2019 in arthropod paleontology

• A revision of higher-level arthropod taxonomy is published by Aria (2019), who proposes the name Cenocondyla for the least inclusive group containing both Mandibulata and Chelicerata.{{Cite journal|author=Cédric Aria |year=2019 |title=Reviewing the bases for a nomenclatural uniformization of the highest taxonomic levels in arthropods |journal=Geological Magazine |volume=156 |issue=8 |pages=1463–1468 |doi=10.1017/S0016756819000475 |bibcode=2019GeoM..156.1463A |s2cid=189983562 }}
• A study on the molecular composition and microanatomy of the eyes of 54-million-year-old crane flies from the Fur Formation (Denmark), evaluating its implications for the knowledge of optical systems of other ancient arthropods (especially trilobites), is published by Lindgren et al. (2019).{{Cite journal|author1=Johan Lindgren |author2=Dan-Eric Nilsson |author3=Peter Sjövall |author4=Martin Jarenmark |author5=Shosuke Ito |author6=Kazumasa Wakamatsu |author7=Benjamin P. Kear |author8=Bo Pagh Schultz |author9=René Lyng Sylvestersen |author10=Henrik Madsen |author11=James R. LaFountain Jr |author12=Carl Alwmark |author13=Mats E. Eriksson |author14=Stephen A. Hall |author15=Paula Lindgren |author16=Irene Rodríguez-Meizoso |author17=Per Ahlberg |year=2019 |title=Fossil insect eyes shed light on trilobite optics and the arthropod pigment screen |journal=Nature |volume=573 |issue=7772 |pages=122–125 |doi=10.1038/s41586-019-1473-z |pmid=31413368 |bibcode=2019Natur.573..122L |s2cid=199577084 |url=https://lup.lub.lu.se/record/a72dafb0-6b95-4e45-9895-ea6c967862e0 }}

• Two new specimens of laniatorid harvestmen (an adult specimen assignable to the species Proholoscotolemon nemastomoides and a smaller specimen belonging or related to the genus Proholoscotolemon) are described from the Eocene Baltic amber by Bartel & Dunlop (2019).{{Cite journal|author1=Christian Bartel |author2=Jason A. Dunlop |year=2019 |title=Two laniatorid harvestmen (Opiliones: Cladonychiidae) from Eocene Baltic amber |journal=Arachnologische Mitteilungen: Arachnology Letters |volume=58 |issue=1 |pages=9–12 |doi=10.30963/aramit5804 |s2cid=201665336 |doi-access=free }}
• A review of the phylogenetic hypotheses of scorpion interrelationships, as well as of scorpion palaeontology, is published by Howard et al. (2019), who also provide a list of scorpion fossil calibrations for use in molecular dating.{{Cite journal|author1=Richard J. Howard|author2=Gregory D. Edgecombe|author3=David A. Legg|author4=Davide Pisani|author5=Jesus Lozano-Fernandez|year=2019|title=Exploring the evolution and terrestrialization of scorpions (Arachnida: Scorpiones) with rocks and clocks|url=https://link.springer.com/content/pdf/10.1007%2Fs13127-019-00390-7.pdf|journal=Organisms Diversity & Evolution|volume=19|issue=1|pages=71–86|doi=10.1007/s13127-019-00390-7|doi-access=free}}
• A fossil spider, possibly a juvenile female golden silk orb-weaver, is described from the Lower Eocene Palana Formation of the Gurha opencast lignite mine (western Rajasthan, India) by Patel, Rana & Selden (2019), representing the first fossil spider from India which wasn't found in amber.{{Cite journal|author1=Raman Patel |author2=Rajendra Singh Rana |author3=Paul A. Selden |year=2019 |url= http://www.paulselden.net/uploads/7/5/3/2/7532217/indiannephila2019.pdf |title=An orb-weaver spider (Araneae, Araneidae) from the early Eocene of India |journal=Journal of Paleontology |volume=93 |issue=1 |pages=98–104 |doi=10.1017/jpa.2018.71 |bibcode=2019JPal...93...98P |s2cid=115144220 |archive-url=https://web.archive.org/web/20190429170809/http://www.paulselden.net/uploads/7/5/3/2/7532217/indiannephila2019.pdf |archive-date=2019-04-29 }}
• A review of the fossil record and evolutionary history of spiders, reevaluating the phylogenetic placement of key fossils and aiming to determine whether there has been a major turnover in the spider fauna between the Mesozoic and Cenozoic, is published online by Magalhaes et al. (2019).{{Cite journal|author1=Ivan L. F. Magalhaes |author2=Guilherme H. F. Azevedo |author3=Peter Michalik |author4=Martín J. Ramírez |year=2019 |title=The fossil record of spiders revisited: implications for calibrating trees and evidence for a major faunal turnover since the Mesozoic |journal=Biological Reviews |volume=95 |issue=1 |pages=184–217 |doi=10.1111/brv.12559 |pmid=31713947 |s2cid=207937170 }}

• A global dataset of exceptionally preserved muscles and muscle attachment scars in fossil malacostracan specimens is compiled by Klompmaker et al. (2019).{{Cite journal|author1=Adiël A. Klompmaker |author2=Matúš Hyžný |author3=Roger W. Portell |author4=Clément Jauvion |author5=Sylvain Charbonnier |author6=Shane S. Fussell |author7=Aaron T. Klier |author8=Raymond Tejera |author9=Sten Jakobsen |year=2019 |title=Muscles and muscle scars in fossil malacostracan crustaceans |journal=Earth-Science Reviews |volume=194 |pages=306–326 |doi=10.1016/j.earscirev.2019.04.012 |bibcode=2019ESRv..194..306K |s2cid=128354711 }}
• A three-dimensionally preserved tanaidacean specimen belonging or related to the species Jurapseudes friedericianus is described from the Middle Jurassic (Callovian) Ornatenton Formation (Germany) by Schädel et al. (2019).{{Cite journal|author1=Mario Schädel |author2=Paula G. Pazinato |author3=Serita van der Wal |author4=Joachim T. Haug |year=2019 |title=A fossil tanaidacean crustacean from the Middle Jurassic of southern Germany |journal=Palaeodiversity |volume=12 |issue=1 |pages=13–30 |doi=10.18476/pale.v12.a2 |s2cid=146564748 |doi-access=free }}
• A study on the evolutionary history of decapod crustaceans is published by Wolfe et al. (2019).{{Cite journal|author1=Joanna M. Wolfe |author2=Jesse W. Breinholt |author3=Keith A. Crandall|author-link3=Keith A. Crandall |author4=Alan R. Lemmon |author5=Emily Moriarty Lemmon |author6=Laura E. Timm |author7=Mark E. Siddall |author8=Heather D. Bracken-Grissom |year=2019 |title=A phylogenomic framework, evolutionary timeline and genomic resources for comparative studies of decapod crustaceans |journal=Proceedings of the Royal Society B: Biological Sciences |volume=286 |issue=1901 |pages=Article ID 20190079 |doi=10.1098/rspb.2019.0079 |pmid=31014217 |pmc=6501934 }}
• A study on the chemical composition of two specimens of fossilized shrimps from the Cretaceous Romualdo and Ipubi formations (Araripe Basin, Brazil), and on its implications for inferring the course of the processes of fossilization of these crustaceans, is published by Barros et al. (2019).{{Cite journal|author1=Olga Alcântara Barros |author2=João Hermínio Silva |author3=Gilberto Dantas Saraiva |author4=Bartolomeu Cruz Viana |author5=Alexandre Rocha Paschoal |author6=Paulo Tarso Cavalcante Freire |author7=Naiara Cipriano Oliveira |author8=Amauri Jardim Paula |author9=Maria Somália Viana |year=2019 |title=Physicochemical investigation of shrimp fossils from the Romualdo and Ipubi formations (Araripe Basin) |journal=PeerJ |volume=7 |pages=e6323 |doi=10.7717/peerj.6323 |pmid=30783565 |pmc=6378090 |doi-access=free }}
• A study on the Middle Jurassic palaeoenvironment of La Voulte (France), as indicated by data from exceptionally preserved eyes of the polychelidan lobster Voulteryon parvulus and from epibiontic brachiopods associated with V. parvulus, is published by Audo et al. (2019).{{Cite journal|author1=Denis Audo |author2=Ninon Robin |author3=Javier Luque |author4=Michal Krobicki |author5=Joachim T. Haug |author6=Carolin Haug |author7=Clément Jauvion |author8=Sylvain Charbonnier |year=2019 |title=Palaeoecology of Voulteryon parvulus (Eucrustacea, Polychelida) from the Middle Jurassic of La Voulte-sur-Rhône Fossil-Lagerstätte (France) |journal=Scientific Reports |volume=9 |issue=1 |pages=Article number 5332 |doi=10.1038/s41598-019-41834-6 |pmid=30926859 |pmc=6441058 |bibcode=2019NatSR...9.5332A }}
• A study on the anatomy of the holotype specimen of a putative Paleocene shark Platyacrodus unicus is published by Bogan, Agnolin & Ezcurra (2019), who reinterpret this specimen as a carapace of a small retroplumid crab belonging to the genus Costacopluma.{{Cite journal|author1=Sergio Bogan |author2=Federico Agnolin |author3=Martín D. Ezcurra |year=2019 |title=Review of the enigmatic 'shark', Platyacrodus unicus Ameghino, 1935, from the Paleocene of Patagonia, Argentina: a history of palaeontologists, sharks and crabs |journal=Zootaxa |volume=4646 |issue=2 |pages=293–300 |doi=10.11646/zootaxa.4646.2.5 |pmid=31717016 |s2cid=199629925 }}
• An achelatan larval fossil with an intermediate type of morphology, interpreted as the oldest occurrence of an achelatan lobster larva reported so far, is described from the Toarcian Posidonia Shale (Germany) by Haug, Haug & Schweigert (2019).{{Cite journal|author1=Joachim T. Haug |author2=Carolin Haug |author3=Günter Schweigert |year=2019 |title=The oldest "intermetamorphic" larva of an achelatan lobster from the Lower Jurassic Posidonia Shale, South Germany |journal=Acta Palaeontologica Polonica |volume=64 |issue=4 |pages=685–692 |doi=10.4202/app.00627.2019 |doi-access=free }}
• Redescription of the isopod species Palaega sismondai Ristori (1891) is published by Hyžný, Pasini & Garassino (2019), who transfer this species to the genus Bathynomus.{{Cite journal|author1=Matúš Hyžný |author2=Giovanni Pasini |author3=Alessandro Garassino |year=2019 |title=Supergiants in Europe: on the cirolanid isopod Bathynomus A. MILNE EDWARDS, 1879 (Malacostraca, Peracarida) from the Plio-Pleistocene of Italy |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=291 |issue=3 |pages=283–298 |doi=10.1127/njgpa/2019/0802 |s2cid=243239986 }}
• A moult of a giant isopod is described from the early Oligocene Ranzano Formation by Pasini & Garassino (2019), representing the oldest fossil record of the genus Bathynomus from Italy.{{Cite journal|author1=Giovanni Pasini |author2=Alessandro Garassino |year=2019 |title=Bathynomus A. Milne-Edwards, 1879 (Crustacea: Isopoda: Cirolanidae) from the early Oligocene of the Ligure-Piemontese Basin (NW Italy) |journal=Palaeodiversity |volume=12 |issue=1 |pages=95–98 |doi=10.18476/pale.v12.a8 |s2cid=202198206 |doi-access=free }}
• A study on the Late Devonian ostracods from the Yangdi and Nandong sections in South China, and on their responses to the Frasnian-Famennian event, is published by Song, Huang & Gong (2019).{{Cite journal|author1=Junjun Song |author2=Cheng Huang |author3=Yiming Gong |year=2019 |title=Response of Ostracods (Crustacea) to the Devonian F—F event: Evidence from the Yangdi and Nandong sections in Guangxi, South China |journal=Global and Planetary Change |volume=173 |pages=109–120 |doi=10.1016/j.gloplacha.2018.12.015 |bibcode=2019GPC...173..109S |s2cid=133665122 }}
• A diverse earliest Triassic ostracod fauna is reported from the Yangou section in South China by Qiu et al. (2019).{{Cite journal|author1=Xincheng Qiu |author2=Li Tian |author3=Kui Wu |author4=Michael J. Benton |author5=Dongying Sun |author6=Hao Yang |author7=Jinnan Tong |year=2019 |title=Diverse earliest Triassic ostracod fauna of the non-microbialite-bearing shallow marine carbonates of the Yangou section, South China |journal=Lethaia |volume=52 |issue=4 |pages=583–596 |doi=10.1111/let.12332 |hdl=1983/228a76c6-31ad-48ac-a47b-716998e8f1b6 |s2cid=164819804 |url=https://research-information.bris.ac.uk/ws/files/189945210/manuscript_0826_LET_OA_09_18_clean_version.pdf }}
• A revision of ostracods from the Upper Oligocene to Lower Miocene Pirabas Formation (Brazil) is published by Nogueira, Ramos & Hunt (2019).{{cite journal |author1=Anna Andressa Evangelista Nogueira |author2=Maria Inês Feijó Ramos |author3=Gene Hunt |year=2019 |title=Taxonomy of ostracods from the Pirabas Formation (Upper Oligocene to Lower Miocene), Eastern Amazonia (Pará State, Brazil) |journal=Zootaxa |volume=4573 |issue=1 |pages=zootaxa.4573.1.1 |doi=10.11646/zootaxa.4573.1.1 |pmid=31715787 |s2cid=133017934 |url=https://www.researchgate.net/publication/332069852 }}
• A study on changes of diversity of Neogene fossil marine ostracods from Java, Indonesia is published by Shin et al. (2019).{{Cite journal|author1=Caren P. Shin |author2=Moriaki Yasuhara |author3=Hokuto Iwatani |author4=Tomoki Kase |author5=Allan Gil S. Fernando |author6=Hiroki Hayashi |author7=Yukito Kurihara |author8=Hita Pandita |year=2019 |title=Neogene marine ostracod diversity and faunal composition in Java, Indonesia: Indo-Australian Archipelago biodiversity hotspot and the Pliocene diversity jump |journal=Journal of Crustacean Biology |volume=39 |issue=3 |pages=244–252 |doi=10.1093/jcbiol/ruy110 |doi-access=free }}
• A study on deep-sea benthic ostracod assemblages from the southern Sea of Japan covering the last 2 million years, evaluating their responses to the Mid-Brunhes Event, orbital-scale climatic cycles, and fluctuations of the Tsushima Warm Current, is published by Huang et al. (2019).{{Cite journal |author1=Huai-Hsuan May Huang |author2=Moriaki Yasuhara |author3=Hokuto Iwatani |author4=Tatsuhiko Yamaguchi |author5=Katsura Yamada |author6=Briony Mamo |year=2019 |title=Deep-sea ostracod faunal dynamics in a marginal sea: biotic response to oxygen variability and mid-Pleistocene global changes |journal=Paleobiology |volume=45 |issue=1 |pages=85–97 |doi=10.1017/pab.2018.37 |bibcode=2019Pbio...45...85H |s2cid=91447289 }}
• A three-dimensionally preserved specimen of a late growth stage of the phosphatocopid species Cyclotron angelini is described from the Furongian strata of northern Poland by Olempska et al. (2019).{{Cite journal |author1=Ewa Olempska |author2=Andreas Maas |author3=Dieter Waloszek |author4=Mats E. Eriksson |year=2019 |url= http://www.app.pan.pl/archive/published/app64/app005532018.pdf |title=Exceptionally well-preserved Orsten-type phosphatocopid crustaceans from the Cambrian of Poland |journal=Acta Palaeontologica Polonica |volume=64 |issue=1 |pages=19–39 |doi=10.4202/app.00553.2018 |s2cid=134010539 |archive-url=https://web.archive.org/web/20190429175132/http://www.app.pan.pl/archive/published/app64/app005532018.pdf |archive-date=2019-04-29 }}
• A study on the ecology of clam shrimps from the Anjiagou and Hengdaozi beds of the Lower Cretaceous Yixian Formation (China) is published by Hethke et al. (2019).{{Cite journal|author1=Manja Hethke |author2=Franz T. Fürsich |author3=Baoyu Jiang |author4=Bo Wang |author5=Patrick Chellouche |author6=Stephen C. Weeks |year=2019 |title=Ecological stasis in Spinicaudata (Crustacea, Branchiopoda)? Early Cretaceous clam shrimp of the Yixian Formation of north-east China occupied a broader realized ecological niche than extant members of the group |journal=Palaeontology |volume=62 |issue=3 |pages=483–513 |doi=10.1111/pala.12412 |s2cid=197548668 }}
• A study on the oxygen isotope composition of whale barnacle shells from three Pleistocene localities along the eastern Pacific coast, and on their implications for the knowledge of the history of whale migrations, is published by Taylor et al. (2019).{{Cite journal|author1=Larry D. Taylor |author2=Aaron O'Dea |author3=Timothy J. Bralower |author4=Seth Finnegan |year=2019 |title=Isotopes from fossil coronulid barnacle shells record evidence of migration in multiple Pleistocene whale populations |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=116 |issue=15 |pages=7377–7381 |doi=10.1073/pnas.1808759116 |pmid=30910962 |pmc=6462050 |bibcode=2019PNAS..116.7377T |doi-access=free }}
• A study on the internal soft-tissue anatomy of Hesslandona angustata is published by Liu et al. (2019).{{Cite journal|author1=Teng Liu |author2=Baichuan Duan |author3=Huaqiao Zhang |author4=Gong Cheng |author5=Jianbo Liu |author6=Xi-Ping Dong |author7=Dieter Waloszek |author8=Andreas Maas |year=2019 |title=Soft-tissue anatomy of an Orsten-type phosphatocopid crustacean from the Cambrian Furongian of China revealed by synchrotron radiation X-ray tomographic microscopy |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=294 |issue=3 |pages=263–274 |doi=10.1127/njgpa/2019/0858 |s2cid=213824875 }}

{{Main|2019 in insect paleontology}}

• A study on the rates of evolution of trilobites in the Cambrian is published by Paterson, Edgecombe & Lee (2019), who interpret their findings as indicative of Cambrian rather than Precambrian origin of trilobites, and as indicating that the Cambrian explosion had already largely concluded by the time the typical Cambrian fossil record begins (≈521 Ma).{{Cite journal|author1=John R. Paterson |author2=Gregory D. Edgecombe |author3=Michael S. Y. Lee |year=2019 |title=Trilobite evolutionary rates constrain the duration of the Cambrian explosion |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=116 |issue=10 |pages=4394–4399 |doi=10.1073/pnas.1819366116 |pmid=30782836 |pmc=6410820 |bibcode=2019PNAS..116.4394P |doi-access=free }}
• A study on repaired injuries in trilobite specimens from the Cambrian Ruin Wash Lagerstätte (Nevada, United States) is published by Pates & Bicknell (2019), who interpret their findings as indicative of species specific predation on Cambrian trilobites, and of enlarged spines in some trilobite species serving as possible predation deterrents.{{Cite journal|author1=Stephen Pates |author2=Russell D.C. Bicknell |year=2019 |title=Elongated thoracic spines as potential predatory deterrents in olenelline trilobites from the lower Cambrian of Nevada |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=516 |pages=295–306 |doi=10.1016/j.palaeo.2018.12.013 |bibcode=2019PPP...516..295P |s2cid=134371680 |url=http://osf.io/2jr9c/ }}
• A study on the morphology and ontogeny of Changaspis elongata, based on data from specimens from the Lazizhai section of the Balang Formation (Cambrian Stage 4; Guizhou, China), is published by Du et al. (2019).{{Cite journal|author1=Guang-Ying Du |author2=Jin Peng |author3=De-Zhi Wang |author4=Qiu-Jun Wang |author5=Yi-Fan Wang |author6=Hui Zhang |year=2019 |title=Morphology and developmental traits of the trilobite Changaspis elongata from the Cambrian Series 2 of Guizhou, South China |journal=Acta Palaeontologica Polonica |volume=64 |issue=4 |pages=797–813 |doi=10.4202/app.00604.2019 |doi-access=free }}
• A cluster of over 100 juvenile trilobites belonging to the genus Aphelaspis is reported from the Cambrian (Paibian) Conasauga Formation (Georgia, United States) by Schwimmer & Montante (2019).{{Cite journal|author1=David R. Schwimmer |author2=William M. Montante |year=2019 |title=A Cambrian meraspid cluster: evidence of trilobite egg deposition in a nest site |journal=PALAIOS |volume=34 |issue=5 |pages=254–260 |doi=10.2110/palo.2018.102 |bibcode=2019Palai..34..254S |s2cid=181784455 }}
• A study on patterns of occupancy and diversity trajectories in late Cambrian-early Ordovician trilobite communities from the Argentine Cordillera Oriental is published by Serra, Balseiro & Waisfeld (2019).{{Cite journal|author1=Fernanda Serra |author2=Diego Balseiro |author3=Beatriz G. Waisfeld |year=2019 |title=Diversity patterns in upper Cambrian to Lower Ordovician trilobite communities of north-western Argentina |journal=Palaeontology |volume=62 |issue=4 |pages=677–695 |doi=10.1111/pala.12424 |bibcode=2019Palgy..62..677S |s2cid=133945111 }}
• A study on the phylogenetic relationships of members of the family Olenidae is published by Monti & Confalonieri (2019).{{Cite journal|author1=Daniela S. Monti |author2=Viviana A. Confalonieri |year=2019 |title=First cladistic analysis of the trilobite family Olenidae from the Furongian and Ordovician |journal=Lethaia |volume=52 |issue=3 |pages=304–322 |doi=10.1111/let.12313 |s2cid=135043718 }}
• A study on the phylogenetic relationships of members of the olenid subfamily Balnibarbiinae is published by Hopkins (2019).{{Cite journal|author=Melanie J. Hopkins |year=2019 |title=Phylogenetic analysis and revision of the trilobite subfamily Balnibarbiinae (Olenidae) |journal=American Museum Novitates |issue=3928 |pages=1–20 |doi=10.1206/3928.1 |hdl=2246/6938 |s2cid=164469838 |url=https://www.biodiversitylibrary.org/item/266566 }}
• Nine specimens of Symphysurus ebbestadi preserving all key stages of the exoskeleton moulting process are described from the Lower Ordovician Fezouata Formation (Morocco) by Drage et al. (2019).{{Cite journal|author1=Harriet B. Drage |author2=Thijs R.A. Vandenbroucke |author3=Peter Van Roy |author4=Allison C. Daley |year=2019 |title=Sequence of post-moult exoskeleton hardening preserved in a trilobite mass moult assemblage from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco |journal=Acta Palaeontologica Polonica |volume=64 |issue=2 |pages=261–273 |doi=10.4202/app.00582.2018 |doi-access=free |hdl=1854/LU-8635565 |hdl-access=free }}
• A study on clusters of Ampyx priscus from the Ordovician Fezouata Shale of Morocco is published by Vannier et al. (2019), who interpret these clusters as evidence of a collective behaviour rather than a result of passive transportation and accumulation.{{Cite journal|author1=Jean Vannier |author2=Muriel Vidal |author3=Robin Marchant |author4=Khadija El Hariri |author5=Khaoula Kouraiss |author6=Bernard Pittet |author7=Abderrazak El Albani |author8=Arnaud Mazurier |author9=Emmanuel Martin |year=2019 |title=Collective behaviour in 480-million-year-old trilobite arthropods from Morocco |journal=Scientific Reports |volume=9 |issue=1 |pages=Article number 14941 |doi=10.1038/s41598-019-51012-3 |pmid=31624280 |pmc=6797724 |bibcode=2019NatSR...914941V }}
• A study on the phylogenetic relationships of the species and subspecies assigned to the phacopid genus Austerops is published by Oudot et al. (2019).{{Cite journal|author1=Morgane Oudot |author2=Catherine Crônier |author3=Pascal Neige |author4=David Holloway |year=2019 |title=Phylogeny of some Devonian trilobites and consequences for the systematics of Austerops (Phacopidae) |journal=Journal of Systematic Palaeontology |volume=17 |issue=9 |pages=775–790 |doi=10.1080/14772019.2018.1471105 |s2cid=91163530 }}
• A study on the morphological changes in the ontogeny of the Ordovician phacopid trilobite Calyptaulax strasburgensis is published by Jacobs & Carlucci (2019).{{Cite journal|author1=Gabriel S. Jacobs |author2=Jesse R. Carlucci |year=2019 |title=Ontogeny and shape change of the phacopid trilobite Calyptaulax |journal=Journal of Paleontology |volume=93 |issue=6 |pages=1105–1125 |doi=10.1017/jpa.2019.38 |bibcode=2019JPal...93.1105J |s2cid=199098897 }}
• A well-preserved body cluster of 18 specimens of Arctinurus boltoni is described from the Silurian Rochester Shale (New York, United States) by Bicknell, Paterson & Hopkins (2019).{{Cite journal|author1=Russell D.C. Bicknell |author2=John R. Paterson |author3=Melanie J. Hopkins |year=2019 |title=A trilobite cluster from the Silurian Rochester Shale of New York: predation patterns and possible defensive behavior |journal=American Museum Novitates |issue=3937 |pages=1–16 |doi=10.1206/3937.1 |hdl=2246/6959 |s2cid=202401576 |url=https://www.biodiversitylibrary.org/bibliography/162542 }}
• A study on development and evolution of the cephalon and the pygidium in phacopid trilobites is published by Oudot et al. (2019).{{Cite journal|author1=Morgane Oudot |author2=Pascal Neige |author3=Rémi Laffont |author4=Nicolas Navarro |author5=Ahmed Yacine Khaldi |author6=Catherine Crônier |year=2019 |title=Functional integration for enrolment constrains evolutionary variation of phacopid trilobites despite developmental modularity |journal=Palaeontology |volume=62 |issue=5 |pages=805–821 |doi=10.1111/pala.12428 |bibcode=2019Palgy..62..805O |s2cid=181742314 }}
• A study on the internal structures of eyes of trilobites belonging to the genera Asaphus and Archegonus is published by Scholtz, Staude & Dunlop (2019);{{Cite journal|author1=Gerhard Scholtz |author2=Andreas Staude |author3=Jason A. Dunlop |year=2019 |title=Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities |journal=Nature Communications |volume=10 |issue=1 |pages=Article number 2503 |doi=10.1038/s41467-019-10459-8 |pmid=31175282 |pmc=6555793 |bibcode=2019NatCo..10.2503S }} the study is subsequently criticized by Schoenemann & Clarkson (2021).{{Cite journal|author1=Brigitte Schoenemann |author2=Euan N. K. Clarkson |year=2021 |title=Points of view in understanding trilobite eyes |journal=Nature Communications |volume=12 |issue=1 |pages=Article number 2081 |doi=10.1038/s41467-021-22227-8 |pmid=33828091 |pmc=8027602 |bibcode=2021NatCo..12.2081S }}{{Cite journal|author1=Gerhard Scholtz |author2=Andreas Staude |author3=Jason A. Dunlop |year=2021 |title=Reply to "Points of view in understanding trilobite eyes" |journal=Nature Communications |volume=12 |issue=1 |pages=Article number 2084 |doi=10.1038/s41467-021-22228-7 |pmid=33828090 |pmc=8027826 |bibcode=2021NatCo..12.2084S }}
• A study on the variability of trilobite moulting behaviour is published by Drage (2019).{{cite journal |author=Harriet B. Drage |year=2019 |title=Quantifying intra- and interspecific variability in trilobite moulting behaviour across the Palaeozoic |journal=Palaeontologia Electronica |volume=22 |issue=2 |pages=Article number 22.2.34 |doi=10.26879/940 |doi-access=free }}