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Re: Microraptor also ate fish



Mickey Mortimer <mickey_mortimer111@msn.com> wrote:


> I never said Microraptor couldn't or didn't hunt, just that no food item in 
> its stomach could ever
> support this over scavenging in any particular case.  Thus no ingested food 
> item could support
> a particular behavior for Microraptor, be it climbing or catching fish.


An ingested food item can corroborate an ecomorphogical hypothesis.
_Microraptor_ has been interpreted as a climbing animal.  When an
arboreal bird turned up in its abdominal cavity, this discovery was
consistent with that interpretation.  The discovery of fish remains is
consistent with _Microraptor_ hunting aquatic prey as well.  I think
this interpretation is more parsimonious than scavenging, based on the
behavior of many modern predatory mammals and birds.


> Enants and Confuciusornis have similar pedal claw angles (Glen and Bennett, 
> 2007), which
> could equally fall into ground-dwelling or perching birds (Pike and Maitland, 
> 2004- fig. 4).


Enantiornitheans typically have superb perching adaptations, including
a hallux that was large and fully descended.  This argues against them
being ground-dwelling birds - though they certainly might have foraged
on the ground.  _Confuciusornis_ has a shorter and elevated hallux.
(The degree of caudal/posterior orientation of the hallux may have
been comparable, depending on the enantiornithean in question.)  The
pedal morphology of _Confuciusornis_ indicates it was likely a
ground-dwelling (terrestrial) bird, but one that might have perched
and possibly sheltered in trees.


Yes, claw angles indicate ground-foraging by _Confuciusornis_ and by
the enantiornithean taxa examined by Glen and Bennett (2007).
However, based on pedal proportions (especially of the hallux),
enantiornitheans appear to have spent far more time in trees than
_Confuciusornis_ did.  I agree with you that _Confuciusornis_ could
climb trunks using its large, clawed hands, in lieu of an inability to
execute a ground-level take-off.







Cheers

Tim