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Re: Paper on drepanosaurids
Silvio Renesto wrote:
Simiosauria sounds appropriate, in fact if they are really so basal, they
mimic very well lots of characters of more advanced diapsids, pterosaurs
And birds too! But all of these bird-like ("avimorph") characters appear to
be superficial, such as the triangular bird-like head. Wouldn't it be funny
if _Protoavis_ (or part of _Protoavis_) ended up in the Avicephala?
More seriously, an applause to Phil Senter for stating that no
drepanosaurid is aquatic, something I stated since 1994, but few believed
I can't begin to guess.
Perhaps some more people will now consider it as feasible.
Colbert and Olsen (2001) were so convinced that their new drepanosaurid from
New Jersey was aquatic that they named it _Hypuronector limnaios_ ("deep
tailed swimmer from the lake"). However, the authors did support the idea
that other drepanosaurids may have been arboreal:
"_Hypuronector_ has a very deep tail, superficially comparable in shape to
that of gymnotid or gymarchid fishes (figs. 6, 15 ). No other tetrapod has
such elongate chevrons, or a tail with a strongly similar structure. The
similarity at least superficially to the deepened tails in aquatic tetrapods
such as newts and crocodilians, however, strongly suggests that the tail of
_Hypuronector_ was adapted for sculling in water. [snip] There is no
evidence that _Hypuronector_ could lift its tail so that it was at an acute
angle to the dorsal series; all of the articulated specimens found thus far
have the caudal series in line with the dorsal vertebrae. Thus, it appears
unlikely that it could have been a balancing organ for arboreal life, as
might be suggested by its relationship with _Megalancosaurus_ and
_Drepanosaurus_. Evidently, _Hypuronector_ had a beak anteriorly, as judged
from the pointed but toothless anterior mandible, the functional
significance of which is obscure."
Colbert, E.H. and Olsen, P.E. (2001). A new and unusual aquatic reptile
from the Lockatong Formation of New Jersey (Late Triassic, Newark
Supergroup). Am. Mus. Novit. 3334: 1?24.
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