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Vestigial Arms != Big Jaws (Was: Theropod limbs - how mobile?)
> Date: Thu, 16 May 2002 08:38:27 +0200
> From: "Fam Jansma" <email@example.com>
> Large theropod evolution, wether you are talking about Carnosaurs or
> Tyrannosaurs, seems to be focussing one increase in body size and
> decrease the size of the forelimbs (Giganotosaurus in the
> Carnosaurs, Tyrannosaurs in general).
... so that more mass can go into the head and particularly the jaws,
yes. That's what I assumed. Makes perfect sense.
The fly in this particular ointment, to my mind, is _Carnotaurus_.
This critter has ludicrously attenuated forearms -- I mean, it makes
_T. rex_ look like _Deinocheirus_. Yet its head is also relatively
puny: it has one of the shortest heads (relatively) of all theropods.
And worse, it has a long trunk and neck. All that precious body-mass
wasted when it could have gone into the jaws!
Illustrative skeletal reconstructions at
and a full-flesh rexstoration at
if you prefer that kind of thing.
So I think the simple smaller-arms-for-a-bigger-head model,
intuitively appealing though it appears, is flawed.
/o ) \/ Mike Taylor <firstname.lastname@example.org> www.miketaylor.org.uk
)_v__/\ "Too many people on the bus from the airport, too many
holes in the crust of the earth: the planet groans every
time it registers another birth" -- Paul Simon, "Born at
the Right Time"