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re: bipedal crocodylomorphs



John Hutchinson wrote:

Does anyone one [know] where the bipedalism idea first comes from, and
what papers
have dealt with it in the most detail?



>>>>

The notion of bipedalism among various diapsids is over 100 years old
and I'm not sure who first coined the idea ? but if you're looking for
analogs and evidence, IMHO, the worst way to answer this question is to
go searching among synapsids (sorry Jaime). They're different in every
way.

Rather, seek those answers among the diapsid taxa that you know are
bipedal and then work backward phylogenetically  to the quads. Between
them try you'll be able to determine what marks them as different
morphologically.

Snyder 1954 did something like this with lizards (testing only quads vs.
the 19 sometimes bipeds) and made a list of the differences (DML
archives also have this list as it's been often repeated).

Do the same with Eoraptor, Sharovipteryx and Scleromochlus, three (how
could they be anything other than) bipedal diapsids. And maybe
Pseudhesperosuchus just for grins.

When you do, I think you'll find the same answer that Snyder found 50
years ago.

A modern look at the subject would be refreshing, since it is my
impression that the earliest notions were just that, notions, without
much substance other than relative limb length and the authority of the
author. I mean, really, what did they have to work with back then?

David Peters
St. Louis

PS Trying to figure out how lizards became snakes (or snake-like) runs
into similar questions, but here one extant genus can sometimes display
the gamut.