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Re: Rapator,the giant alvarezsaur
Dann Pigdon wrote:
I like to imagine giant alvarezsaurids like huge Maribu storks (or
Australia's Jabiru stork, with a confusingly similar name). Perhaps
alvarezsaurids started off large, mainly using sharp stabbing beaks (or
proto-beak structures), during which their forelimbs atrophied (similar
to what may have happened in tyrannosaurs).
So the enlargement of the claw and strengthening of the forelimb musculature
came *after* the forelimbs were downsized? This hypothesis sounds similar
to what transpired in the flightless bird _Titanis walleri_, which had tiny
but apparently functional forelimbs tipped by a moveable claw.
Later, if conditions
favoured smaller alvarezsaurs, their forelimbs may have evolved into as
functional a set of tools as was possible, given what they had to work
But what was this "function"? If the forelimbs did regain function after a
period of atrophication, why did they remain so small?
to place a lot of emphasis on their forelimbs alone, as if their entire
behavioural repatoir must have accounted for them. They had other body
parts as well...
True, but the forelimbs represent the most apomorphic part of the
alvarezsaurid anatomy. The stubby forelimbs tipped by a single claw are
highly specialized, and contrast with the gracile, cursorial proportions of
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