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OK. Before anyone mentions lagosuchus and the
like, I should be more specific and askif the dinosaurian line couldn`t be
traced back even further. What Carroll lists as archosauromorph groups are:
Prolacertiformes, Rhynchosaurs., and Trilophosaurs, all shown on pg 264 of his
book, along with a drawing of Euparkeria (which some have determined was
>not< on a direct line to the dinosaurs. So, then, what are the choices? I
see prolacerta as the closest in form to a possible theropod ancestor,
Rhynchosaurs and Trilophosaur seem too specialized. Could Euparkeria be evolved
from prolacertilians? (otherwise,....where did it come from?) Are dinosaurs
considered derived from something else,....(not yet discovered)? I`d just like
to know what the general opinion is on this early aspect of archosaur
evolution.
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