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Re: [dinosaur] 2016 in paleontology + Dippy's last days in London + burrows around Omeisaurus + more
> David Černý <email@example.com> wrote:
>> (Mayr 2016) accepts and reiterates
>> Senter's (2006) conclusion that flapping flight was biomechanically
>> impossible for early birds, mentions "[t]he physical and biological
>> implausibility of a strict 'ground-up' origin of flight" (p. 39), and
>> presents a stationary leaping take-off as a highly derived locomotory mode
>> associated with a complex of pectoral girdle and wing adaptations that is
>> unique to a couple of deeply nested neornithine lineages.
The Mayr (2016) argument here perplexes me a bit; I may be missing something.
In living birds, running takeoff is a mostly a derived feature of water birds,
and I cannot find a parsimonious way to map it onto any recent phylogeny that
avoids multiple derivations. In other words, running takeoff seems to be
derived, at least within the crown group.
I'm also not clear (I'll have to go read the work in detail) why Mayr has such
a focus on wing characters for stationary leaping launch, since launch mode is
mostly dependent on hind limb morphology and substrate. Wing characters
influence climb out, but not running vs leaping launch mode preference.
> Mayr (2016) is highly skeptical of any scenario for the origin of
> flight that that doesn't involve a "gravity-assisted" gliding stage.
The weird thing here, for me, is that living arboreal flyers still use leaping
launch modes to initiate flight - even the unpowered ones. There are no living
gravity launchers (that we have found so far, anyway). So even if Mayr had good
evidence for arboreal behavior near the origin of avian flight, I'm not sure
how that would yield a "gravity assisted" model. I suppose he's referring to
the gliding phase itself?