Even with my limited grasp of the ornithischian and hadrosaurs in particular, I’m aware of the odd story of the ‘horn’ of Tsintaosaurus and thanks to the presence of a great mount and the original skull itself on display at the IVPP, it seemed suitable to retell the tale and continue this little sequence of ornithischian posts.
Many hadrosaurs have crests of some description on their heads that reach a peak in things like Parasaurolophus and Corythosaurus and Tsintaosaurus appears at first glance to be no exception. There’s a fairly obvious long bony shaft coming out of the front of the skull and rising into the air, and this was how it was originally described.
However, a later look at the specimen suggested that this was misleading. It’s not too clear from these photos I’m afraid, but it’s pretty obvious that the ‘crest’ fits pretty well into the slot of the middle of the skull. In other words, it looks suspiciously like there was in fact no crest and that this fossil merely had its nasal bones massively skewed up in the air to give an illusion of a crest when in fact there was none.
However! This position then reversed again with the discovery of another specimen which suggested that there was a crest. This specimen has exactly the same morphology as the first and since it already would have been a very odd pathology or bit of preservation to bend those bones up in that way one, to have done so twice in exactly the same way shows that the crest is in fact genuine. Thus, the crest is genuine and Tsintaosaurus really does have this unusual and dramatic crest.
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Dave Hone's Archosaur Musings 
Cool post. The odd crest might not be that surprising given that other lambeosaurines appear to have had very tall erect crests, such as Olorotitan (though the overall shape of Olorotitan’s crest is obviously different from Tsintaosaurus).
Do you have any citations for the second specimen which apparently shows the upright spike is the right orientation?
Cheers,
Nick
=)
I know others have the anterior upright crest, but not, I think, with the gaping hole in the front of the face too. The paper I think you want is Buffetaut & Tong, 1993. I have a copy floating around but have to confess I didn’t read it before writing the post.
Nick,
Buffetaut, E., Tong-Buffetaut, H., 1993. Tsintaosaurus spinorhinus Young and Tanius sinensis Wiman: a preliminary comparative study of two hadrosaurs from the Upper Cretaceous of China. Comptes Rendus de l’Acade´mie des Sciences, Paris, series 2, Sciences de la Terre et des Plane´ tes 317, 1255–1261.
Thanks for adding that, I really don’t know where my copy is to hunt down all the detials.
Albert Prieto-Marquez and Jon Wagner presented a paper at the Bristol SVP arguing for a (not-too-different-from-Olorotitan) crest in Tsintaosaurus, based on some material from the type locality:
Prieto-Marquez, A. & J. Wagner. 2009. A new clade of Eurasian Lambeosaurinae (Dinosauria, Ornithopoda), with a new reconstruction of Tsintaosaurus. JVP 29 (Suppl. to 3): 167A.
(Dave: I’ll try and get you the files tomorrow!)
I missed that completely. Thanks for the head’s up on that Tom.
Ack, Dr. Holtz beat me to it. The new crest reconstruction, that is. I didn’t know the paper was out–could somebody send me a copy, too? 🙂
Paper itself is not out: that is just the SVP abstract.
As Tom notes, at SVP 2009 Albert showed that the rod-like crest had a weird lump at its tip (known from several specimens). This led him to conclude that true crest shape was very different from the unicorn-like reconstruction shown typically. Looked very neat.
Is there the possibility that these process at the head of the Tsintaosaurus spanned up a kind of sail, because of the bifurcated tip of the process?
Well there’s always a possibility, but it’s hard to say. My instinct would be not, but without any good correlates in extant organisms or soft-tissue preservation you never knows for sure. If nothing else it would be odd to have one at the front of the head here as it might interfere with the nostrils as they have to have an exit on that part of the face too.
While the odd preservation of the Tsintaosaurus crest is interesting, one must look at the entire functional anatomy of the skull in order to determine if the condition is “real”. In this case, the teeth do not align, or even come together, for that matter, when the jaws are closed.
Reconstructing Tsintaosaurus with the “crest” pulled down to contact the premaxilla as its sutural contacts indicate changes the geometry of the skull and allows the teeth to align.
I personally cannot think of any other example of an animal so well-adapted for chewing evolving a non-chewing, morphologically unstable skull configuration. In my opinion, it is much more likely that: a. this particular structure was a weak spot that allowed a wound to be healed in a grotesque manner in a number of individuals or b. postdepositional distortion acted upon said weak spot in similar ways on a couple of specimens. The alternative, that fast-growing teeth with contact wear patterns weren’t in contact with each other, is untenable.
As Sir Arthur Conan Doyle once wrote, “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”
A lot of that ‘odd preservation’ is pretty normal. Few fossils come our perfectly and skulls especially are prone to come apart and get twisted and distorted in the process (look at the skull of Sue). Things often *don’t* line up for this very reason.
And as noted, there are multiple specimens in any case, very strongly suggesting that the crest is normal and represents the correct condition in the skull.