Sunday, October 10, 2021

Compact Thescelosaurus Year Six

The time has come again for the annual review of The Compact Thescelosaurus. This year's new page is on aetosaurs and their close relatives, with the classification diagram page updated. (Don't forget, Wednesday the 13th is also National Fossil Day!)

Aetosaur Desmatosuchus spurensis is one of the subjects of the NPS Prehistoric Life Coloring Book. Coincidentally, an aetosaur also featured in the 2014 National Fossil Day artwork.

There aren't a lot of aetosaurs, so this sheet didn't take as much struggle as some of the others. Key references were Desojo et al. (2013) and Parker (2016). The Aetosauriformes part was added after Parker et al. (2021), on the grounds that it seemed like a reasonable thing to add.

For the rest of the update: Since last year's post on October 11, 2020, I've made 97 entries to the Update sheet, including a late spurt over the past few weeks. These included 55 new taxa, 4 existing species moved to new genera, 2 dubious species reinstated, and Ubirajara jubatus, which I'm holding back for now because the publication in press was withdrawn. As usual, most of the new additions come from Cretaceous rocks. There was 1 new taxa from the Middle Triassic, 2 from the Upper Triassic, 2 from the Lower Jurassic, 1 from the Middle Jurassic, 2 from rocks of the Middle–Upper Jurassic, 6 from the Upper Jurassic, 13 from the Lower Cretaceous, and 28 from the Upper Cretaceous. (I also updated the geologic time scale after "Geologic Time Scale 2020", although this is feeling a bit awkward because the International Commission on Stratigraphy isn't using the dates.)

Geographically, South America took over from Asia as the most productive continental landmass, with 16 new taxa versus 14. Europe took third with a late push to 10, followed by North America with 9, Africa with 4, and Australia with 2. Argentina and China tied with 9 new taxa for the most productive countries. Brazil and the United States tied for third with 5, followed by a tie between Morocco and the United Kingdom with 4, a tie between Mexico and Spain with 3, and a tie between Australia and Uzbekistan with 2. 9 countries each contributed 1 new taxon: Canada, Chile, France, Japan, Mongolia, Portugal, Russia, Tajikistan, and Uruguay.

In taxonomic terms, we had:

1 new choristodere species:
Mengshanosaurus minimus

5 new ichthyosaur species:
Catutosaurus gaspariniae
Jabalisaurus meztli
Parrassaurus yacahuitztli
Sumpalla argentina
Thalassodraco etchesi
Another good year for ichthyosaurs.

3 new mosasaur species:
Ectenosaurus everhartorum
Pluridens serpentis
Xenodens calminechari

3 new plesiosaur species:
Fluvionectes sloanae
Jucha squalea
Plesiopharos moelensis

7 new pterosaur species:
Javelinadactylus sagebieli
Kariridraco dianae
Kunpengopterus antipollicatus
Otogopterus haoae
Sinomacrops bondei
Tacuadactylus luciae
Thapunngaka shawi

1 new basal sauropterygian species:
Brevicaudosaurus jiyangshanensis

14 new theropod species (classic dinosaurs only)
Ceratosuchops inferodios
Erythovenator jacuiensis
Kansaignathus sogdianus
Kurupi itaata
Llukalkan allocranianus
Niebla antiqua
Papiliovenator neimengguensis
Pendraig milnerae
Ripariovenator milnerae
Shri devi
Spectrovenator ragei
Tamarro insperatus
Ulughbegsaurus uzbekistanensis
Ypupiara lopai
An odd mix; almost all abelisaurs, spinosaurs, or little theropods, almost all Cretaceous, and a definite South American flavor.

11 new sauropod species:
Arackar licanantay
Australotitan cooperensis
Bagualia alba
Bravasaurus arrierosorum
Dzharatitanis kingi
Garrigatitan meridionalis
Hamititan xinjiangensis
Menucocelsior arriagadai
Ninjatitan zapatai
Punatitan coughlini
Silutitan sinensis
Almost a titanosaur sweep: all but Bagualia alba and Silutitan sinensis were either described as titanosaurs or were moved to that group.

1 new thyreophoran species:
Spicomellus afer

2 new ceratopsian species:
Menefeeceratops sealeyi
Sierraceratops turneri

7 new ornithopod species:
Ajnabia odysseus
Fylax thyrakolasus
Napiasaurus guangxiensis
Ornatops incantatus
Portellsaurus sosbaynati
Tlatolophus galorum
Yamatosaurus izanagii
Basically all hadrosaurs or close relatives, including that rarest of birds, a new lambeosaurine with actual crest preserved (thank you very much, Tlatolophus!).

4 species were transferred to new genera:
Aeolosaurus maximus to Arrudatitan
Dendrorhynchoides mutoudengensis to Luopterus
"Morosaurus" agilis to Smitanosaurus
"Troodon" bexelli to Sinocephale

2 dubious species were reinstated as housekeeping:
Polacanthoides ponderosus
"Polacanthus" becklessi
In related work, Horshamosaurus was busted as dubious and reverted to "Polacanthus" rudgwickensis, and "Hylaeosaurus" oweni was briefly reinstated until it was pointed out that it was a junior objective synonym of H. armatus.

Finally, in work that did not add or subtract a species, Parrosaurus was revalidated for "Neosaurus" missouriensis (aka Hypsibema missouriensis).


Desojo, J. B., A. B. Heckert, J. W. Martz, W. G. Parker, R. R. Schoch, B. J. Small, and T. Sulej. 2013. Aetosauria: a clade of armoured pseudosuchians from the Upper Triassic continental beds. Pages 203–239 in Anatomy, phylogeny, and palaeobiology of early archosaurs and their kin. Geological Society, London, United Kingdom. Special Publication 379.

Parker, W. G. 2016. Revised phylogenetic analysis of the Aetosauria (Archosauria: Pseudosuchia); assessing the effects of incongruent morphological character sets. PeerJ 4:e1583. doi:10.7717/peerj.1583.

Parker, W. G., S. J. Nesbitt, R. B. Irmis, J. W. Martz, A. D. Marsh, M. A. Brown, M. R. Stocker, and S. Werning. 2021. Osteology and relationships of Revueltosaurus callenderi (Archosauria: Suchia) from the Upper Triassic (Norian) Chinle Formation of Petrified Forest National Park, Arizona, United States. The Anatomical Record. doi:10.1002/ar.24757.

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