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RE: Microraptor also ate fish

Mickey has been indefatigable here in reminding us all that UNCERTAINTY must be 
respected in science. We must not overinterpret our evidence, and we must 
remember that even the best - supported hypothesis can still be proven wrong in 
an instant by new discoveries. Though it may be a bummer to say "we don't 
know", if we stop saying that then we are letting speculation get the best of 

Let's consider the proposal that there is no way that Microraptor could climb 
onto a terminal branch. Ravens, Corvus corax, weigh about 1.2 kg, about the 
same as some specimens of Microraptor. Here are photographs of ravens perching 
on tiny terminal twigs without difficulty:




We all know that ravens have fully developed halluces, but uncertainty exists 
about the possible gripping function of Microraptor's second toe and the 
function of manual claws in stabilizing climbing. 

Therefore it may be HARDER for Microraptor to do so, but I would not be 
comfortable saying there is NO way. Indeed, any gliding ability may have been 
Microraptor's ultimate safety margin should it try to achieve a risky perch and 
fall. Has anyone seen fledgling birds smash into sprays of thin twigs and 
manage to land there thanks only to flinging their wings out flat? I have.

Uncertainty is a high principle, everyone.

From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Tim Williams 
Sent: Tuesday, April 23, 2013 4:41 AM
To: dinosaur@usc.edu
Subject: 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 on

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'

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.  _
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.