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RE: Ceratonykus braincase described



  On an ecological note, predator-prone myrmecophages exist that are not 
defensive fighters. They have to watch out for a different type of predator, 
one that trumps jaguars and anteaters from South America: Snakes and various 
eagles predate the Madagascan-African "myrmecophages" [I'm using this term 
loosely here, they are generalist insectivores as well] principally because one 
method they used to escape ground-based predators (presumably where 
alvarezsaurs are constrained) is to climb trees. But they are not the 
"exclusive" myrmecophages spoken of below, but then nor are some 
defensive-fighter "myrmecophages," such as the tamandua.

  I would contend, as with many herbivorous-or-not arboreal animals, any any 
that takes to the trees will require a compliment of increased sensory 
capabilities in the optic and potentially auditory regions of the brain as well 
as large sense organs to make do with having to deal to increased range of 
attention (it has to care about what is below it now, as well). Ground-based 
myrmecophages (really, not that many of them) have large ears, but very small 
eyes, but incredible senses of smell: see the aardvark and greater anteater. 
These senses make up for the lack of high cursoriality or evasive abilities, or 
the ability to move in a third axis. So why the humongous eyes of alvarezsaurs, 
but apparently middling olfaction?

Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)





----------------------------------------
> Date: Thu, 28 Apr 2011 11:33:49 +0200
> From: david.marjanovic@gmx.at
> To: dinosaur@usc.edu
> Subject: Re: Ceratonykus braincase described
>
> > What's the point of even having physicists if they can't develop
> > something as simple as time travel? :-)
>
> Well, apparently time travel comes in a package with faster-than-light
> travel.
>
> But to return to the topic... Alvarezsaurs evidently dealt with
> predators by running away. This required sensing the predators early
> enough that running away was still possible. Good eyesight and hearing
> had to be expected just from looking at the proportions of these animals.
>
> 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.
>
> 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/