[Taxacom] More evidence turtles are diapsids
J. Kirk Fitzhugh
kfitzhugh at nhm.org
Mon Oct 19 15:58:12 CDT 2009
I'd be fascinated to actually see a valid deduction of morphology from a
moleculoid tree, or vice versa. It's not that difficult to follow the
rules of deduction, so why not show us? I continue not to understand why
the most basic mechanics of testing that have been established for all
fields of science aren't being applied here.
Incongruence/congruence is a shame. It's meaningless. You're comparing
two disparate hypotheses that have no relevance to each other. The only
relevance those hypotheses have is to the characters used to infer the
respective hypotheses. The nature of the evidence to which you refer is
only evidence prompting particular hypotheses, not valid test evidence.
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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
John Grehan wrote:
> In this case the morphology may corroborate the molecular prediction,
> but what would have happened if it did not? Would the morphological
> evidence have just been dismissed as it is in the hominid field?
>
> I read the arguments over testing and deduction, which seem to have been
> around for as long as I can remember. Whether or not it is a 'test' or
> not, morphology represents a source of evidence that may or may not
> corroborate linear molecular similarity. If the results of each are
> incongruent the decision to accept the molecular result renders the
> fossil record for that group uninformative. This is what has happened
> with Ardipithecus where the fossil is said to belong to a group that
> cannot be substantiated by any direct evidence and yet this is able to
> be said without anyone batting an eyelid.
>
> John Grehan
>
>
>
>
>> -----Original Message-----
>> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
>> bounces at mailman.nhm.ku.edu] On Behalf Of mivie at montana.edu
>> Sent: Friday, October 16, 2009 12:20 PM
>> To: Kenneth Kinman
>> Cc: taxacom at mailman.nhm.ku.edu
>> Subject: Re: [Taxacom] More evidence turtles are diapsids
>>
>> 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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