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
closely related.)
That
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".