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Re: Segregated chop demons repaired...



What I get for messing around, I guess.

Replacing chopped text -- 

"And they are also very tightly packed, relative to assumed track diameter.

So, as John B. says -- "... very careful egg laying in broad daylight!" 
Although I am not at all sure about the need for daylight.

Anyhow, The speculation that head-size was constrained by reproduction in the 
mega-sauropods doesn't seem implausible to me. Or testable."

--- On Mon, 3/15/10, don ohmes <d_ohmes@yahoo.com> wrote:

> From: don ohmes <d_ohmes@yahoo.com>
> Subject: Re: Segregated vs age-mixed sauropod herds
> To: dinosaur@usc.edu
> Date: Monday, March 15, 2010, 8:56 PM
> --- On Mon, 3/15/10, don ohmes <d_ohmes@yahoo.com>
> wrote:
>  
> > "Finally, although nest attendance may be inferred by
> > phylogenetic bracketing (all living archosaurs attend
> their
> > nests), the large size of adult
> > titanosaurians and the proximity between egg-clutches
> > suggests little or no parental
> > care, an inference consistent with the absence of
> evidence
> > of trampling." -- from Chiappe,  
> > 
> > <http://dinosaurs.nhm.org/staff/pdf/2005Chiappe_et_al-Paleovertebrata.pdf>
> > 
> > Chiappe does not address the case where the nests are
> in
> > 'patches' w/ an effective radius of <1 neck length,
> which
> > would allow direct tending /w the mouth, perhaps even
> by a
> > single sentry. 
> > 
> > Implied by such close proximity is 'turn-taking' in
> terms
> > of nest-building, and nest locations that are closely
> > defined by the previous nesters. Which in turn
> implies
> > social order, perhaps hierarchy, and keen instinctual
> > awareness and avoidance of the nests of others. Quite
> > remarkable, IMO, "nest attendance" or not...
> 
> Visualizing the nesting process, again assuming the rookery
> scenario is correct: once a multi-nest 'patch' was been
> established, how does a female ready to lay her eggs add her
> nest to it? 
> 
> "Building" a depression with the head from a safe distance
> seems straight-forward; but then this huge animal had to
> turn, put hers
everse gear, and position herself
> over the depression, keeping the tail clear of the ground to
> avoid disturbing other nests, and deposit the eggs with
> reasonable accuracy into it. Perhaps the mouth was then used
> to place any misdirected eggs into the depression as the
> site seems to speak against any scattering of eggs.
> 
> In the counter-intuitive case where the depression is built
> with the large feet, accuracy is still an issue, and the
> head would likely be needed to remedy any poorly-aimed eggs.
> These depressions were very small (=<1m in diameter?)
> relative to the size of the animal, unlike a turtle nest,
> wherein a miss is mechanically unlikely. And they are also
> very tightly packed, relative t
> areful egg laying in broad daylight!" Although I am not at
> all sure about the need for daylight.
> 
> Anyhow, The speculation that head-size was constrained by
> reproduction in the mega-sauropods doesn't seem implausible
> to me. Or testable.
> 
> Are there other, less "demanding" interpretations of the
> Auca Mahuevo site? Any experts out there have an accurate
> idea of the distance between the nests expressed in track
> diameter?
>