-Capable Transitions |journal=Frontiers in Ecology and Evolution |volume=8 |pages=Article 573411 |doi=10.3389/fevo.2020.573411 |s2cid=231858466 |doi-access=free }}
• A study on jumping mechanics and performance in extant elegant crested tinamou, and on its implications for inferences of jumping abilities in extinct animals such as dromaeosaurid dinosaurs, is published by Bishop et al. (2021).{{cite journal| vauthors = Bishop PJ, Falisse A, De Groote R, Hutchinson JR |year=2021 |title=Predictive simulations of musculoskeletal function and jumping performance in a generalized bird |journal=Integrative Organismal Biology |volume=3 |issue=1 |pages=obab006 |doi=10.1093/iob/obab006 |pmid=34377939 |pmc=8341896 }}
• A study on the morphological diversity and evolution of the semicircular canals of the inner ear in extant and fossil archosaurs is published by Bronzati et al. (2021).{{cite journal| vauthors = Bronzati M, Benson RB, Evers SW, Ezcurra MD, Cabreira SF, Choiniere J, Dollman KN, Paulina-Carabajal A, Radermacher VJ, Roberto-da-Silva L, Sobral G, Stocker MR, Witmer LM, Langer MC, Nesbitt SJ |year=2021 |title=Deep evolutionary diversification of semicircular canals in archosaurs |journal=Current Biology |volume=31 |issue=12 |pages=2520–2529.e6 |doi=10.1016/j.cub.2021.03.086 |pmid=33930303 |s2cid=233472336 |url=https://ora.ox.ac.uk/objects/uuid:8aa29495-9ca9-41bf-b0e9-0e5b6525e17b |doi-access=free |bibcode=2021CBio...31E2520B }}
• A study on the evolution of eggshell thickness in non-avian dinosaurs and birds is published by Legendre & Clarke (2021).{{cite journal| vauthors = Legendre LJ, Clarke JA |year=2021 |title=Shifts in eggshell thickness are related to changes in locomotor ecology in dinosaurs |journal=Evolution |volume=75 |issue=6 |pages=1415–1430 |doi=10.1111/evo.14245 |pmid=33913155 |s2cid=233448002 }}
• A study on the evolution of birdlike locomotor abilities and hearing acuity, as indicated by the anatomy of the inner ear in extant and fossil reptiles and birds, is published by Hanson et al. (2021);{{cite journal| vauthors = Hanson M, Hoffman EA, Norell MA, Bhullar BA |title=The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization |year=2021 |journal=Science |volume=372 |issue=6542 |pages=601–609 |doi=10.1126/science.abb4305 |pmid=33958471 |bibcode=2021Sci...372..601H |s2cid=233872841 }} the conclusions of the study are subsequently contested by David, Bronzati & Benson (2022).{{cite journal| vauthors = David R, Bronzati M, Benson RB |title=Comment on "The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization" |year=2022 |journal=Science |volume=376 |issue=6600 |pages=eabl6710 |doi=10.1126/science.abl6710 |pmid=35737763 |s2cid=249989812 |url=https://ora.ox.ac.uk/objects/uuid:7bbfeab5-dab6-4de1-9c5b-b2526cbed28c |doi-access=free }}{{cite journal| vauthors = Hanson M, Hoffman EA, Norell MA, Bhullar BA |title=Response to Comment on "The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization" |year=2022 |journal=Science |volume=376 |issue=6600 |pages=eabl8181 |doi=10.1126/science.abl8181 |pmid=35737783 |s2cid=249990447 |doi-access=free }}
• A study assessing the accuracy of bite force estimates in extinct archosaurs and mammals is published by Sakamoto (2021).{{cite journal| vauthors = Sakamoto M |year=2021 |title=Assessing bite force estimates in extinct mammals and archosaurs using phylogenetic predictions |journal=Palaeontology |volume=64 |issue=5 |pages=743–753 |doi=10.1111/pala.12567 |bibcode=2021Palgy..64..743S |doi-access=free }}
• A study on the composition of the assemblage of isolated archosaur (dinosaur and crocodyliform) teeth and osteoderms from the Upper Cretaceous Cerro Fortaleza Formation (Argentina), and on its implications for the knowledge of the archosaur biodiversity in southern Patagonia during the Late Cretaceous, is published by Paulina-Carabajal et al. (2021).{{cite journal| vauthors = Paulina-Carabajal A, Barrios FT, Méndez AH, Cerda IA, Lee YN |title=A Late Cretaceous dinosaur and crocodyliform faunal association–based on isolate teeth and osteoderms–at Cerro Fortaleza Formation (Campanian-Maastrichtian) type locality, Santa Cruz, Argentina |year=2021 |journal=PLOS ONE |volume=16 |issue=9 |pages=e0256233 |doi=10.1371/journal.pone.0256233 |pmid=34495977 |pmc=8425559 |bibcode=2021PLoSO..1656233P |doi-access=free }}
• A study on evolution of the expression of carotenoids in skin and other integumentary structures of archosaurs is published by Davis & Clarke (2021).{{cite journal| vauthors = Davis SN, Clarke JA |year=2021 |title=Estimating the distribution of carotenoid coloration in skin and integumentary structures of birds and extinct dinosaurs |journal=Evolution |volume=76 |issue=1 |pages=42–57 |doi=10.1111/evo.14393 |pmid=34719783 |s2cid=240356095 |url=https://zenodo.org/record/5533001 }}
• A study on the ossification patterns of the respiratory turbinate in extant birds, and on their implications for the identification of the positions and form of possible osteological correlates of the respiratory turbinate in non-avian dinosaurs, is published by Tada & Tsuihiji (2021).{{cite journal| vauthors = Tada S, Tsuihiji T |year=2021 |title=Ossification of the respiratory turbinate in Aves and its implications for non-avian dinosaurs |journal=Bulletin of the National Museum of Nature and Science, Series C |volume=47 |pages=53–59 |doi=10.50826/bnmnsgeopaleo.47.0_53 |url=https://www.kahaku.go.jp/research/publication/geology/download/47/BNMNS_C47_53.pdf }}
• Revision of the Mesozoic and Cenozoic record of large, unwebbed bird and bird-like footprints is published by Lockley, Abbassi & Helm (2021).{{Cite journal|last1=Lockley |first1=M. G. |last2=Abbassi |first2=N. |last3=Helm |first3=C. W. |year=2021 |title=Large, unwebbed bird and bird-like footprints from the Mesozoic and Cenozoic: a review of ichnotaxonomy and trackmaker affinity |journal=Lethaia |volume=54 |issue=5 |pages=969–987 |doi=10.1111/let.12458 |bibcode=2021Letha..54..969L |s2cid=245606075 }}

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Category:Archosaurs

Category:2021 in paleontology