[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Science feather strength debate
Augusto Haro <email@example.com> wrote:
> May the lenght of the forelimb coupled with the inferred phylogenetic
> allegiances of the material (with recent birds), still suggest so?
Length of forelimb:
Many coelurosaurs have elongated forelimbs, although those of
_Archaeopteryx_ are among the longest (outside Ornithothoraces).
However, there is no reason to automatically assume that forelimb
elongation in a feathered non-ornithithoracine theropod is
flight-related. Longer forelimbs also improve reach - such as for
prey capture (e.g., dromaeosaurs), or procuring branches (e.g.,
therizinosaurs), or possibly climbing (e.g., _Yixiansaurus_,
Having said that, the type and arrangement of feathers in
_Archaeopteryx_ does certainly indicate some form of aerial behavior.
But this returns me to my original point: it's the feathers that are
telling us this, not the skeleton. Osteologically, there is nothing
about _Archaeopteryx_ that points to it being a flier. We tend to
interpret the osteology of _Archaeopteryx_ through the prism of its
feathered plumage. IMHO, it should be the other way round.
Inferred phylogenetic allegiances:
This depends entirely upon the phylogenetic position of
_Archaeopteryx_ vis-a-vis modern birds (crown Aves). If
deinonychosaurs and/or oviraptorosaurs are found to be closer to crown
Aves than is _Archaeopteryx_, then the hypothesis that _Archaeopteryx_
was a powered flier is undermined even further.
Current phylogenies, in which _Archaeopteryx_ forms a clade with crown
Aves to the exclusion of deinonychosaurs and oviraptorosaurs, don't
actually point to _Archaeopteryx_ being a powered flier. This is
because wings composed of closed pennaceous feathers occur outside
this clade, having been found in some deinonychosaurs.