Re: BANDS > PADS vs. PALS

[Augusto Haro <augustoharo@gmail.com>]

Regarding this theme of the bone wall thickness, I think that for this
character to be useful in the future, it has to be measured the
thickness of the wall and the diameter of the diaphysis at the same
point of section, as done by Nesbitt et al. 2009 (paper on Dromomeron
in JVP).

2010/2/15  <William_Parker@nps.gov>:
> Shuvosaurids (Shuvosaurus and Effigia) have 'hollow' limb-bones, thus this
> character is present in Pseudosuchia as well.
>
>
> ************************************************************************
> Bill Parker
> Vertebrate Paleontologist
> Division of Resource Management
> Petrified Forest National Park
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>             "Justin Tweet"
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>                                       Re: BANDS > PADS vs. PALS
>             02/14/2010 09:21
>             AM
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>             Please respond to
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>
>
> 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)
>
> -Justin
>
>
> ---------- Original Message ----------
> From: Augusto Haro <augustoharo@gmail.com>
> To: mickey_mortimer111@msn.com
> Cc: dinosaur@usc.edu
> 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 <mickey_mortimer111@msn.com>:
>>
>> 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
> clade?
>>
>>> 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
> taxa?
>>
>> 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
>>
>
>
>
>