[Taxacom] More evidence turtles are diapsids

[Kenneth Kinman]

Dear All,
      A recent paper provides more evidence that turtles are well within
the diapsid clade of reptiles (and therefore not true anapsids).  The
citation and abstract are given below.  
     Note that they use the clade name "Pantestudines" in the title,
which I believe should actually be spelled "Pan-Testudines".  If we are
going to have to put up with all these new PhyloCode clade names, the
"Pan-" names should be hyphenated to clearly distinguish them as such
(and I believe that PhyloCode is going to mandate this).  
      --------Ken Kinman
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An Archosaur-Like Laterosphenoid in Early Turtles (Reptilia:
Pantestudines); by Bhullar and Bever, 2009.   Breviora, 518:1-11.

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.