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Re: Archie skull pneumatics?

David Marjanovic wrote-
But why I'm writing this to the list is that I don't know about (5) and (6). I expect Witmer (who else?) knows what he's writing about here (he also cites
himself for both), but could someone give me a broader picture of where these characters occur?

Though, I imagine myself as the least likely to have ever responded, I find myself doing so regardless. Reminds me of "The Fellowship of the Ring", which I saw for the first time last night.

Do you mean to say that the reflexed hallux was absent in Archaeopteryx, or that the character is plesiomorphic for it, perhaps instead synapomorphic for Eumaniraptora, in light of *Microraptor* and *Scansoriopteryx*?

The elongated prenarial premaxilla is present in "enigmosaurs" (as David noted), spinosaurids (Sereno et al. 1998; Sues et al. 2002), and avians. I never really understood this character but I assume it could be related to dietary functions? Help... please.

I was under the impression that *A.* did not have an incomplete postorbital bar. I know that *Shuvuuia* does not (Suzuki et al. 2002), and that the contact between the postorbital and jugal is weak in *Bambiraptor* (Burnham et al. 2000).

How many non-avian theropods lack dental serrations anyway? I can only think of *Caudipteryx*, *Byronosaurus*, *Compsognathus*, and juvenile tyrannosaurids. I'm sure there must be more, but I can't think of them all. I thought that perhaps *Scansoriopteryx*, *Microraptor*, coelophysids, *Dilophosaurus*, and *Shuvuuia* might, but I can't be sure.

As for basal constriction of the teeth in non-avian theropods, I know it is present in *Caudipteryx*, *Microraptor*, *Shuvuuia*, segnosaurs, troodontids, and perhaps *Protarchaeopteryx*?

Perhaps he meant the enlargement of the cranial cavity relative to body size?

According to Xu et al. (2002), the caudal tympanic recess opens into the columellar recess in *Archaeopteryx*, *Sinovenator*, and *Shuvuuia*. Chiappe (2001) codes it as present in *Archaeopteryx*, *Mononykus*, *Shuvuuia*, *Hesperornis*, *Anas*, & troodontids. All the other avians in his analysis are coded as "?".

I cannot say anything much regarding the caudal maxillary sinus, because I am not familiar with it.

I agree that the distal reduction of the caudal prezygapophyses does seem suspect, especially when you take *Jeholornis* into account. However, I was not aware that *Microraptor* had a caudal count comparable to *Archaeopteryx* or other avians. There are other non-pygostylian theropods with very short tails, such as the avian *Jeholornis* (22), the curious *Protarchaeopteryx* (23), and *Caudipteryx* (22).

I wish the last character was not so vague...

Nick Gardner

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