RE: new _Scleromochlus_ ref

["John R. Hutchinson" <jrhutch@socrates.berkeley.edu>]

At 4:56 PM +1000 9/21/99, Adam Yates wrote:

>I don't have the paper with me but I'm sure it was a stem-based definition
>(ie all taxa closer to birds than to crocs). So it is equivalent to
>Gauthier's Ornithosuchia (and if you adhere to strict priority it is a
>junior synonym) but doesn't have the problem that the higher taxon doesn't
>contain it's nominal taxon.

Yes, Adam is correct (oops, I missed his earlier post on this).  Defines Avesuchia as "a node-based taxon consisting of Avemetatarsalia and Crurotarsi and all their descendants."  Avemetatarsalia = "all avesuchians closer to Dinosauria than to Crocodylia."  (p.1440)

Also mentioned in the paper and of interest to many here (p.1441): "Longisquama... is an archosaur (diapsid temporal region, antorbital fenestra, mandibular fenestra).... Longisquama cannot be assigned more precisely within Archosauria (Unwin et al. 1999): most of the diagnostic characters of Crurotarsi and Ornithodira refer to the hindlimbs, and these are unknown in Longisquama.

Earlier on the same page he argues against the notion that Sharovipteryx is an archosaur, and cite's Unwin et al.'s suggestion that it is a prolacertiform.

The Unwin et al. paper is/was in press in The Age of Dinosaurs in Russia and Mongolia.


--John R. Hutchinson