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Prehensile Tails



To the List et al.,

  Not to rehash what appeared previously on the list
last year but got relatively little coverage here
(don't know about offlist). There was some question on
the prehensile tails of proposed bird ancestors like
the Megalancosauridae or *Cosesaurus*, and what
morphological features would pertain to prehensility.
Recently, I have had the opportunity to observe
whales, rats, monkeys, and theropods to determine the
flexibility of their tails in this respect, but at am
an impasse without delving into literature that, aside
from the more popular mainstream journals to which
references I do not have, the exact morphological
features associated with prehensile tails.

  However, the prehensile tails of rats (marginal,
anyway) and monkeys (some) have a lack of overlapping
zygaophyses, long caudal centra, and either very short
or absent chevron bones. Is this so with whales, and
does this occur in chameleons? It might help. Giraffe
necks, I've found, do not compare because they possess
developed zygapophyses and the only movements possible
in giraffe necks appear to be a lot of lateral but
little dorsal or ventral movements.

  Some theropods have elongate caudal centra, but lack
the other features I've noted, and in coelurosaurs at
least, have very elongate zygapophyses and long
chevrons (dromaeosaurs are one extreme example of the
first type, and oviraptorosaurs of the second).

  Ol' country boy just wonderin',

===
- Greek proverb: "Knowledge is Inherent;
  Stupidity is Learned." -

Jaime A. Headden

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