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Re: pterosaur femora sprawl
----- Original Message ----
> From: John Conway <email@example.com>
> Which first pterosaurs? No pterosaurs (and I mean _none_) had a
> shoulder-knuckle length less then their hip-ankle length.
True. But no pterosaurs walked, bipedally or quadrupedally, with a horizontal
backbone. Elevate the spine at the shoulders and voila. MPUM 6009 is still
derived in many regards, so it is the most basal _known_ pterosaur.
> > Certainly Anhanguera had a different launch mechanism, with the
> > largest forelimbs and smallest hind limbs and feet in pterosaurland.
> No--/Anhanguera/'s forelimb to hindlimb ratio is on the high side (5.1),
> but no where near /Nyctosaurus/ (6.6, the champ) or /Rhamphorhynchus/
> (6.2-6.4). /Campylognathioides/ is higher at 5 to 5.6. It's similar to
> /Pteranodon/(4.9). /Eudimorphodon/, /Raeticodactylus/, and
> /Pterorynchus/ have a ratio only slightly lower at ~4.5.
True. I had Arthurdactylus in my mind's eye when I wrote Anhanguera. And you
are so right about certain Nyctosaurus, Rhamphorhynchus and Campylognathoides.
In any case the point is relative mass or bulk -- not length -- although length
is more readily measureable and certainly, as you point out, a factor. The
pelvis, hindlimb and feet of ornithocheirids are so small they are dwarfed, in
comparison, by the bulk of the wings, despite their length.
> >> we know they walked quadrupedally,
> > The beachcombing taxa, yes. No prints yet for the soarers, skimmers,
> > insect-eaters, basal forms.
> Which taxa do you think were soarers and skimmers? Because /Pteranodon/,
> /Nyctosaurus/, anhanguarids (soarers), /Jeholopterus/
> (insect-eater/basal) /Raeticodactylus/ and /Eudimorphodon/ (basal), have
> comparatively small legs. Odd adaptation for bipedalism.
All pterosaurs except "azhdarchids," ctenochasmatids, dorygnathids (that's one
clade) and cycnorhamphids + ornithocheirids (a second clade).
re: Odd adaptation for bipedalism:
Don't forget the albatross and the hummingbird (comparatively small legs).
Case closed? : )
Best to you, John. David
> Palaeontography: http://palaeo.jconway.co.uk