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Re: Is the Saurischia legitimate?
In a message dated 96-01-01 00:03:14 EST, MMraptor@aol.com writes:
>What defense do modern paleontologists have for the order <Saurischia>? What
>can anyone possibly have to keep the agile, avian, and possibly feathered
>mongoliensis> and such elephantine giants as <Brachiosaurus brancai> and
><Apatosaurus ajax> in a taxonomic relationship as close as that between
>modern dogs and cats? The primitive pelvic structure isn't a good excuse -
>it's a default feature, one that the earliest ancestors of the Dinosauria
>posessed, including that of the <Ornithischia.> It doesn't prove that a
>closer relationship exists between the theropods and the sauropods than
>between either of them and the Ornithischians. The semi-opposable-thumb
>reputedly unique to the <Saurischia,> might not prove much either - In the
>last chapter of his book, <The Dinosaur Heresies,> Bakker states that there
>exists an ornithischian with such a feature, <Heterodontosaurus.> Can
>please tell me if he is right, or if they have found another way to support
>this centuries old classification?
All the characters I've seen that purport to support Saurischia are dubious.
In my book _Mesozoic Meanderings_ #2 (third printing), and in earlier
publications, I argue that Bakker (and Michael Cooper before him) are correct
in insisting that ornithischians should be grouped with brontosaurs (and
segnosaurs) in a clade Phytodinosauria. There is not one feature of
ornithischians that cannot be derived naturaly from a primitive sauropod or
prosauropod. And indeed, that supposedly opposable thumb-claw exists, in
modified form, in many ornithischians.
The other paleontologists will wake up eventually. Give them time.