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Confuciusornis feather length and flight mode



From: Ben Creisler
bh480@scn.org

A new paper about Confuciusornis:

WANG X., R. L. NUDDS, G. J. DYKE (2011)
The primary feather lengths of early birds with respect to avian wing shape
evolution.
Journal of Evolutionary Biology advance online publication
Article first published online: 18 MAR 2011
DOI: 10.1111/j.1420-9101.2011.02253.x


Abstract
We examine the relationships between primary feather length (fprim) and
total arm length (ta) (sum of humerus, ulna and manus lengths) in Mesozoic
fossil birds to address one aspect of avian wing shape evolution. Analyses
show that there are significant differences in the composition of the wing
between the known lineages of basal birds and that mean fprim (relative to
ta length) is significantly shorter in Archaeopteryx and enantiornithines
than it is in Confuciusornithidae and in living birds. Based on outgroup
comparisons with nonavian theropods that preserve forelimb primary
feathers, we show that the possession of a relatively shorter fprim
(relative to ta length) must be the primitive condition for Aves. There is
also a clear phylogenetic trend in relative primary feather length
throughout bird evolution: our analyses demonstrate that the fprim/ta ratio
increases among successive lineages of Mesozoic birds towards the crown of
the tree (?modern birds?; Neornithes). Variance in this ratio also
coincides with the enormous evolutionary radiation at the base of
Neornithes. Because the fprim/ta ratio is linked to flight mode and
performance in living birds, further comparisons of wing proportions among
Mesozoic avians will prove informative and certainly imply that the aerial
locomotion of the Early Cretaceous Confuciusornis was very different to
other extinct and living birds.


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