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re: Tanystropheus neck posture



At 07.44 24/10/02 -0500, you wrote:
>Maybe Tanystropheus wasn't marine.
>
>I just took a look at Wild 1973 and note that in exemplar q,

err.. in Wild 1973 exemplar q is an isolated skull and neck, thus you
probably refer to another specimen, but which one?

Exemplar "q" for the head, "k" for the rest. Good catch.


>Just a wild hypothesis, but what if Tanystropheus fed on arboreal
>diapsids, like longisquamids and basal pterosaurs, by standing at the
>base of trees and searching the boughs for prey?  The clincher is the
>giant penile bones would make great bases for a tripodal posture.
>
>Mmm... the Gerenuk (if I remember the correct name) is an antelope with
a
>long neck that adopts bipedal stance to browse high foliage, keeping
>steady by grappling trees with forelimbs. The posture is a bit awkward
but
>apparently it works. However the main difference is that foliage
doesn't
>rush away when the head come close it is much simpler to pick up also
in a
>static position. a small swift animal is much harder to be catched in
that
>way, I suspect.   Foliage is abundant and you have not to move from a
tree
>to another too often, thus this feeding strategy is rewarding for the
>antelope. A predator should move much more frequently, especially if
>catching a small prey it puts all the neighbours in alarm and they flee

>away. And foliage, small branches etc. may be a serious obstacle to
catch
>those preys. Much better to be small or sneaky for this task.
And don't forget, apparently the clincher or whatever they are, are
present
only in half of larger known specimens...


A good point, Silvio. In my opinion, the only way for this to work is by
stealth. The neck goes up the tree, perhaps extremely slowly, perhaps
angled out at some distance from the tree. If Tany stropheus sees
something, it strikes like a cobra. Perhaps, with its large eyes, it fed
after dusk, when others were settling into nests and hiding  places. Let
the frightened others flee to other trees. Tanystropheus can repeat this
scenario as often as necessary. If this scenario is correct,
Tanystropheus was not a high-energy sprinter, like its smaller cousins,
the longisquamids, langobardisaurs, and pterosaurs, but rather a
slow-moving predator.

Just imagine, after Tanystropheus swallows its prey whole, one might be
able to watch the struggling victim sliding a dozen feet down the
esophagus.

David Peters