Re: Reversed Hallux in Theropods: a query

[ornstn@inforamp.net (Ronald Orenstein)]

>The alternative is the BADD theory, in which the hallux loses its proximal
>end, shrinks, retroverts for no evident reason to a quite specific site on
>the back of metatarsal II, and then sits there with a dangling digit for
>about 35 million years on almost every known theropod from ceratosaurians to
>tyrannosaurians awaiting future use as a perching organ in the one theropod
>lineage that evolved into birds.
>

Except for the last 16 words this appears to me no more unlikely than the
retention of cannon bones in horses, internal hind limb elements in
cetaceans or a number of other vestigial structures that have apparently
hung around for a long time in certain forms.  And of course this is not the
only alternative - the other alternative is that in these animals the hallux
retained some minor function, whatever that might have been, consistent with
a terrestrial existence.
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
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