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Re: How to use hindwings

Roberto Takata (rmtakata@gmail.com) wrote:

<Does /Microraptor/ legs have a keel?>

  My gut reaction is to say "no." The only described complete sternum for *M.
gui* at least is overlain along the midline by bone, obscuring whether it was
even fused at the midline, although it was described by Xu et al. as fused. In
*M. zhaoianus*, Hwang et al. describe separated sternal plates, so the coase of
fusion is moot and a keel ambiguous.

  However, while I would state that fusion should likely precede the presence
of a keel, specimens of oviraptorids have unfused sternae with a keel-like
structure to the midline, though this may pertain to overlap of the plates
rather than a thickening of the midline; one specimen of "Ingenia" has a fused
sternum, but this is said to be aberrant (Norell and Makovicky, 1997). The same
is true for *Velociraptor*, and more than one specimen shows a generally thin
plate without midline fusion or thickening (GIN 100/25 ["Fighting Dinosaurs"
specimen] and GIN 100/985).


Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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