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Re: Microraptor also ate fish

Mickey Mortimer <mickey_mortimer111@msn.com> wrote:

> Equally possible but also equally likely to be due to scavenging in both 
> cases, yes.

I tend to think that hunting a diverse array of prey was well within
the abilities of _Microraptor_. Yes, it is possible that _Microraptor_
scavenged.  But _Microraptor_ was certainly adapted for a predatory
lifestyle.  So when a small fish/bird/mammal ends up in its stomach,
I'm going to give _Microraptor_ some credit and assume that it could
hunt its own prey.  And "prey" includes fish and arboreal birds, as
well as small mammals.

> Then he points out Sinocalliopteryx also ate birds and was near certainly not 
> arboreal.  All of
> this would seem to nullify much of the impact of the paper.

I disagree.  The situations (_Sinocalliopteryx_ vs bird /
_Microraptor_ vs bird) are not quite the same - because the birds in
each case are very different.  The bird eaten by _Sinocalliopteryx_
was a _Confuciusornis_, which has a morphology consistent with it
being terrestrial (although the morphology also suggests it spent some
time in trees, and possibly even perched).

On the other hand, the bird eaten by _Microraptor_ was an
enantiornithean, and Jehol enantiornitheans tend to be arboreal.  So
given the respective lifestyles of the birds, one could argue (and I
am) that the _Confucusornis_ was more likely to be caught on the
ground than in the trees. Conversely, the enantiornithean was more
likely to be caught in trees than on the ground.

> I hate to use the term misleading, but the abstract states "Several 
> morphological adaptations of
> Microraptor are identified as consistent with a partially piscivorous diet, 
> including dentition with
> reduced serrations and forward projecting teeth on the anterior of the 
> dentary."  Is this really
> right to say when the paper identifies only these two characters as 
> indicating piscivory?  "Two
> (which does not mean several) adaptations are identified, including these 
> two"?

Well, two is better than none at all - even if those two characters
have a wide distribution among maniraptorans.  I get what you're
saying here Mickey: Are we reading too much into the available
evidence?  Nevertheless, we do have a small predatory theropod with a
fish inside it.  Is it such a leap of faith to posit that the theropod
caught the prey alive, and (therefore) that it was a versatile and
opportunistic hunter?  I think this is a reasonable hypothesis.

_Microraptor_ seems to have scansorial abilities, although I dispute
that it was arboreal (i.e., spent most of its time in trees).  But
_Microraptor_ didn't need to have arboreal adaptations in order to
hunt prey in trees.  Similarly, _Microraptor_ didn't need aquatic
adaptations in order to hunt prey in the water.

Again, I'm prepared to accept the hypothesis on offer: That
_Microraptor_ was an opportunistic and generalist hunter that targeted
prey on the ground, in the trees, and in shallow water.  I hold this
hypothesis as more likely than the alternative: That _Microraptor_ was
limited to terrestrial prey, and any arboreal or aquatic animals it
ate were the result of scavenging.  This seems unnecessarily