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Re: Archaeopteryx flight
David Marjanovic wrote (quoting Greg Paul's PDW):
We have already seen how the conical teeth of some small
theropods were suitable for fishing. In fact, the very conical, unserrated,
and big-rooted teeth of *Archaeopteryx* are most like those of marine
crocodilians, whales, and the toothed diving bird *Hesperornis*.
This would put _Archaeopteryx_ in direct competition with the
rhamphorhynchids. The latter had jaws and teeth specialized for piscivory,
including procumbent teeth at the front of the jaws. The rhamphorhynchids
may also have been superior fliers.
Perhaps there was enough fish to share around. But I like the idea that
_Archaepteryx_ was a more generalized and opportunistic carnivore, with
fish, insects, small vertebrates, and carrion all comprising a part of its
that, but the hooked and laterally flattened claws, especially those of the
hands, are strikingly like the toe claws of fish-eating bats (Figure 9-4)
I know the morphology of _Archaeopteryx_'s manus has diverged very little
from that of ground-dwelling predatory maniraptorans. However, continued
use of the manus in any sort of predatory or scavenging activity risked
fouling the wing feathers which, even at this early stage of avian
evolution, were no doubt integral to the ecology of _Archaeopteryx_. I
think by the stage of avian evolution exemplified by _Archaeopteryx_, the
forelimb and manus may have been largely decoupled from the theropod's
trophic or predatory behavior.
[which shows that the claw curvatures are very similar indeed, a bit more
with Archie's hand claws than with its foot claws].
As with the enhanced perching abilities ascribed to _Archaeopteryx_'s pes by
Feduccia, claw curvature gets you only half the way: the pedal claws have to
be able to meet in order to grasp effectively. The pedal digits of
_Archaeopteryx_ show little opposability - though the reversed and more
distal hallux (also described for _Microraptor_) shows a trend in this
direction. This, and the rather weakly developed flexor tubercles of the
pedal digits, makes the foot of _Archaeopteryx_ a rather poor prehensile
device - and therefore poorly adapted either for perching or seizing prey.
(I am aware that certain people, including one or two on this list, might
disagree with the latter interpretation, and that there is work in progress
on this very topic.)
*** Any evidence of water near *Rahonavis*? That said, it has a joint
between the scapula and the coracoid, so it was a much better flier and
surely not bound to swimming.
David, I don't think Greg Paul is claiming that _Archaeopteryx_ was "bound
to swimming", only that swimming formed *part* of its behavioral repertoire.
Just like the hoatzin, which is capable of a lot of weird stuff, as both
juveniles and adults.
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