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Re: Confuciusornis feather length and flight mode



Well, I'll be the first to say it. This paper does not seem to have
incorporated the data from Zheng et al. that Nudds et al. acknowledged in
their response last year (Science, Vol 33), page 320-d, 15 October 2010.
DOI: 10.1126/science.1193474). At that time Nudds et al. wrote that some
specimens (or possibly a distinct, volant, species) of Confuciusornis may
have been capable of flapping flight.

Though the primary feather length of Confuciusornithids is shown in this
new paper to group with volant ornithurines, the authors disregard the
possibility of flapping flight again. This conclusion seems to be based on
the conclusions of their earlier paper (and several other papers). This is
puzzling considering their admission that flapping flight was possible, so
long as Zheng et al's rachis measurements were used.

Perhaps they had a chance to examine Zheng et al.'s specimens and
ultimately disagreed about the rachis diameters?



> 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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Jason Brougham
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