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Re: Quo vadis, T. rex? [long]
On Fri, 9 Feb 1996 Dinogeorge@aol.com wrote:
> In a message dated 96-02-09 02:14:07 EST, pharrinj@PLU.edu (Nicholas J.
> Pharris) writes:
> >Why would this be of any more use to ornithologists than anyone else? It
> >would not be productive for primatologists to go around saying that
> >primates are different enough from other mammals to deserve their own
> >coordinate taxon.
> That's because primates are not different enough from other mammals to
> deserve their own coordinate taxon. But mammals are different enough from
> reptiles to deserve their own coordinate taxon.
If you mean "reptiles" in the sense of all descendants of the commn
ancestor of turtles and crocodiles, then no, mammals are not a part of
that taxon, because we are not descended from that common ancestor. If by
"reptile" you mean "an amniote that is not a mammal or a bird," then
Pelycosaurs and therapsids are theropsids. "Pelycosaur" is an informal
term for those theropsids which are not therapsids. Mammalia is the
clade containing all descendants of the last common ancestor of
_Ornithorhynchus_, say, and _Homo_. This taxon can also be defined as
those therapsids which have a jaw joint between the dentary and squamosal
Pacific Lutheran University
Tacoma, WA 98447
"If you can't convince them, confuse them." -- Harry S. Truman