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Re: _Eomaia_ and dung-eating vultures...
At 10:28 AM +0200 4/28/02, David Marjanovic wrote:
While doing some housecleaning, I came across a paper by Michael
Novacek et al in the 2 October 1997 Nature (V. 389, p. 483) titled
"Epipubic bones in eutherian mammals from the Late Cretaceous of
Mongolia" which reports "the first record of epipubic bones in two
distinct eutherian lineages, dating from 75 million years ago.
Is one of them *Ukhaatherium*, or is that yet another paper? In the *Eomaia*
paper *Ukhaatherium* comes out closer to us than (to) *Eomaia*, with all
other included Mongolian eutherians as its sister groups (polytomy). It has
long been considered probable that one of those, *Zalambdalestes*, retained
epipubes, too; has one been found meanwhile? (Would IMHO provide strong
evidence against the recent idea that Zalambdalestidae and Glires are
The species named in the Novacek paper is Ukhaatherium. It says that
in the skeletons they collected in Mongoliam, "Skeletons of two
eutherian taxa preserve epipubic bones, a zalamdbalestid (c.f.
*Zalambdalestes*) and a new taxon of insectivore-like eutherian
closely related to the previously described Asioryctes. The new
taxon, Ukhaatherium nessovi" is what they describe. The original
reference to the zalambdalestid is from 1926, an earlier expedition
raises some interesting evolutionary questions, and implies a
potentially significant chunk of the phylogentic tree of eutherians
between Eomaia and true placentals has gone extinct.
Maybe not so much. They say *Gypsonictops* is a leptictidian (at last I find
that somewhere), and it comes out fairly basal, just 2 nodes closer to us.
Too bad, though, that they didn't include more Cenozoic placentals, and that
they don't cite the SVP meeting abstract that finds Zhelestidae close to
Zalambdalestidae instead of close to Artiodactyla or something else Cenozoic
(represented by *Protungulatum* in their analysis). Too bad most of them are
"the tooth, the whole tooth, and nothing but the tooth".
The lack of skeletal material is obviously a big problem. I'd really
like to see some more mammals from the Yixian deposits. As with
dinosaurs, a few really well preserved fossils can explain a
Speaking as a science writer, this is a potent reminder to be careful
when simplifying descriptions. Terms like "eutherian" have to be
explained to the general reader, but it isn't right to call Eomaia a
And now I'll read the Supplementary Information. Or not (it has 162 pages).
I just see the paper was first submitted on November 18, 2001... they're
very good at keeping things secret; that gives much hope what else might be
published soon from Liaoning. :-9
The supplementary information includes the listing of the 268
characters used to derive the phylogenetic tree, the references, and
the trees. -- Jeff Hecht