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



David Marjanovic <david.marjanovic@gmx.at> wrote:

> Of course, somebody sit down with the matrix by Dyke & van Tuinen and
> actually test this speculation. And they should add a lot more fossils.


Agreed.  Despite the intuitive attraction of the idea that ratites are
united (to the exclusion of tinamous) by a suite of postcranial
characters associated with independent loss of flight, this hypothesis
has yet to be tested.


>>  By and large, paleo workers believe the molecular-based relationship
>>  (Whippomorpha) is wrong.
>
> Really?


Just to clarify, I didn't mean to give the impression that all (or
even most) paleontologists dismissing the hypothesis of any kind of
hippo-whale clade (Cetancodonta or Whippomorpha).  Sorry about that.
What I was saying is that those phylogenies based purely on
morphological/fossil data have not always upheld the derived position
of the Whippomorpha clade as recovered by molecular-based phylogenies.
 As noted by Tom, the morphological/fossil phylogenies usually recover
some configuration of Cetancodonta/Whippomorpha; but a link between
cetancodonts and ruminants (Cetruminantia), as proposed by
molecular-based phylogenies, is usually not supported by
morphological/fossil data.  The importance (or not) of the
anthracotheres in hippo and/or whale evolution is also the subject of
different viewpoints.  Having a hippo-whale clade as derived
artiodactyls, closest to ruminants, is the essence of the Whippomorpha
hypothesis (Gatesy et al., 1996; Waddell et al., 1999), and it's this
aspect that I'm skeptical about.  But I'm happy to be proved wrong...
by more fossils, not more molecular analyses.





Cheers

Tim





Cheers

Tim