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Re: Microraptor also ate fish



Don Ohmes <d_ohmes@yahoo.com> wrote:

> Catching an adult bird in a tree, especially a full-on perching bird, which 
> likely will be located
> in the terminal branch environment - that is one heck of a feat.


Indeed.  There's no way that _Microraptor_ could climb out onto a
terminal branch.  If it did climb trees at all, _Microraptor_ would
presumably have been restricted to trunks and thick branches (as
illustrated in Fig. 3 of O'Connor et al. 2011).  It's worth noting
that many contemporary birds, which had an elevated hallux, could
probably not have perched on terminal branches.  For example, I very
much doubt _Confuciusornis_ could have (see below).


> I have never seen a cat even attempt such, though - barring nest robbing. 
> What extant
> animals are cited as analogs?


No analogs, as I recall.  But when it comes to dinosaurs, I'm not so
hooked on modern analogs anyway.  For example, no modern glider shows
incipient flapping ability.  But avialan ancestors and their close
relatives might have included gliders that flapped occasionally while
in the air - such as for steering, or for a bit of extra 'oomph'
(thrust).


Mickey Mortimer <mickey_mortimer111@msn.com> wrote:


> If we're going to go that route, why are we even bothering to compare ungual 
> curvature and
> phalangeal proportions to determine Confuciusornis' habits?  There's 
> obviously some level of
> comparison, and you could come up with features arguing for "my" side just as 
> easily-
> Maybe confuciusornithids' different standing posture, ability to hold on with 
> hands, heavier
> gut if they were herbivorous, longer hallux, assumed non-webbed feet and 
> larger claws etc.,
> etc. counteract the supposed shorter hindlimb and forward center of mass 
> advantages of the
> wood duck.  But if we just say these differences don't allow comparison, we 
> won't get
> anywhere.


No, I'm saying that our comparisons between _Confuciusornis_ and
modern birds should stick to proven adaptations (pedal proportions,
ungual curvatures, etc).  Your scenario has too many 'maybes'.  Saying
_Confuciusornis_ could have behaved like a wood duck strikes me as
special pleading.


In modern birds, an enlarged, incumbent and fully reversed hallux is
indicative of refined perching ability.  _Confuciusornis_ has a hallux
that was quite short, elevated, and not fully reversed (though the
J-shaped metatarsal suggests a caudomedial orientation of the hallux).
Thus, _Confuciusornis_ looks like it has an incipient anisodactyl
perching pes (_Changchengornis_ seems to go one better, with a
relatively longer hallux).  So I suspect confuciusornithids could
perch, and therefore spent some time in trees.  But they were not very
good at perching, and were probably limited to thick branches
(_Confuciusornis_ more so than _Changchengornis_).  But I also suspect
they spent most of their time on the ground, which is in line with the
phalangeal proportions and ungual curvatures you mention.







Cheers

Tim