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Re: Theropod infanticide -- speculations



Stephan Pickering (StephanPickering@cs.com) wrote:

<Moreover, one can ask if field notes on the Ghost Ranch Coelophysis can
show distribution of females within the colony, the colony itself being a
theropod breeding strategy (females suppressing their own breeding to
co-parent offspring of dominant females).  Multiple mating > confusion
among males as to paternity of altricial nestlings, as pregnant female
theropods would mate with "strange" conspecifics. Could it be female
Coelophysis had multiple matings when infanticide was a real possibility,
the MMs decreasing if infanticide was a remote possiblity?  This leaves a
possible question: the Ghost Ranch ensemble of several animals may be
evidence of a large infanticide intrusion vs. accidental death of so many
theropods.>

  This would be interesting if we could only find out which of the
dimoprhic forms (gracile vs. robust) were indicative of a gender, could
prove it indicates a gender, could prove there were only two morphs, and
that any reasonable information could be gleaned from this. Data from
Colbert and Raath indicate that only in the largest forsm do the primary
features diagnostic of their use of dimorphism in ceratosaurs actually
appear in full force. Younger "robust" forms look a lot like older
"gracile" forms, and this confuses the issue.

  It's all nice and dandy to have that data, and  then have to prove that
1) extant bird and mammal ecologies have anything to do with fossil
dinosaur ecologies, 2) that cannibalism actually took place in
*Coelophysis*, 3) and provide a reasonable hypothesis to the nature of the
Ghost Ranch *Coelophysis* bone bed, which may or may not be cataclysmic,
and thus have little to do with herd structure, etc.

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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