[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Reversed Hallux in Theropods: a query

>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)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
Home: 1825 Shady Creek Court                  Messages: (416) 368-4661
Mississauga, Ontario, Canada L5L 3W2          Internet: ornstn@inforamp.net
Office: 130 Adelaide Street W., Suite 1940    
Toronto, Ontario Canada M5H 3P5