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Re: Ceratonykus braincase described



David Marjanovic <david.marjanovic@gmx.at> wrote:

> Well, apparently time travel comes in a package with faster-than-light
> travel.

Hmmm.... but Doctor Who makes it look SO easy.



> Extant myrmecophages are not cursorial. They stand and fight and/or climb
> and/or burrow and/or rely on armor or spines. They don't need to notice
> predators in advance -- or, as long as the armor holds, at all.


Extant myrmecophages are not cursorial, because the energy derived
from a myrmecophagous diet does not permit high metabolic rates in
mammals higher than 1 kg mass (McNab, 1984; J. Zool. Lond. 203:
485-510).  Termites have higher calorific value than ants, but still
not great.


> Regarding alvarezsaur arms, I have yet to catch up with the discussion, but
> the combination of proportionally tiny size (in parvicursorines -- not in
> *Patagopteryx* or *Haplocheirus*!), proportionally huge thumb claw, very
> restricted range of movement, and mind-blowing humongous muscle attachment
> sites leads me to support Longrich's hypothesis that alvarezsaur arms
> sacrificed speed and range of movement for power. The extremely long,
> energy-efficient legs and the unusually long, flexible neck made it possible
> to step in, crack something open, step back if necessary, and lick the
> termites up. The weak jaws and tiny teeth fit this. To me, the unique
> combination of traits in alvarezsaurs isn't more mysterious than Coombs's
> chimera: http://svpow.wordpress.com/2011/04/07/coombss-chimaera/

(For _Patagopteryx_ read _Patagonykus_... these two and _Patagornis_
are easily confused)


If alvarezsaurs were myrmecophagous, I doubt that ants and termites
were their ONLY source of food - for the reasons given above.  They
may in fact have been a relatively minor component of alvarezsaur
dietary habits.




Cheers

Tim