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Longisquama's "feather-like" appendages in new study



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Michael Buchwitz and Sebastian Voigt (2012)
The dorsal appendages of the Triassic reptile Longisquama insignis:
reconsideration of a controversial integument type.
Paläontologische Zeitschrift (advance online publication)
DOI: 10.1007/s12542-012-0135-3
http://www.springerlink.com/content/c25022htl3663053/


Elongated skin projections of the reptile Longisquama insignis from
the Triassic of Kyrgyzstan are preserved as imprints on the only
skeletal specimen and on seven additional pairs of fossil slabs and
counter-slabs from the same locality and horizon. The integumentary
structures became a matter of debate when they were assessed as
“non-avian feathers” homologous to avian feathers. Conflicting
interpretations of their morphology and relationship to other
appendage types arose from the ambiguity of the fossil skin
impressions. On the basis of comparative description of the individual
morphology of all yet known Longisquama specimens we address aspects
of taphonomy, development, and function and define to what extent
Longisquama’s appendages share characteristics of avian vaned
feathers. We explain the existing feather similarity by their
development from a filamentous primordium and a complex sequence of
individual processes, some of which are reminiscent of processes
observed in feather development. Such an interpretation is in
agreement with a set of homologous mechanisms of appendage
morphogenesis in an archosauromorph clade including Longisquama and
feather-bearing archosaurs but does not necessarily require that the
appendages of Longisquama themselves are feathers or high-level
feather homologues.