Saturday, September 5, 2015

Where are they now: 1980s dinosaur rumors, ornithischians

We now reach the final section, the part dealing with ornithischians (links to theropods and sauropodomorphs). The ornithischian portion of Glut (1982)'s Addendum II is a real mixed bag. It's not just because people seem to forget about ornithischians, especially when the ornithischians come without bearing horns or plates. There's some really scrappy stuff listed and some really vague entries, as well as two genera that had been named and had entries in the rest of the book, and a third that had been named but hadn't made the book.

Ornithischians:
Ornithopods:
The Coober Pedy ornithopod and Lightning Ridge hypsilophodont: The former, at least, is indeterminate. The latter could be any of several named and unnamed hypsils, in the absence of more context. Both are examples of the singular Australian propensity for pieces-parts of hypsils. You may have also noticed that there are a lot of Australian entries in Addendum II, many of which remain unresolved. Part of this is due to the scrappy Australian fossil record for classic dinosaurs, leading to extra publicity for what has been found and also making it difficult to determine what exactly is represented by the isolated remains. In addition, Australia's dinosaurs are often representatives of Gondwanan lineages. In 1982 Abelisauridae hadn't even been named, and titanosaurs were basically Cretaceous sauropods with narrow teeth.

The Nova Scotia fabrosaur: this is one of the Triassic "dinosaurs" killed off in the mid '00s via better knowledge of Triassic archosaurs (Irmis et al. 2007).

A flat-headed hadrosaur from Baishin-Tsav: There are actually two entries in Addendum II that appear to be related. This particular entry is doubtless for the same animal that is briefly discussed and illustrated in Norman and Sues (2000). It was to have been described in Norman's series on Asian ornithopods, after a redescription of Probactrosaurus, but this publication has not come to pass. Now, here's where the overlap comes in. Later in Addendum II is an entry for "Gadolosaurus", an informal name (actually a Japanese translation of the Cyrillic word for "hadrosaur") for a juvenile iguanodontian skeleton. Like the Baishin-Tsav hadrosaur, this material was collected from Mongolia by the Soviet–Mongolian expeditions of the '70s. I strongly suspect that "Gadolosaurus" is an example of the flat-headed hadrosaur from Baishin-Tsav. The information published about the two animals appears to be congruent, and photos of the skeleton of "Gadolosaurus" show no particular differences with the juvenile skull illustrated by Norman and Sues (2000). (Note, though, that per Glut 1997 the "gadolosaur" on traveling exhibition is apparently wearing a lot of plaster.) For reasons unclear to me, these fossils have sometimes been assigned to Arstanosaurus, one of the least impressive dinosaurs named since 1980.

An iguanodont from Mongolia with a large snout, formerly assigned to Iguanodon orientalis: this was named Altirhinus kurzanovi in 1998, and I. orientalis has been more or less abandoned.

A hadrosaur from Chubut, once thought to be Paleocene in age: the details appear to describe Secernosaurus koerneri, the only problems being it had been named in 1979 and is included earlier in Glut (1982). This may simply be an entry that should have been edited out, or perhaps there was some confusion with what would named Kritosaurus australis in 1984 (and assigned to Secernosaurus in 2010).

"Hypsilophodont-type dinosaurs" from Uruguay, Switzerland, and New South Wales: in the absence of any additional information, there's not much to say.

An iguanodont apparently from Mysore, India: this report is unconfirmed.

The Fruita fabrosaurid: we met this critter as the "Fruita coelurosaur". It is, of course, Fruitadens.

Thecodontosaurus gibbidens: like the "Nova Scotia fabrosaur" above, Thecodontosaurus gibbidens is non-dinosaurian. This was not realized before it was renamed Galtonia in 1994. It is now regarded as a revueltosaur (Irmis et al. 2007). Revueltosaurs are difficult to describe offhandedly, but they occupied a slice of the wing of archosaurs that includes crocodiles and their relatives. They were small, armored, big-headed, and had upright limbs.

A lambeosaurine from the Nemegt known from pelvic and hindlimb bones: this was named Barsboldia sicinskii in 1981, and must have just missed the book. Incidentally, it's now thought to have been a saurolophine instead of a lambeosaurine.

"Gadolosaurus": see above, under the Baishin-Tsav hadrosaur.

Stegosaurs:
Four scutes from Rodbourne, England and a tail spine from Swindon, England [two separate entries]: with thirty years' hindsight, I'm not sure what was so special about these to necessitate their inclusion, or why the scutes were listed with the stegosaurs when they were compared to scutes of Hylaeosaurus. The tail spine was compared to those of Kentrosaurus.

The "questionable ankylosaur" ilium from the Cleveland-Lloyd Quarry: we have heard nary a peep from this specimen. It ended up in the stegosaur section here because there was some question about its identity, ankylosaurs not yet having been described from the Morrison. We now have Gargoyleosaurus and Mymoorapelta, removing that obstacle. Recent sources like Foster (2003) have kept an unspecified "Ankylosauria" in their faunal lists for the quarry, so it's still in play.

A Kota Formation stegosaur: the distribution chapter of "The Dinosauria II" includes an indeterminate thyreophoran from the Kota Formation. This is probably the specimen recently dubbed "Andhrasaurus".

A Kallamedu Formation stegosaur: based on the description of the specific fossils recovered, this is Dravidosaurus, the amazing stegosaur that can transform into a plesiosaur. The funny thing is, like Secernosaurus, this genus had been named before 1982 (1979), and was included in the text previously as its own genus.

Ankylosaurs:
A skull from Sary Agach, Kazakhstan: there is no name currently attached to this material that I can find. It was originally published in Riabinin (1938).

"Stegosaurus" madagascariensis teeth: this species has long been a problem, although we can be reasonably certain that the teeth are not stegosaurian. The popular choices have been Simosuchus/a similar crocodylomorph or an ankylosaurian, more the latter at the moment (Maidment 2010).

There is also an interesting blurb in the Scelidosaurus entry, that this genus was an ornithopod (or even a hypsilophodont). I tracked down the source of this to Thulborn (1977), assuming that something had been misinterpreted or that it would make more sense in the original document. It didn't. This particular publication has not aged well.

Ceratopsians:
Fragments from Coahuila, Mexico reported by Janensch: Well, we do have a ceratopsid from Coahuila now: Coahuilaceratops. However, none of the material reported by Janensch is included in it (Loewen et al. 2010). It is possible that the earlier material may represent Coahuilaceratops, in whole or in part, or it may not have anything to do with it.

"Monoclonius" recurvicornis: We went over this species in some detail a couple of months ago. Suffice it to say that it remains a loose end.

References:

Irmis, R.B., W. G. Parker, S. J. Nesbitt, and J. Liu. 2007. Early ornithischian dinosaurs: the Triassic record. Historical Biology 19(1):3–22.

Foster, J. R. 2003. Paleoecological analysis of the vertebrate fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain region, U.S.A. New Mexico Museum of Natural History and Science, Albuquerque, New Mexico. Bulletin 23.

Glut, D. F. 1982. The new dinosaur dictionary. Citadel Press, Secaucus, New Jersey.

Glut, D. F. 1997. Dinosaurs: the encyclopedia. McFarland & Co., Jefferson, North Carolina.

Loewen, M. A., S. D. Sampson, E. K. Lund, A. A. Farke, M. C. Aguillón-Martínez, C. A. de Leon, R. A. Rodríguez-de la Rosa, M. A. Getty, and D. A. Eberth. 2010. Horned dinosaurs (Ornithischia: Ceratopsidae) from the Upper Cretaceous (Campanian) Cerro del Pueblo Formation, Coahuila, Mexico. Pages 99–116 in M. J. Ryan, B. J. Chinnery-Allgeier, and D. A. Eberth, editors. New perspectives on horned dinosaurs: the Royal Tyrrell Museum Ceratopsian Symposium. Indiana University Press, Bloomington, Indiana.

Maidment, S. C. R. 2010. Stegosauria: a historical review of the body fossil record and phylogenetic relationships. Swiss Journal of Geosciences 103:199–210.

Norman, D. B. and H.-D. Sues. 2000. Ornithopods from Kazakhstan, Mongolia and Siberia. Pages 462–479 in M. J. Benton, M. A. Shishkin, D. A. Unwin, and E. N. Kurochkin. The age of dinosaurs in Russia and Mongolia. Cambridge University Press, Cambridge, United Kingdom.

Riabinin, A. R. 1938 [Some results of the studies of the Upper Cretaceous dinosaurian fauna from the vicinity of the station Sary-Agach, South Kazakhstan]. [Problems of Paleontology Vol. IV.]

Thulborn, R. A. 1977. Relationships of the Lower Jurassic dinosaur Scelidosaurus harrisonii. Journal of Paleontology 51(4):725–739.

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