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Re: Miragaia's Fancy New Neck....

--- On Wed, 2/25/09, Mark Hallett <marksabercat@yahoo.com> wrote:

> Thanks Tom! Regarding the behavioral speculations so far, my
> vote would be that M's neck was primarily an adaptation
> for sub-canopy arboreal feeding (which means it avoided
> competition with other low browsers and adult sauropods),
> but as I've said before in regard to such
> specializations, we should avoid the assumption that there
> was only one benefit, like the old arguments about
> neoceratopsian horns being "just" for theropod
> defense or "just" for intraspecific fighting.

Very true. We should likewise avoid the assumption that a "benefit" is 
necessarily a driver of morphological evolution. In this case, it appears 
obvious that any predation avoidance benefit of being long-necked accrues 
_after_ the neck has lengthened significantly, even when constructing 
interspecific scenarios.

Therefore, unless one postulates extreme variation in neck length in the 
population under selection, predation avoidance enhancement may serve to 
preserve 'long-nekked-ness' :D, but cannot act as a driver of incremental 
length increase.

Unless, of course, it can be shown that a difference of a couple of centimeters 
can allow a putative longer-necked animal significantly more time to take 
evasive action...