Re: Tanystropheus egg question

[David Peters <davidrpeters@earthlink.net>]

>   I don't see why a really long neck should be a prevention for being
> egg-born given that extremely long vertebral columns can still be curled
> up inside an egg, as in snakes, and adding hypothetical legs to the snake
> bauplän would not interfere in the typical ovoid egg design, nor prevent
> the idea of a hard egg. If the same body form can be encapsulated in an
> amniotic sac, then it may just as easily be so in a calcified shell
> _around_ the same amniotic sac.

Snakes have _how_ many flexible verts? Tanystropheus has none. It's stiff.
If you want to see how a sister taxon with a much shorter neck with 12 verts 
handles the situation, check out Olsen's paper on Tanytrachelos. Fig. 4.

Okay, the egg is shaped like a foot-long hot dog.

>
>
> <Multi-cusped teeth, big eyes and a short snout are also found in basal
> pterosaurs, longisquama, langobardisaurus, and other prolacertiforms of
> similar size. The big Tanys are definitely the oddballs.>
>
>   To my knowledge, the impressions of the teeth in *Longisquama* are so
> small and the granulation of the slab so large that determination of
> multiple cusps would be extremely difficult to support.

Not true.


> After seeing a
> cast of the holotype specimen in person, I am at once amazed at how truly
> tiny this thing is;

It's the same size as MPUM 6009, the basalmost pterosaur. Only the head is a 
little larger in the ptero, the wing finger alot longer, and the legs are 
shorter. Check out: pterosaurinfo.com > taxa > basal pterosaur clade


> the animal on a whole is smaller than a newborn
> kitten, and the granulation very distinct, especially above the preserved
> skeletal elements, where anything seen seems to be more or less in the eye
> of the beholder.

Keyword: cast. or cast of a mold of a cast.


> Let's also note that large orbits occur in anurognathids,

true. and they're only one step away from the basalmost pterosaur, which also 
has a short snout.

>
> and that paedomorphosism is possible here, and that basal pterosaurs will
> have similar designs, orbit to skull ratios caried on with
> *Rhamphorhynchus,* as well as -- and especially so -- in *Sordes.*

In these cases, large orbits are primitive to the Pterosauria.

> This is
> a paedomorphic trend, one would think, but perhaps not indicative of a
> trend linking the short-armed, long-legged quadrupedal prolacertiforms
> with the short-legged, long-armed, volant and semi-quadrupedal pterosaurs,
> which despite extensive recovery of Triassic prolacertiforms and basal
> archosauromorphans, still fail to yield an earlier, semi-winged or
> wingless pseudo-pterosaur.

See pterosaurinfo.com > taxa > Longisquama. This is the semi-winged form you've 
been looking for. And you can read all about story behind the transtion at: 
pterosaurinfo.com > origins > Prehistoric Times article

>
>
>   Cheers,
>
> =====
> Jaime A. Headden
>

Best,

David Peters
St. Louis

PS. I'm taking a closer look at the Tanystropheus Tanytrachelos epipubic bone 
question. There are some inconsistencies if anyone wants to get up to speed on 
this subject and have a conversation. And please don't repeat what you've read
about these enigmas. Start fresh and do your tracings.