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Re: Hopping Maniraptors



Waylon Rowley <whte_rbt_obj@yahoo.com> wrote:

<After looking at some of the long-legged maniraptors coming out of China
recently, I've been wondering whether it was possible for them to hop like
a kangaroo rat. Are there any morphological indicators that dispell or
cast doubt on such an idea?>

  There are several morphological characters found in saltators and
richochetors [animals that bound with both legs together, and only by the
hind legs, with a gait pattern that is quite defined]:

  1) an elongate calcaneal tuber

  2) an elongate meta (ankle) and propodium (metatarsus and distal
tarsals)

  3) shortened pedal phalanges that work as a single structure unit under
tension

  4) a short femoral arm

  5) an elongate femoral retractor moment, one that is attached to a
caudally expansive innominate (puboischiadic part).

  These are the features used in mammals that are implicitly important for
hopping and ricocheting. Reptiles with calcaneal tubers do not have any of
the other features, despite short forelegs, and this is suggestive only of
partial or complete bipdeality; they were likely obligate bipeds.

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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