Re: How are columbiformes (doves and pigeons) related to psittaciformes?

["John Pourtless" <vindexurvogel@hotmail.com>]

> From: "Mickey Mortimer" <Mickey_Mortimer111@msn.com>
> Reply-To: Mickey_Mortimer111@msn.com
> To: <dinosaur@usc.edu>
> Subject: Re: How are columbiformes (doves and pigeons) related to 
> psittaciformes?
> Date: Mon, 10 May 2004 21:34:41 -0700


> I wouldn't be convinced on my authority of pelecaniform phylogeny either.
> Luckily for us, you'll note I included a reference to someone else's work 
> in
> my statement.  This would be Bonnie Gulas-Wroblewski
> (http://www.fmnh.org/research_collections/pritzker_lab/pritzker/people/grad_
> gulas.html), whose abstract I copy below.
>
> Gulas-Wroblewski, B.E. 2003. Limnofregata: not a frigatebird anymore.
> Journal of Vertebrate Paleontology. 23(3) 58A.
> Limnofregata azygosternon, a fossil pelecaniform (Aves: Pelecaniformes) 
> from
> the
> Green River Formation of Wyoming, has traditionally been cited as the 
> oldest
> occurrence of
> the family Fregatidae, which includes the extant genus Fregata
> (frigatebirds). However, a
> cladistic analysis employing 153 morphological characters across eleven 
> taxa
> (nine extant
> members of Pelecaniformes, two outgroup representatives, and the holotype 
> of
> Limnofregata)
> places L. azygosternon as the sister-taxon to a clade containing the extant
> Sula (boobies) and
> Morus (gannets). This position is supported by the following 
> synapomorphies:
> 1. extensive
> papillae remigalis caudalis of the ulna absent or greatly reduced, 2. edge
> of the bicipital surface
> of the humerus does not reach over the sulcus ligamenti transverses, 3.
> crista cnemialis
> lateralis of the tibiotarsus slightly hooked. The relocation of this fossil
> genus to the Sulidae, a
> more derived clade within Pelecaniformes than Fregatidae, affects previous
> molecular clock.
> hypotheses of early neornithine radiation that used Limnofregata as a
> calibration point.
> Furthermore, the oldest occurrence of a fossil sulid is shifted back to the
> early Eocene (53.5-
> 48.5 Ma), providing insight into the early diversification of one of the
> basal orders within
> Neornithes.


Until I read this paper (and re-read Olson 1977b) I will not comment too 
much, but as I recall Olson's argumentation for the fregatid affinities of 
*Limnofregata* was fairly robust and I am hardly impressed by the evidence 
presented in the abstract of the Gulas-Wrobleski paper.

> I think Gulas-Wroblewski's work demonstrates a different, but related,
> point- Even given complete skeletons (as were available to Olson in 1977),
> phylogenetic identification can be just as wrong as if the specimen were a
> single element.  So if your wish is to postpone identification of specimens
> until we "know enough" about the taxon to place it securely in a clade,
> you'll have to wait until we know everything.  You can say a partial 
> dentary
> isn't enough to responsibly place a taxon, but how complete must a specimen
> for us to be able to place it responsibly?  Apparently even a complete
> specimen (the holotype of Limnofregata even has feather impressions) isn't
> enough to place a taxon unambiguously.  So based only on completeness,
> there's going to be no real dividing line between when it's appropriate to
> refer a taxon to a clade, and when it's not.
> Often fragmentary remains are "useless", and often they don't help 
> determine
> the phylogeny of a clade.  But there's more to paleontology than phylogeny
> (*Jaime Headden drops dead upon noting I said this* :-) ).  Scraps of bone
> can often increase the known spatiotemporal distribution of clades for
> instance, as Stidham's parrot is reported to do.  Is Stidham's claim of
> Maastrichtian loriines really extraordinary and lacking in careful 
> research?
> He seemed to have examined all other possibilities for the jaw and ruled
> them out on morphological grounds.  Molecular evidence and the fossil 
> record
> are continuing to push back the emergence of many neornithine clades, so
> that a Late Maastrichtian parrot doesn't seem so unlikely.  After all, the
> history of paleontology has also demonstrated clades often have much 
> greater
> temporal ranges than we thought.  This latter fact diminishes the utility 
> of
> dismissing seemingly out of place remains as mimics of the clades they
> resemble.  If we used such a philosophy, it would be quite subjective how
> out of place a specimen must be to be removed from the taxon it appears to
> belong to.  Better to work on a purely morphological basis, and treat all
> specimens as equally likely to be anything.
>
> Mickey Mortimer

You continue to distort my position.  There is a distinct difference between 
arguing that a badly preserved scrap of jaw is not sufficient evidence to 
push back the origin of Psittaciformes to the Maastrichtian, and arguing 
that one must know everything there is to know about a specimen before 
making any conclusions about it.  I do not recall denying that often taxa do 
have far earlier origins than anticipated, or denying that fragments can be 
useful in determining as much (provided they are diagnostic enough to permit 
referral to the taxon in question).  You can imply arguments I am not making 
as much as you want, but it will have no basis in reality.

JGK

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