Re: smallest ANCIENT non-bird dinosaur - was what I was asking

["T. Michael Keesey" <keesey@gmail.com>]

On Thu, May 1, 2008 at 6:37 AM, David Marjanovic
<david.marjanovic@gmx.at> wrote:
>
> > so, does Microraptor still rule?
> >
>
>  If you cut off the birds, yes. How much sense that makes is anyone's guess,
> though; it's not even clear if *Microraptor* was flightless.

Exactly -- it depends on what you mean by "bird". If you use it to
mean anything closer to modern birds than _Microraptor_ is, then, yes,
it might still be the smallest. That's kind of loading the dice,
though.

If you used it to mean "feathered dinosaur", then _Microraptor_ is a bird.

If you use it to mean "avialan" (i.e., the first ancestor of modern
birds to possess powered flight homologous with that of modern birds
and all descendants thereof),  then it's not clear whether or not
_Microraptor_ is a bird.

If you use it for the _Archaeopteryx_ + modern birds node, then it's
still not clear whether _Microraptor_ is a bird or not. It probably
isn't, but there may be some other tiny, winged forms which also are
not.

If you use it for the crown group, then it's definitely not a bird,
but there are many Mesozoic non-birds smaller than _Microraptor_.

(BTW, under any usage of "bird", all non-bird dinosaurs are ancient.)

I suppose you can say this about _Microraptor_: it's the smallest
dinosaur that's at least as close to the avian crown group as it
itself is. Probably.
-- 
T. Michael Keesey
Director of Technology
Exopolis, Inc.
2894 Rowena Avenue Ste. B
Los Angeles, California 90039
http://exopolis.com/
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