Longisquama "feathers"

[David Peters <davidrpeters@earthlink.net>]

I would have to agree with Tim in that the dorsal appendages of
Longisquama are developed in a single file.

Such an exotic growth would seem to have to have had some sort of
smaller, less exotic and more common precedent. The only apparent
precedent that I can imagine is in the dorsal frill of Sphendon, Iguana,
Huehuecuetzpalli, Macrocnemus and Cosesaurus ? in that order.

What I don't understand is their detached nature. Are the frills of
Sphenodon and Iguana shed in bits and pieces?

DP
StL



Michael Mortimer wrote:


         It's good they're looking for more material though. Of course,
actually describing the holotype well would be a good thing too. Their
model
         is quite funny, with pararetrices.


To add to what Mickey said, there is actually no proof that these
appendages ('pararetrices') were paired, or even mobile. The model in
the photo was
perhaps influenced by Haubold and Buffetaut (1987), who reconstructed
_Longisquama_ as a gliding reptile like _Coelurosauravus_,
kuehneosaurids, or
the modern_Draco_. Haubold and Buffetaut suggested that _Longisquama_
used its appendages as a continuous gliding surface, which was folded
over the
back when not in use - sort of like a butterfly. There is no actual
evidence supporting this scenario, given that the holotype specimen
seems to only show
a single dorsal row of plume-like appendages. Of course, it could be
that the other side of the gliding 'wing' was not preserved; but this
would not be the
most parsimonious explanation.

Cheers


Tim