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Re: Sky Monsters - Nat. Geo. channel



On 1/24/06, Tim Williams <twilliams_alpha@hotmail.com> wrote:
>
> Irrespective of whether you go the prolacertiform route or the archosaur
> route, the *exact* phylogenetic affinities of the Pterosauria remain hazy.
> I think the evidence supporting archosaur affinities trumps the evidence
> favoring prolacertiform affinities; but the _Scleromochlus_-Pterosauria link
> is nevertheless quite weak.  In other words, one can find support for
> regarding pterosaurs as archosaurs without necessarily advocating
> _Scleromochlus_ as the sister taxon to the Pterosauria.

CMIIW, but don't both the ornithodiran archosaur and the
prolacertiform hypotheses advocate _Sharovipteryx mirabilis_ as a
pterosaur sister taxon?

> There are new Triassic taxa that are said to be a non-pterosaurian
> pterosauromorphs, and may shed light on pterosaur origins.  Both taxa have
> given names (in a dissertation) [...] Some of the material previously 
> referred to
> _Protoavis texensis_ may be referrable to one of these putative
> pterosauromorphs.

Exciting!

> As Renato said, the earliest-known fossil bats reveal nothing about what the
> pre-flight chiropterans might have looked like.  Also, there are no
> identifiable chiropteran sister taxa in the fossil record.  In other words,
> we have no chiropteran equivalent for _Archaeopteryx_, nor a chiropteran
> equivalent for the deinonychosaurs (or any other maniraptoran for that
> matter).

As I recall, there was a talk at SVP this year showing that the
mutation for yielding long fingers is relatively simple, so bats may
have evolved practically overnight (in geological terms, of course).
Of course, you'd still expect there to be some gliding outgroups, and
we haven't found those, but small, arboreal animals (particularly
tropical rainforest dwellers) are notoriously rare in the fossil
record.

I missed that talk, unfortunately, but perhaps someone else can say more.
--
Mike Keesey
The Dinosauricon: http://dino.lm.com
Parry & Carney: http://parryandcarney.com