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Re: Regarding Phytodinosauria, Saurischia, and so forth

In a message dated 95-08-13 16:19:49 EDT, jdharris@lust.isem.smu.edu (Jerry
D. Harris) writes:

> I personally don't find it nearly as likely that this
>animal -- or therizinosauroids -- are relics from the Triassic that have no
>fossil record whatsoever until the Cretaceous as they are reversals of the
>shrunken condition.

If segnosaurs remained small animals (less than 1 meter long) throughout the
Jurassic, their fossil record could well be nonexistent.

If you're going to derive the segnosaur foot as a reversal from the theropod
condition, you must explain how and why (1) metatarsal I re-enlarged; (2)
metatarsal I moved from its articulation point at the back of metatarsal II
to realign almost exactly parallel alongside the other three metatarsals; and
(3) metatarsal I reacquired a proximal enlargement that rearticulated with
the tarsus, long lost in the theropod foot. That's a pretty intelligent
metatarsal I(!).