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

Fwd: Pantestudines: the Turtle and Croc?



This surely may interest David more than others.

---------- Forwarded message ----------
From: Joao S. Lopes <josimo70@yahoo.com.br>
Date: 2009/10/7
Subject: Pantestudines: the Turtle and Croc?
To: vrtpaleo@usc.edu


Turtles' position in Reptilian phylogeny continues to generate
surprises and debates. I cannot download this article, but it provides
clues for place turtles closer to Archosauriformes.

Have we find the correct position of turtles... or not yet?



Breviora 518 :1-11. 2009
doi: 10.3099/0006-9698-518.1.1
An Archosaur-Like Laterosphenoid in Early Turtles (Reptilia: Pantestudines)
Bhart-Anjan S. Bhullar1 and Gabe S. Bever2
1Department
of Organismic and Evolutionary Biology, Harvard University, Biolabs
room 4110, 16 Divinity Avenue, Cambridge, Massachusetts 02138, U.S.A.
bhartanjan.bhullar@gmail.com
2Division
of Paleontology, American Museum of Natural History, Central Park West
at 79th Street, New York, New York 10024, U.S.A
Abstract
Turtles
are placed with increasing consistency by molecular phylogenetic
studies within Diapsida as sister to Archosauria, but published gross
morphology–based phylogenetic analyses do not recover this position.
Here, we present a previously unrecognized unique morphological
character offering support for this hypothesis: the presence in stem
turtles of a laterosphenoid ossification identical to that in
Archosauriformes. The laterosphenoid is a tripartite chondrocranial
ossification, consisting of an ossified pila antotica, pila metoptica,
and taenia medialis + planum supraseptale. It forms the anterior border
of the exit for the trigeminal nerve (V) and partially encloses the
exits for cranial nerves III, IV, and II. This ossification is unique
to turtles and Archosauriformes within Vertebrata. It has been
mistakenly dismissed as anatomically dissimilar in these two groups in
the past, so we provide a complete description and detailed analysis of
correspondence between turtles and Archosauriformes in each of its
embryologically distinct components. A preliminary phylogenetic
analysis suggests other potential synapomorphies of turtles and
archosaurs, including a row or rows of mid-dorsal dermal ossifications.

Joao SL



     ______________________________________________________
a quais são os assuntos do momento no Yahoo! +Buscados
http://br.maisbuscados.yahoo.com