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Re: BANDS > PADS vs. PALS
Shuvosaurids (Shuvosaurus and Effigia) have 'hollow' limb-bones, thus this
character is present in Pseudosuchia as well.
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Re: BANDS > PADS vs. PALS
Please respond to
Offhand, Anchisaurus (holotype) (Cope 1870) and the indeterminate East
Windsor sauropodomorph (Wyman 1855) have been described as having notably
thin-walled bones as well.
Cope, E. D. 1870. On the Megadactylus polyzelus of Hitchcock. American
Journal of Science (series 2) 49:390-392.
Wyman, J. 1855. Notice of fossil bones from the Red Sandstone of the
Connecticut River Valley.
American Journal of Science and Arts 20(60):394-397.
(both are on Google Books; search by article title)
---------- Original Message ----------
From: Augusto Haro <email@example.com>
Subject: Re: BANDS > PADS vs. PALS
Date: Sun, 14 Feb 2010 09:28:45 -0300
There is a section of a basal sauropodomorph femur of material
referred to "Thecodontosaurus" figured in Benton et al. 2000 ("Anatomy
of Thecodontosaurus", in JVP) which seems to present very thin walls.
2010/2/14 Michael Mortimer <firstname.lastname@example.org>:
> David Peters wrote-
>> Bennett (1996) did this. He noted that most of the synapomorphies
between pterosaurs and Scleromochlus resided in the hind limbs, with little
else to promote a relatioship. So he tested the removal of the hind limbs
to see where pterosaurs might end up. I think it was a good test. It
demonstrated that the position of pterosaurs within the Ornithodira was
based on flimsy evidence. It's never a good fit when one is forced to say
things like: "Pterosaurs appear suddenly in the fossil record." Adding
fenestrasaurs to the Bennett (1996) taxon list showed that this previously
untested clade had more pterosaur synapomorphies. That data has never been
tested, only dismissed (by Hone and Benton 2008).
> While I agree the protorosaur hypothesis was not usefully tested by
Benton and Hone, saying that a relationship is based on flimsy evidence if
it is no longer recovered when hindlimb characters are excluded seems
baseless. Which studies have been done eliminating hindlimb characters
from other analyses and comparing the results? Most oviraptorosaurian
characters are in the skull, but does that mean they're a poorly supported
>> Agreed. That's why you should look very carefully at the ornithodires
and try to see if you can find an elongated fifth toe. If you can't find
one among them, and you won't, it's time to look to other taxa. Also look
for digit IV longer than III. That's the primitive condition in pterosaurs.
> You and your key characters. By that reasoning, we'd exclude
therizinosaurids from Theropoda and sauropods from Dinosauromorpha.
>> Perhaps it does count for something. The skeleton of Sharovipteryx was
hollow. That's a start. Be interesting to see how far back air sacs go in
pterosaurs. Not sure that's been determined yet. Are they known in Triassic
> Hollow bones are often unrelated to pneumaticity, though the latter can
cause the former. Basically every theropod has hollow limb bones, but
almost no Mesozoic theropod has pneumatized limb bones. Bone wall
thickness is something that desperately needs examination in more
taxa. The old canard about only theropods (and pterosaurs) having hollow
bones is certainly false.
> Mickey Mortimer