Natovenator

{{Short description|Genus of dromaeosaurid dinosaurs from the Late Cretaceous}}

{{Speciesbox

| fossil_range = Maastrichtian, {{Fossil range|72|71}}

| image = Natovenator skeletal (holotype).png

| image_caption = Skeletal reconstruction, based on the holotype

| parent_authority = Lee et al., 2022

| display_parents = 2

| taxon = Natovenator polydontus

| authority = Lee et al., 2022

}}

Natovenator is a genus of halszkaraptorine dromaeosaurid dinosaur from the Late Cretaceous Barun Goyot Formation of Mongolia. The genus is known from a single species, N. polydontus. Natovenator is crucial to the understanding of halszkaraptorines due to it providing more support for the semi-aquatic lifestyle that has been proposed for this clade.{{cite journal|last1=Lee|first1=S.|last2=Lee|first2=Y.-N.|last3=Currie|first3=P. J.|last4=Sissons|first4=R.|last5=Park|first5=J.-Y.|last6=Kim|first6=S.-H.|last7=Barsbold|first7=R.|last8=Tsogtbaatar|first8=K.|date=2022|title=A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming|journal=Communications Biology|volume=5|number=1185|page=1185 |doi=10.1038/s42003-022-04119-9|doi-access=free|pmid=36456823 |issn=2399-3642|pmc=9715538}} This discovery is important as the semi-aquatic lifestyles of halszkaraptorines (mainly Halszkaraptor) was contested in early 2022.{{cite journal |last1=Fabbri |first1=Matteo |last2=Navalón |first2=Guillermo |last3=Benson |first3=Roger B. J. |last4=Pol |first4=Diego |last5=O’Connor |first5=Jingmai |last6=Bhullar |first6=Bhart-Anjan S. |last7=Erickson |first7=Gregory M. |last8=Norell |first8=Mark A. |last9=Orkney |first9=Andrew |last10=Lamanna |first10=Matthew C. |last11=Zouhri |first11=Samir |last12=Becker |first12=Justine |last13=Emke |first13=Amanda |last14=Dal Sasso |first14=Cristiano |last15=Bindellini |first15=Gabriele |date=March 23, 2022 |title=Subaqueous foraging among carnivorous dinosaurs |journal=Nature |volume=603 |issue=7903 |pages=852–857 |bibcode=2022Natur.603..852F |doi=10.1038/s41586-022-04528-0 |pmid=35322229 |last16=Maganuco |first16=Simone |last17=Auditore |first17=Marco |last18=Ibrahim |first18=Nizar |s2cid=247630374|url=https://ora.ox.ac.uk/objects/uuid:264b7ca2-1190-4b76-ab93-074cedf897e1 }}

Discovery and naming

File:Natovenator holotype block.png

The Natovenator holotype specimen, MPC-D 102/114, was found in sediments of the Barun Goyot Formation of Omnogovi Province, Mongolia. It consists of a mostly articulated skeleton with a nearly complete skull.

The specimen was first mentioned in a 2019 abstract.{{Cite journal |last1=Lee|first1=S.|last2=Lee|first2=Y.-N.|last3=Currie|first3=P. J.|last4=Sissons|first4=R.|last5=Park|first5=J.-Y.|last6=Kim|first6=S.-H.|last7=Barsbold|first7=R.|last8=Tsogtbaatar |date=October 2019 |title=A new halszkaraptirine from the Baruungoyor Formation of Mongolia: Preliminary description and phylogenetic analysis |url=http://vertpaleo.org/Annual-Meeting/Annual-Meeting-Home/SVP-Program-book-v5_w-covers.aspx#page=168 |url-status=dead |journal=Society of Vertebrate Paleontology Abstracts of Papers, 79th Annual Meeting |pages=167 |archive-url=https://web.archive.org/web/20201215024254/http://vertpaleo.org/Annual-Meeting/Annual-Meeting-Home/SVP-Program-book-v5_w-covers.aspx#page=168 |archive-date=2020-12-15 |access-date=2024-04-02}} In 2022, Natovenator polydontus was described as a new genus and species of halszkaraptorine theropod dinosaurs by Sungjin Lee, Yuong-Nam Lee, Philip J. Currie, Robin Sissons, Jin-Young Park, Su-Hwan Kim, Rinchen Barsbold, and Khishigjav Tsogtbaatar based on these remains. The generic name, "Natovenator", is derived from the Latin words "nato", meaning "to swim", and "venator", meaning "hunter", in reference to its piscivorous diet and possible swimming behaviour. The specific name, "polydontus", is derived from the Greek words "polys", meaning "many", and "odous", meaning "tooth".

Description

File:Natovenator holotype skull.png

Natovenator was a very small theropod, comparable in appearance to extant waterfowl, like other members of the Halszkaraptorinae. In the third edition of The Princeton Field Guide to Dinosaurs, Gregory S. Paul stated its length at {{convert|0.7|m|ft}} and weight at {{convert|0.3|kg|lb}}.{{Cite book |last=Paul |first=Gregory S. |title=The Princeton Field Guide to Dinosaurs |date=2024 |publisher=Princeton University Press |isbn=978-0-691-23157-0 |edition=3rd |series=Nature |location=Princeton and Oxford}} Natovenator is different from other halszkaraptorines due to features such as a wide groove delimited by a pair of ridges on the anterodorsal surface of the premaxilla, a premaxilla with an elongated internarial process that overlies nasal and extends posterior to the external naris, 13 premaxillary teeth with large and incisiviform crowns, the absence of pleurocoels in cervical vertebrae, and an hourglass-shaped metacarpal II, among other features. The parapophyses in its vertebrae are similar to the extinct Hesperornithiformes, which were toothed diving birds.

Classification

File:Natovenator holotype postcrania.png

In their phylogenetic analyses, Lee et al. (2022) recovered Natovenator as a derived member of the Halszkaraptorinae, with Halszkaraptor being the most basal member of the group. The cladogram below displays the results of their phylogenetic analyses.

{{clade| style=font-size:100%; line-height:100%;

|label1=Dromaeosauridae

|1={{clade

|label1=Halszkaraptorinae

|1={{clade

|1=Halszkaraptor

80px

|2={{clade

|1=Natovenator

|2=Hulsanpes

60px

|3=Mahakala

60px

}} }}

|2={{clade

|1=Unenlagiinae

80px

|2={{clade

|1=Pyroraptor

80px

|2={{clade

|1=Zhenyuanlong 60px

|2=Microraptoria

80px

|3={{clade

|1=Bambiraptor 80px

|2=Eudromaeosauria

80px

}} }} }} }} }} }}

Paleobiology

=Aquatic habits=

File:Natovenator hunting fish.png of Natovenator]]

In 2022, Lee and colleagues regarded Natovenator as an efficient swimming dromaeosaurid with a semiaquatic lifestyle. The multiple convergences with other aquatic vertebrates include an elongated snout with numerous teeth, delayed replacement pattern of premaxillary teeth, a complex neurovascular system on the snout tip, elongated neck and vertebral zygapophyses, and a retracted, long naris (nostril opening). The team indicated that the delayed pattern of the premaxillary dentition could have allowed it to keep providing enlarged teeth in Natovenator, in a similar way to sauropterygians. Similar to many modern-day diving birds, the neck of Natovenator was rather long, likely useful in catching/snatching prey. Most notably, its dorsal rib cage had posteriorly-oriented ribs, providing a streamlined shape that is also known in efficient diving birds, mosasaurs, choristoderes, and spinosaurids. Even though the exact aquatic locomotion of Natovenator is unknown, Lee and colleagues suggested that its forelimbs acted as flippers for propulsion when swimming.

Paleoenvironment

The Barun Goyot Formation is regarded as Late Cretaceous in age (Upper Campanian) based on sediments and fossil content. This formation is mostly characterized by red beds, mostly light-coloured sands (yellowish, grey-brown, and to a lesser extent reddish) that are well-cemented. Sandy claystones (often red-coloured), siltstones, conglomerates, and large-scale trough cross-stratification in sands are also common across the unit. In addition, structureless, medium-grained, fine-grained and very fine-grained sandstones predominate in sediments of the Barun Goyot Formation. Overall geology of the formation indicates that sediments were deposited under relatively arid to semiarid climates in alluvial plain (flat land consisting of sediments deposited by highland rivers), lacustrine, and aeolian paleoenvironments, with addition of other short-lived water bodies.{{cite journal|last1=Gradziński|first1=R.|last2=Jerzykiewicz|first2=T.|date=1974|title=Sedimentation of the Barun Goyot Formation|journal=Palaeontologia Polonica|volume=30|pages=111−146|url=http://www.palaeontologia.pan.pl/Archive/1974_30_111-146_34-42.pdf}}{{cite journal|last1=Gradziński|first1=R.|last2=Jaworowska|first2=Z. K.|last3=Maryańska|first3=T.|date=1977|title=Upper Cretaceous Djadokhta, Barun Goyot and Nemegt formations of Mongolia, including remarks on previous subdivisions|journal=Acta Geologica Polonica|volume=27|number=3|pages=281–326|url=https://geojournals.pgi.gov.pl/agp/article/view/9555/8104}}{{cite journal|last1=Eberth|first1=D. A.|date=2018|title=Stratigraphy and paleoenvironmental evolution of the dinosaur-rich Baruungoyot-Nemegt succession (Upper Cretaceous), Nemegt Basin, southern Mongolia|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=494|pages=29–50|bibcode=2018PPP...494...29E|doi=10.1016/j.palaeo.2017.11.018}}

The Barun Goyot Formation was also home to many other vertebrates, including the ankylosaurids Saichania, Tarchia and Zaraapelta;{{cite journal|last1=Arbour|first1=V. M.|last2=Currie|first2=P. J.|last3=Badamgarav|first3=D.|date=2014|title=The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia|journal=Zoological Journal of the Linnean Society|volume=172|issue=3|pages=631−652|doi=10.1111/zoj.12185|doi-access=free}}{{cite journal|last1=Park|first1=J.-Y.|last2=Lee|first2=Y. N.|last3=Currie|first3=P. J.|last4=Ryan|first4=M. J.|last5=Bell|first5=P.|last6=Sissons|first6=R.|last7=Koppelhus|first7=E. B.|last8=Barsbold|first8=R.|last9=Lee|first9=S.|last10=Kim|first10=S.-H.|date=2021|title=A new ankylosaurid skeleton from the Upper Cretaceous Baruungoyot Formation of Mongolia: its implications for ankylosaurid postcranial evolution|journal=Scientific Reports|volume=11|number=4101|page=4101|doi=10.1038/s41598-021-83568-4|doi-access=free|pmc=7973727|pmid=33737515}} alvarezsaurids Khulsanurus, Ondogurvel, and Parvicursor;{{cite journal|last1=Averianov|first1=A. O.|last2=Lopatin|first2=A. V.|date=2022|title=A new alvarezsaurid theropod dinosaur from the Upper Cretaceous of Gobi Desert, Mongolia|journal=Cretaceous Research|volume=134|doi=10.1016/j.cretres.2022.105168|bibcode=2022CrRes.13505168A }}{{cite journal|last1=Averianov|first1=A. O.|last2=Lopatin|first2=A. V.|date=2022|title=A re-appraisal of Parvicursor remotus from the Late Cretaceous of Mongolia: implications for the phylogeny and taxonomy of alvarezsaurid theropod dinosaurs |journal=Journal of Systematic Palaeontology|volume=19 |issue=16 |pages=1097–1128 |doi=10.1080/14772019.2021.2013965 |s2cid=247222017 }} birds Gobipipus, Gobipteryx and Hollanda;{{cite journal|last1=Bell|first1=A. K.|last2=Chiappe|first2=L. M.|last3=Erickson|first3=G. M.|last4=Suzuki|first4=S.|last5=Watabe|first5=M.|last6=Barsbold|first6=R.|last7=Tsogtbaatar|first7=K.|date=2010|title=Description and ecologic analysis of Hollanda luceria, a Late Cretaceous bird from the Gobi Desert (Mongolia)|journal=Cretaceous Research|volume=31|issue=1|pages=16−26|doi=10.1016/j.cretres.2009.09.001|bibcode=2010CrRes..31...16B |url=https://www.researchgate.net/publication/229349737}} dromaeosaurids Kuru and Shri;{{cite journal|last1=Turner|first1=A. H.|last2=Montanari|first2=S.|last3=Norell|first3=M. A.|date=2021|title=A New Dromaeosaurid from the Late Cretaceous Khulsan Locality of Mongolia|journal=American Museum Novitates|number=3965|pages=1–48|doi=10.1206/3965.1|hdl=2246/7251|hdl-access=free|s2cid=231597229|issn=0003-0082|url=http://digitallibrary.amnh.org/bitstream/handle/2246/7251/N3965.pdf?sequence=1&isAllowed=y}}{{cite journal|last1=Napoli|first1=J. G.|last2=Ruebenstahl|first2=A. A.|last3=Bhullar|first3=B.-A. S.|last4=Turner|first4=A. H.|last5=Norell|first5=M. A.|date=2021|title=A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia|journal=American Museum Novitates|number=3982|pages=1–47|doi=10.1206/3982.1|issn=0003-0082|hdl=2246/7286|hdl-access=free|url=https://digitallibrary.amnh.org/bitstream/handle/2246/7286/3982.pdf?sequence=1&isAllowed=y}} fellow halszkaraptorine Hulsanpes;{{cite journal|last1=Cau|first1=A.|last2=Madzia|first2=D.|date=2018|title=Redescription and affinities of Hulsanpes perlei (Dinosauria, Theropoda) from the Upper Cretaceous of Mongolia|journal=PeerJ|volume=6|pages=e4868|doi=10.7717/peerj.4868|doi-access=free|pmc=5978397|pmid=29868277}} protoceratopsids Bagaceratops and Breviceratops;{{cite journal|last1=Czepiński|first1=Ł.|date=2019|title=Ontogeny and variation of a protoceratopsid dinosaur Bagaceratops rozhdestvenskyi from the Late Cretaceous of the Gobi Desert|journal=Historical Biology|volume=32 |issue=10 |pages=1394–1421|doi=10.1080/08912963.2019.1593404|bibcode=2020HBio...32.1394C |s2cid=132780322 |url=http://dinosaurmailinglist.cmnh.org/2019Apr/pdfzmfpMk1aO4.pdf}} pachycephalosaurid Tylocephale;{{cite journal|last1=Sullivan|first1=R. M.|date=2006|title=A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia)|journal=New Mexico Museum of Natural History and Science Bulletin|issue=35|pages=347–365|url=https://www.researchgate.net/publication/240625747}} oviraptorids Conchoraptor, Heyuannia and Nemegtomaia;{{cite journal|last1=Fanti|first1=F.|last2=Currie|first2=P. J.|last3=Badamgarav|first3=D.|last4=Lalueza-Fox|first4=C.|date=2012|title=New specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia|journal=PLOS ONE|volume=7|issue=2|pages=e31330|bibcode=2012PLoSO...731330F|doi=10.1371/journal.pone.0031330|doi-access=free|pmc=3275628|pmid=22347465}}{{cite journal|last1=Funston|first1=G. F.|last2=Mendonca|first2=S. E.|last3=Currie|first3=P. J.|last4=Barsbold|first4=R.|last5=Barsbold|first5=R.|date=2018|title=Oviraptorosaur anatomy, diversity and ecology in the Nemegt Basin|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=494|pages=101–120|doi=10.1016/j.palaeo.2017.10.023|bibcode=2018PPP...494..101F|url=https://drive.google.com/file/d/1ydVF-p_qKu2NIL7fKb3zJydai_eurXts/view|url-access=subscription}} and the large sauropod Quaesitosaurus.{{cite journal|last1=Kurzanov|first1=S. M.|last2=Bannikov|first2=A. F.|date=1983|title=A new sauropod from the Upper Cretaceous of Mongolia|journal=Paleontological Journal|volume=2|pages=90−96|url=https://moam.info/a-new-sauropod-from-the-upper-cretaceous-of-mongolia_5b764105097c4785168b45fe.html}}