[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: was: Pterosaur.net now: pteroid



2010/1/15 David Peters <davidpeters@att.net>:
> That facet Chris and Jim are looking at on the preaxial carpal is not the 
> facet for the articulation of the pteroid.

David, I for sure have seen much less pterosaur specimens than you,
but, judging from what is published, it seems to me that an articular
facet is better marked on the medial side of the preaxial carpal of
one old specimen of Pteranodon, as shown by Bennett (2007), than on
the anteroventral surface of the proximal syncarpal of Anhanguera, in
the same paper. I was unable to see a differentiated articular surface
in other published sources.

> Absolutely NO specimens preserve the carpus articulated in this fashion. 
> None. Zero.

I think that the pteroid is also preserved contacting the radius in
Eudimorphodon, as you show in your paper, and contacting no bone in
many pterosaurs, so I doubt in situ associations. In the Anhanguera
specimen shown by Bennett (2007) you do not have the pteroid
articulated to the preaxial carpal.

> Send jpegs of exceptions if you can possibly find them. They don't exist. If 
> they did, Chris would have included them in his  2007 paper.

I would have to re-check, but I found an example of pteroid contacting
the lateral carpal at its articular end, in Wellnhofer 1975, Tafel 20,
fig. 3, a Rhamphorhynchus specimen in the American Museum.

Wellnhofer, P. 1975. Die Rhamphorhynchoidea (Pterosauria) der
Oberjura-Plattenkalke Süddeutschlands. Palaeontographica, Abt. A, 148:
1-33; 148: 132-186; 149: 1-30.

> And try to imagine the big angle iron pteroid of Nyctosaurus articulated as 
> Bennett suggests. So, it's back to the drawing board.

Bennett (2007) wrote there was a rostroventrally directed facet for
the pteroid in the preaxial carpal of Nyctosaurus, if I remember
correctly, which will still have the pteroid pointing medially.

> Given that it's not a bone/bone articulation, what is that little spot on the 
> inboard preaxial carpal all about? Consider the possibility of a short 
> ligament between the preaxial carpal and the pteroid, attaching at the 
> pteroid bend and beyond.

Humm... but as far as I remember, it is a smooth facet, right? should
not a ligamentary surface be more rugose?