Tetrapod Zoology

i-cc8dc10f032dfcf897544c33c896b6f9-Udanoceratops_skull_wikipedia copy.jpg

Once more, I’m going to start recycling some of those dinosaur texts written for the defunct field guide (for the back-story on that project see the ornithomimosaur article here). This time round, I’ll get through some of the ceratopsians [adjacent skull reconstruction from wikipedia, and based on an image by Jaime Headden].

One of the most poorly known ceratopsians, Udanoceratops tschizhovi was a Mongolian species from the Santonian-Campanian Djadokhta Formation. Named in 1992 by Sergei Kurzanov, the holotype consists of an incomplete skull (the frill and everything around the orbital region are reconstructed in the image above) and associated partial skeleton. A juvenile specimen has also been identified. The skull is approximately 60 cm long, so this was a reasonably large animal, with a total length estimated at 4 m. Its short, deep skull is highly distinctive, and it lacks the peg-like premaxillary teeth present in Protoceratops. It also differs from these genera in having a particularly deep lower jaw that was curved along its length. Most studies find Udanoceratops to be most closely related to to the North American taxa Leptoceratops and Prenoceratops (Chinnery & Weishampel 1998, Xu et al. 2002, Chinnery 2004, Makovicky & Norell 2006), in which case it’s a member of Leptoceratopsidae [Udanoceratops life restoration below from wikipedia; by Arthur Weasley].

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It seems that at least some leptoceratopsids looked insane: Greg Paul reconstructed Leptoceratops, and found that it had a proportionally gigantic skull and a really short tail (Paul 1996). Dale Russell’s better known reconstruction (Russell 1970) is far less extreme and more widely known, but it’s a composite based on scaled data from more than one specimen. Unfortunately, the precise reasoning behind either reconstruction has yet to be provided: a very quick look at the data and images provided by Sternberg (1951) indicates that Paul’s reconstruction is more correctly proportioned. Back to Udanoceratops: I found the photo below here. It’s labelled as Udanoceratops but differs substantially from the holotype skull (much smaller nostril, jugal flange when one is lacking in Udanoceratops, deeper anterior end of dentary, etc.) – so, what is it?

i-e843bf1071b5fbd9afbe060a524716f3-Udanoceratops_photo.jpg

One last thing: Tereschenko (2008) argued that Udanoceratops was facultatively aquatic. For reasons that are never really explained in the paper, Tereschenko apparently assumed amphibious or aquatic habits in most non-ceratopsid ceratopsians: I think because the long neural spines on the caudal vertebrae were taken to evidence regular swimming habits, and because the fossils of these dinosaurs are often associated with lakes or ponds. The paper is extremely flawed and the conclusions are almost certainly erroneous. However, it remains unknown why at least some non-ceratopsid ceratopsians possessed such tall neural spines on their caudal vertebrae. A role in display has been suggested – is it coincidental that Psittacosaurus (at least) had quill-like bristles on its tail?

Refs – –

Chinnery, B. 2004. Description of Prenoceratops pieganensis gen. et sp. nov. (Dinosauria: Neoceratopsia) from the Two Medicine Formation of Montana. Journal of Vertebrate Paleontology 24, 572-590.

Chinnery, B. J. & Weishampel, D. B. 1998. Montanoceratops cerorhynchus (Dinosauria: Ceratopsia) and relationships among basal neoceratopsians. Journal of Vertebrate Paleontology 18, 569-585.

Makovicky, P. J. & Norell, M. A. 2006. Yamaceratops dorngobiensis, a new primitive ceratopsian (Dinosauria: Ornithischia) from the Cretaceous of Mongolia. American Museum Novitates 3530, 1-42.

Paul, G. S. 1996. The Complete Illustrated Guide to Dinosaur Skeletons. Gakken.

Russell, D. A. 1970. A skeletal reconstruction of Leptoceratops gracilis from the upper Edmonton Formation (Cretaceous) of Alberta. Canadian Journal of Earth Sciences 7, 181-184.

Sternberg, C. M. 1951. Complete skeleton of Leptoceratops gracilis Brown from the Upper Edmonton Member on the Red Deer River, Alberta. Bulletin of the National Museum of Canada 123, 225-255.

Tereschenko, V. S. 2008. Adaptive features of protoceratopoids (Ornithischia: Neoceratopsia). Paleontological Journal 42, 273-286.

Xu, X., Makovicky, P. J., Wang, X.-l., Norell, M. A. & You, H.-l. 2002. A ceratopsian dinosaur from China and the early evolution of Ceratopsia. Nature 416, 314-317.

Comments

  1. #1 David Marjanović
    April 18, 2009

    The species name should win a prize for least consistent transcription.

    The genus name, BTW, contains a Mongolian place name that was shifted into Russian while keeping the Mongolian vowel harmony: it’s Üüden Sayr.

  2. #2 Richard Carter, FCD
    April 18, 2009

    The top diagram looks just like a pair of gardening secateurs. Wouldn’t Secateurus be a fantastic name for a dinosaur?

  3. #3 Zach Miller
    April 18, 2009

    If that photograph really is Udanoceratops, then it’s an enormous leptoceratopsid!

  4. #4 Metalraptor
    April 18, 2009

    Perhaps the enlarged neural spines had something to do with the quills, provided some sort of muscular anchorage. The tails of ceratopsians may have bore big, nasty quills, seeing as the one definite quilled ceratopsian only has noticable quills on the tail. These quills could have been used for weaponry (swinging said tail) as well as intimidation (making the animal look overall larger). Of course, I don’t know how flexible ceratopsian tails were; I know they were more flexible than the stiff tails of the hadrosaurs, but depending on how stiff they are, my speculation here may be implausible. Of course whoever said the tail needed to be swung to be a weapon. Porcupines have their biggest quills on their hips and tail, to prevent attack from predators.

  5. #5 Darren Naish
    April 18, 2009

    What’s the deal with the Triceratops specimen that supposedly possesses tail quills? I keep hearing about it but have yet to see anything in print. Does anyone know?

  6. #6 Metalraptor
    April 18, 2009

    Yeah, I know a little. Basically the specimen has what looks like pores where the quills go in or something like that, interspersed among its scales. Or something else that’s a lot more definite, not a lot has been said by it. The reason being is probably because it was found by the Black Hills Institute, and its with them for now. Unknown if it will actually make its way into a museum or something for study. I asked ceratopsian expert Dr. Michael Ryan about it, and he doesn’t seem to convinced. He thinks they might be pores for oozing toxin or something (it had something to do with a Gila Monster I think), meaning that under that idea, Triceratops had poisonous flesh. Sorry I can’t tell much more, all this info is about a year old, and I’ve forgotten a bunch of it. But whatever it is, it really needs good study. Its implications could be staggering for ceratopsian study.

  7. #7 Jaime A. Headden
    April 18, 2009

    It’s awesome to see Udanoceratops make it to the blogosphere, and my lovely Nutcraker skull as the frontis for this post. In defense of Tereschenko, however, the reason he purports the subaquatic lifestyle has a lot to do with the apparent sculling function of the tail, as it bears broad transverse processes throughout the caudal region, long processes along the tail a little further than you’d expect in a stiff-tailed animal or even a theropod with mobile tails. This gives the tail a robust musculature for most of its length, which is seeming at odds with a surface dwelling tetrapod (I am not sure how much work Tereschenko has had looking at lacertilian tails, which show some similar features, though). The sculling hypothesis is a natural one, but Tereschenko has published frequently on it (usually part of his Protoceratops papers on vertebral and limb posture).

    Zach, Udano is in fact the largest of all leptoceratopsids and, to be honest, may be the largest non-Ceratopsoidean coronosaur. Montanoceratops, which comes close, though, has it in the running.

  8. #8 Alec T
    April 18, 2009

    Is that a Skeksis skull?

  9. #9 Nathan Myers
    April 19, 2009

    I suppose it’s the posture that makes that U. tschizhovi skull seem so jolly. It can’t be circumstances because, you know, it’s dead.

  10. #10 Hai~Ren
    April 19, 2009

    Thanks for sharing more about this less well-known ceratopsian. The ceratopsids, Protoceratops and Psittacosaurus receive so much attention that it’s easy to forget that there were so many more ceratopsians out there.

    It would be great if you had the time to do a series on leptoceratopsids.

  11. #11 DDeden
    April 19, 2009

    Purely a guess: (if the neck was typically robust) did it grasp a juicy soft thick plant stem with the beak with head angled, and use the molars to chomp on it? I’m thinking a parallel with beavers, but with the head twisted to eat, and the flat tail (but vertically oriented) to swim in swamps.
    Shorter than expected tails often relate to sitting in water while feeding in a diagonal/seated posture (frogs, Ndoki swamp lowland gorillas) so perhaps a diet of wetland plants (like papyrus sedge rhyzomes), as a part-time amphibious feeder.

  12. #12 Darren Naish
    April 19, 2009

    Thanks to all for comments. I’m particularly interested in Jaime’s claim that Tereschenko’s proposal of aquatic/amphibious habits is supported by broad transverse processes that provide a hefty musculature. Well, no. The transverse processes are small and short in these animals: in fact, Udanoceratops (figured Tereschenko 2008) has tiny processes, smaller than those of psittacosaurs and ceratopsids. Nor do they extend a long way along the tail. Tereschenko regards the tails as ‘very high and compressed laterally’ (2008, p. 277) and does not refer to, nor reconstruct (2008, p. 278), width across the tail. Tereschenko does compare cross-sections of ceratopsian tails with cross-sections of alligator and giant salamander tails: there are vague similarities, but they’re very vague (as in, the similarities would be seen in any tetrapod with a tail!) – and the ridiculous neural spines of the ceratopsian tails make them radically different from the alleged analogues.

    I cannot see any reason for thinking that these ceratopsians were any more aquatic than, say, wild pigs or peccaries.

  13. #13 David Marjanović
    April 19, 2009

    DDeden, the Djadokhta Formation is a semidesert sediment that consists mostly of sand dunes. That alone makes the lifestyle you suggest completely impossible.

    Oh, and, beavers use their feet and only their feet to swim. The tail just sticks out and serves to rid this large, compact animal of excess heat generated by its fast metabolism. It’s just a scaled-up rat tail.

  14. #14 Lukas Panzarin
    April 19, 2009

    Bagaceratops do not possess premaxillary teeth (contra Sereno), as the small specimens referred by Dong & Currie to Bagaceratops, and the Breviceratops holotype show no autapomorphy of Bagaceratops (except for the secondary antorbital fenestra, present also in Magnirostris, Zuniceratops, and some basal ceratopsids (Kirkland and Deblieux 2007)), so, as no ornithischian show a polimorphic premaxillary teeth number, is more conservative to consider those very young specimen as Coronosauria indet., or, tentatively referred to Breviceratops (given the unique combination of characters of this taxon: premaxillary teeth, secondary antorbital fenestra, at least 8 sacrals, and so on). Although Kurzanov referred some subadult and adult specimen to Breviceratops, these specimen lacks premaxillary teeth, and are very probably subadult and adult specimens of Bagaceratops (Makovicky 2006). Alifanov erected a plethora of new taxa (Lamaceratops, Platyceratops, and the recently described Gobiceratops…) based in part on these skulls, simply on minor features, which are known to be ontogenetic-related or polimorphic within a genus, and are very probably junior synonyms of Bagaceratops (Makovicky 2006).

    I think the very short tail of Leptoceratops by Greg Paul is based on the juvenile specimen NMC 8887, which have 10 vertebrae less than the larger (presumibly subadult) NMC 8888, with at least 48 vertebrae (Sternberg 1951).

    About Udanoceratops…An almost complete skull with a well developed frill is now known (Tereschenko pers. comm. 2009), but remain (at present) undescribed.
    The specimen of the photo clearly do not belong to Udanoceratops…I don’t know what is it, but the double ridge on the nasal are very similar to Protoceratops spp., moreover, the postquadratic process of the squamosal, and the relatively straight dentary margin are found in coronosaurs more derived than leptoceratopsids. I suspect it could be a subadult specimen of Protoceratops hellenikorhinus, which is, together with Udano, the largest
    ‘protoceratopsian’…
    who knows?

  15. #15 Darren Naish
    April 19, 2009

    Thanks for that Lukas. I will change the reference to premaxillary teeth in Bagaceratops: I thought that it lacked them, but relied on You & Dodson (2004) who state, erroneously, that these teeth are present, whoops. As for Magnirostris, I agree with Makovicky & Norell (2006) that it’s most likely a specimen of Bagaceratops. Regarding the short tail of Leptoceratops, Paul’s reconstruction has 43 caudals whereas NMC 8887 has 38 according to Sternberg. Remember that animals do not generally add new vertebrae as they grow, so even NMC 8887 would have been a short-tailed adult. As for that large mystery skull – hmm, I really wonder if anyone knows the answer. Oh, and do you know what the frill looks like on the new Udanoceratops specimen?

    Ref – –

    You, H. & Dodson, P. 2004. Basal Ceratopsia. In Weishampel, D. B., Dodson, P. & Osmólska, H. (eds) The Dinosauria, Second Edition. University of California Press (Berkeley), pp. 478-493.

  16. #16 Blind Squirrel FCD
    April 19, 2009

    Metalraptor: I’m not sure if you were claiming the contrary, but porcupines do actively use their tail with a flipping motion to drive quills into offenders.

    Somewhat OT: A woman who works in my EE center hand raised a porky as a pet. (not recommended: they are surly, stupid and ungrateful.) She can pick it up barehanded without hurting herself.

  17. #17 Darren Naish
    April 19, 2009

    Note regarding the short tail and weird proportions given to Leptoceratops by Greg Paul: according to Paul & Christiansen (2000), the reconstruction is based on NMC 8889. But this can’t be right as that specimen lacks a tail and pelvis! Argh!

    Ref – –

    Paul, G. S. & Christiansen, P. 2000. Forelimb posture in neoceratopsian dinosaurs: implications for gait and locomotion. Paleobiology 26, 450-465.

  18. #18 Steve Poropat
    April 20, 2009

    Hey Darren, great blog (never commented before so thought I might as well… I just searched Protoceratops hellenikorhinus on Google images and one of the images returned was this: http://www.dinosoria.com/dinosaures/protoceratops_cc01.jpg
    To my (admittedly untrained) eye, the skull depicted above looks quite like the one in this image… I admit, though, that the mandible appears somewhat deeper in the image above. Any thoughts?

  19. #19 Darren Naish
    April 20, 2009

    Thanks for that Steve. The original description of P. hellenikorhinus (Lambert et al. 2001) includes figures of the ‘young adult male’ specimen IMM 96BM2/1. It’s essentially identical to the skull figured above, so: yup, I think that’s what it is (I mean P. hellenikorhinus, not the specimen IMM 96BM2/1).

    Ref – –

    Lambert, O., Godefroit, P., Li, H., Shang, C.-Y. & Dong, Z.-M. 2001. A new species of Protoceratops (Dinosauria, Neoceratopsia) from the Late Cretaceous of Inner Mongolia (P. R. China). Bulletin de L’Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre 71-Supp., 5-28.

  20. #20 Jaime A. Headden
    April 20, 2009

    Darren,

    Also in defense of Tereschenko (but not his theory), I should note that Tereschenko’s theory is based largely on Bagaceratops, and the implication that the transverse processes are only shorter to crocodiles in comparison. This doesn’t support his hypothesis (since he’d need to establish a comparison of scullers and nonscullers, then test these taxa among them) and he argues that dorsal vertebrae are capable of some lateral flexibility.

    Tereschenko, V. A. 2008. Adaptive features of protoceratopoids (Ornithischia: Neoceratopsia). Paleontological Journal 42(3):273–286. [Original, earlier Russian version, Paleontologicheskii Zhurnal 2008(3):50–64.]

  21. #21 DDeden
    April 21, 2009

    @ DM: beaver using feet and tail to dive
    video link
    At the surface, only the feet propel while the tail reduces surface drag and adds buoyancy.

  22. #22 Eric
    June 18, 2009

    Yeah, I know a little. Basically the specimen has what looks like pores where the quills go in or something like that, interspersed among its scales. Or something else that’s a lot more definite, not a lot has been said by it. The reason being is probably because it was found by the “Black Hills Institute, and its with them for now. Unknown if it will actually make its way into a museum or something for study. I asked ceratopsian expert Dr. Michael Ryan about it, and he doesn’t seem to convinced. He thinks they might be pores for oozing toxin or something (it had something to do with a Gila Monster I think), meaning that under that idea, Triceratops had poisonous flesh. Sorry I can’t tell much more, all this info is about a year old, and I’ve forgotten a bunch of it. But whatever it is, it really needs good study. Its implications could be staggering for ceratopsian study.”

    Really? I thought that Peter Dodson was studying it. Didn’t he do a poster at SVP called skinning a triceratops where he showed the research that was going on with the specimen?

  23. #23 Eric
    June 21, 2009

    Besides, what wrongs with the Black Hills Institute?

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