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Scansoriopteryx, a non-dinosaurian bird (?)



Ben Creisler
bcreisler@gmail.com

A new online paper:

Stephen A. Czerkas & Alan Feduccia (2014)
Jurassic archosaur is a non-dinosaurian bird.
Journal of Ornithology (advance online publication)
DOI: 10.1007/s10336-014-1098-9
http://link.springer.com/article/10.1007/s10336-014-1098-9

Re-examination utilizing Keyence 3D digital microscopy and low angled
illumination of the fossil Scansoriopteryx, a problematic sparrow-size
pre-Archaeopteryx specimen from the Jurassic Daohugou Biotas, provides
new evidence which challenges the widely accepted hypothesis that
birds are derived from dinosaurs in which avian flight originated from
cursorial forms. Contrary to previous interpretations in which
Scansoriopteryx was considered to be a coelurosaurian theropod
dinosaur, the absence of fundamental dinosaurian characteristics
demonstrates that it was not derived from a dinosaurian ancestry and
should not be considered as a theropod dinosaur. Furthermore, the
combination in which highly plesiomorphic non-dinosaurian traits are
retained along with highly derived features, yet only the beginnings
of salient birdlike characteristics, indicates that the basal origins
of Aves stemmed from outside the Dinosauria and further back to basal
archosaurs. Impressions of primitive elongate feathers on the
forelimbs and hindlimbs suggest that Scansoriopteryx represents a
basal form of “tetrapteryx” in which incipient aerodynamics involving
parachuting or gliding was possible. Along with unique adaptations for
an arboreal lifestyle, Scansoriopteryx fulfills predictions from the
early twentieth century that the ancestors of birds did not evolve
from dinosaurs, and instead were derived from earlier arboreal
archosaurs which originated flight according to the traditional
trees-down scenario.