[Taxacom] More evidence turtles are diapsids

[J. Kirk Fitzhugh]

There is no 'test' of competing hypotheses here. Adding more effects to 
be explained by way of phylogeny simply means new hypotheses are 
inferred, replacing the old. No test has occurred, as no valid test 
implications stemming from the causal conditions stipulated by the 
hypothesis have been predicted.

Kirk

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
J. Kirk Fitzhugh, Ph.D.
Curator of Polychaetes
Invertebrate Zoology Section
Research & Collections Branch
Natural History Museum of Los Angeles County
900 Exposition Blvd
Los Angeles CA 90007
Phone: 213-763-3233
FAX: 213-746-2999
e-mail: kfitzhug at nhm.org
http://www.nhm.org/site/research-collections/polychaetous-annelids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


mivie at montana.edu wrote:
> This turtle study is an excellent example of how the
> molecular-morphological issue SHOULD work.  There is an established
> morphology-based system, challenged by new data from molecules, setting up
> a test of competing hypotheses.  The test then causes new character
> systems to be found and evaluated, leading to progress in the
> whole-evidence understanding of the group.
>
> Why this is so seldom done in the great apes is a mystery.  The recent
> Discovery special on Ardi was a perfect example of nonsense pseudoscience
> being presented to the  public about great ape origins.  In the program,
> they kept saying they expected a human ancestor that was chimp-like,
> showing a phylogram with chimps and humans having a most recent common
> ancestor. Then, when they found something non-chimp like, they just drew
> the same phylogram LONGER!  They never dealt with the idea of refutable
> hypotheses, nor that fact that the common ancestor of humans and chimps
> (at whatever level it existed) would not be expected to look like either. 
> No wonder so much of the public has a misunderstanding of evolution if we
> teach them about it with such sensational and misleading stuff!
>
> Makes me understand more why this drivel drives John G over the edge.
>
> Mike Ivie
>
>
>
>   
>> 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
>> ------------------------------------------------------------
>> 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.
>>
>>
>>
>>
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>>     
>
>
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