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Re: Mammal - Like - Reptiles ... info needed.
Dave, in a message dated 98-02-23 01:03:40 EST, wrote:
<< I would definitely recommend John McLoughlin's book _Synapsida_, which is
regretably out-of-print, but should be at a local library.>>
There is of course _The Ecology and Biology of the Mammal-like Reptiles_
edited by Nicholas Hotton III and published by Smithsonian Institution Press,
but it is hard to get and very expensive (and even now just a tad dated.).
<<I consider myself
a Therapsid-advocate, and I too would like to know if there are any web pages
or other recent reference sources devoted to them. I think the Therapsids
have gotten short shrift to tell you the truth. They may not be as
imagination-capturing as the Dinosaurs, but they *are* our ancestors and
deserve media attention.>>
Oh, I think that they are certainly as imagination-capturing as the dinosaurs
(oops, shouldn't have said that. Forgive me, oh dinosaur list-folk!) And on
therapsid web sites, currently being constructed is my web site devoted
entirely to the nonmammalian Therapsida. When complete it will have pics,
phylogenies, and a whole lot of info on the eotheriodonts, dinocephalians,
anomodonts, and theriodonts.
<And while we are on the subject, what is the current status of the
Are they a distinct Therapsid suborder, or are they considered part of
group like the Dicynodonts? I know not much is known about the Dromasaurs,
but I thought maybe someone had some new insights...>>
They are, no, I should say were, a very problematic little group of critters.
The Dromasaurian Threesome--Galeops, Galepus, and Galechirus, were once
thought to have split off from basal herbivorous therapsids before the
dinocephalians (Romer). From time to time it was recognized that they shared
features with the dicynodonts and the venyukovioids, and because of their
large eye sockets and small size were considered juveniles of another animal.
They have recently been reanalyzed and recognized as a paraphyletic assemblage
of animals becoming more and more dicynodontian. The taxa "Dromasauria" and
"Venyukovioidea [=Venyukoviamorpha]" have been discarded as they are para and
polyphyletic (and good riddance. One has a spelling that constantly proves to
be confusing and the other is too often mistaken to be Dromaeosauria). The
former members of all these groups are considered basal anomodonts, the group
including the dicynodonts. The finding of Patranomodon (a rather complete
specimen which told much about "dromasaur" anatomy), the most primitive
anomodont, has suggested that Galepus and Galechirus are at the most primitive
grade (and they may form a group with Patranomodon--it would be the
Galechiridae), and it has been demonstrated that Galeops is actually a form
more advanced than even the Russian Otsheria. Does that clear everything up?
These references deal with the dromasaur problem extensively:
Brinkman, D. 1981. The structure and relationships of the dromasaurs
(Reptilia: Therapsida). Breviora, Museum of Comparative Zoology. 465, 1-34.
Rubidge, Bruce S. and James A. Hopson. 1990. A new anomodont therapsid from
South Africa and its bearing on the ancestry of Dicynodontia. South African
Journal of Science, 86:43-45.
Rubidge, Bruce S. and James A. Hopson. 1996. A primitive anomodont therapsid
from the base of the Beaufort Group (Upper Permian) of South Africa.
Zoological Journal of the Linnaean Society. 117: 115-139.