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Re: Morpho v molecular (was Re: Tinamous: living dinosaurs)



There are morphological characters supporting a turtle-archosaur link:

BHULLAR, B.-A. S. and G. S. BEVER (2009). "AN ARCHOSAUR-LIKE LATEROSPHENOID IN 
EARLY TURTLES (REPTILIA: PANTESTUDINES)." Breviora 518.
    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.

 Ronald Orenstein
1825 Shady Creek Court
Mississauga, ON L5L 3W2
Canada
ronorenstein.blogspot.com

>  Similarly, there are many molecular relationships that aren't backed

>  up by morphological evidence (like you say for archosauromorph
>  turtles),