Sunday, October 8, 2017

Compact Thescelosaurus Year Two

It's that time of year again, with National Fossil Day just around the corner (Wednesday the 11th) and the anniversary of the original Thescelosaurus just behind us (Saturday the 7th). The Compact Thescelosaurus is up for its second birthday, and this time I have something slightly more ambitious to add than choristoderes, as nice as they are (you may be unsurprised to learn that none of the entries in the "Updates" sheet were specifically for choristoderes). This year the pterosaurs join on their own sheet. The rules of the sheet are the same as for the other taxonomic sheets, except there's one more classification column. As it is, the classification columns are still kind of a kludge, but I haven't figured out a better way to handle the various nested clades.

Had to lie on my back on the Science Museum lobby floor to get that.

A couple of comments:

Pterosaur classification lacks consensus. (Ha.) In the face of a lot of mutual incompatibilities, I winged it, no pun intended. I leaned heavily on Andres et al. (2014), with  Rodrigues and Kellner (2013) for Ornithocheirus and friends and some Vidovic and Martill (2017) in the ctenochasmatoids. I am fully confident that I have produced a hybrid which will please no one. C'est la vie.

Pterosaur diversity is heavily weighted to just a few units. In roughly chronological order, the most important are:
  • The Tiaojishan Formation (early Late Jurassic) of China
  • The Solnhofen Formation (late Late Jurassic) and some related units in Germany
  • The Jiufotang/Yixian formations (middle Early Cretaceous) of China
  • The Santana Group (late Early Cretaceous) of Brazil
  • The Cambridge Greensand of the UK (reworked late Early Cretaceous)
There are also a fair number of pterosaurs from the Morrison and Tendaguru formations, almost invariably based on poor material, and the Niobrara Formation has yielded numerous pterosaur specimens, but of only a few species. Of the 256 [255; "Ornithocheirus" hilsensis in two places at once] entries, 145 fall under these 8 groups, or close to 3/5ths. (Note that in a couple of instances, faces with diminishing returns, I lumped dubious and forgotten species into "wastebaskets". This happened to some leftover Niobrara and Solnhofen species; if I'd broken them out, it would have been 155 out of 265.)

Now we come to the review of the previous year. There have been 83 entries on the Updates sheet since October 16, 2016, our last review. The breakdown of the updates is as follows:

42 names were introduced, with 37 new species, 4 reinstatements, and Beipiaognathus jii (withheld at the last update as a potential chimera, accepted on review as dinosaurian). This total is about the same as last year's 41. The temporal diversity is greater, with 4 Late Triassic, 1 Early Jurassic, 1 Middle Jurassic, 3 Late Jurassic, 13 Early Cretaceous, and 15 Late Cretaceous new taxa. Geographically, it's the same top 3 this year, although the order is different (10 for China, 6 for Argentina, and 4 for the United States). This is followed by a three-way tie for fourth (Brazil, Canada, and Spain, 3 each). Other contributors include Australia, the Czech Republic, France, Mexico, Mongolia, Morocco, Russia, and Tanzania (1 each). The taxonomic breakdown is as follows:

1 new dinosauromorph species:
Ixalerpeton polesinensis

15 new theropod species:
Aepyornithomimus tugrikinensis
Albertavenator curriei
Beibeilong sinensis
Chenanisaurus barbaricus
Corythoraptor jacobsi
Daliansaurus liaoningensis
Daspletosaurus horneri
Jianianhualong tengi
Latenivenatrix mcmasterae
Liaoningovenator curriei
Lucianovenator bonoi
Powellvenator podocitus
Serikornis sungei
Tongtianlong limosus
Zhongjianosaurus yangi
This batch leans heavily on maniraptorans (10 out of 15), the exceptions being Aepyornithomimus tugrikinensis (ornithomimid), Chenanisaurus barbaricus (abelisaurid), Daspletosaurus horner (tyrannosaurid), and two Late Triassic coelophysoids from Argentina (Lucianovenator bonoi and Powellvenator podocitus). The non-maniraptors are equaled by an unusually good year for troodontids (Albertavenator curriei, Daliansaurus liaoningensis, Jianianhualong tengi, Latenivenatrix mcmasterae, and Liaoningovenator curriei).

2 new "prosauropod" species:
Buriolestes schultzi
Xingxiulong chengi
Buriolestes schultzi is pretty close to the base of Sauropodomorpha, while Xingxiulong chengi is much closer to Sauropoda.

11 new sauropod species:
Choconsaurus baileywillisi
Europatitan eastwoodi
Galeamopus pabsti
Moabosaurus utahensis
Patagotitan mayorum
Savannasaurus elliottorum
Shingopana sungwensis
Soriatitan golmayensis
Tengrisaurus starkovi
Triunfosaurus leonardii
Vouivria damparisensis
Sauropods staged a significant rally, more than doubling last year. As usual, the titanosaurians are the winners. The only non-titanosaurs are Europatitan eastwoodi (for certain values of Titanosauria), Galeamopus pabsti, Moabosaurus utahensis, and two brachiosaurids (Soriatitan golmayensis and Vouivria damparisensis).

3 new thyreophoran species:
Borealopelta markmitchelli
Isaberrysaura mollensis
Zuul crurivastator
I'm tentatively accepting Isaberrysaura as a basal stegosaurian. The thyreophorans made their shots count this year! Along with Patagotitan and Serikornis, these three are among the most memorable newcomers of the past 12 months.

1 new ceratopsian species:
Yehuecauhceratops mudei
What, no basal ceratopsians?

4 new ornithopod species:
Bonapartesaurus rionegrensis
Burianosaurus augustai
Laiyangosaurus youngi
Magnamanus soriaensis
This has been a slow year for ornithopods, with two hadrosaurids (Bonapartesaurus rionegrensis and Laiyangosaurus youngi) and a more basal iguanodont (Magnamanus soriaensis), and a species that is an iguanodont or a more basal ornithopod depending on your tree and definitions (Burianosaurus augustai).

4 reinstatements:
Polyodontosaurus grandis
Stenonychosaurus inequalis (genus reinstatement; species had been accepted before)
Tanius chingkankouensis
"Tanius" laiyangensis
A mixed bag, with two troodontids from the disintegration of Troodon and housekeeping in Tanius.

On the other side of the ledger, there were 2 removals, 1 genus sunk, 1 old species moved to a new genus and then lost almost immediately, and 1 genus/species accepted as a synonym on arrival:

2 deletions:
"Omosaurus leedsi" (nomen nudum)
Razanandrongobe sakalavae (non-dinosaurian)

1 sinking:
Ugrunaaluk into Edmontosaurus

1 "death" by misadventure:
"Laelaps" macropus moved to new genus Teihivenator and then killed almost immediately

1 immediate sinking:
Shuangbaisaurus anlongbaoensis into Sinosaurus triassicus

There was also one lateral move of an existing species into a new genus:
"Stegoceras" brevis to Foraminacephale brevis

The other 35 entries in the updates are various moves, reorganizations, and updates to formations, national subdivisions, and higher-level nomenclature.


Andres, B., J. Clark, and X. Xu. 2014. The earliest pterodactyloid and the origin of the group. Current Biology 24(9):1011–1016.

Rodrigues, T., and A. W. A. Kellner. 2013. Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England. ZooKeys 308:1–112.

Vidovic, S. U., and D. M. Martill. 2017. The taxonomy and phylogeny of Diopecephalus kochi (Wagner, 1837) and ‘Germanodactylus rhamphastinus’ (Wagner, 1851). Geological Society of London Special Publications 455. doi:10.1144/SP455.12.


  1. Happy birthday Thescelosaurus! I was extremely excited when I saw this. You have done an amazing thing.

    1. I also just noticed a discrepancy, Ornithocheirus hilsensis is listed on both the Dinosauria and Pterosauria sheets.

    2. Huh, whaddya know? And the funny thing is, there are two different formations listed (Obernkirchen Sandstein for the dinosaur, per the Theropod Database, versus Elligserbrink Shale Formation for the pterosaur, per the Paleobiology Database).

    3. I decided I wanted the dinosaur listing and not the pterosaur listing. Thank you!