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RE: Gliding squamate from the Yixian Fm

David Marjanovic wrote:

I am told (http://www.wissenschaft.de/wissenschaft/news/276176.html; in German) that PNAS has just prepublished *Xianglong zhaoi*, which looks like *Draco* or for that matter *Icarosaurus* but is not closely related to either, and is very well preserved, with strengthening fibers in the gliding membrane spanned between 8 lengthened ribs.

The patagium is reinforced by "tough parallel collagen fibers" otherwise only known in pterosaurs
and _Sharovipteryx_. As you say, _Xianglong_ is a squamate (iguanian), so this character is convergent.

The wings have "aerodynamic values" that resemble those of active fliers.

"The wing shape parameters, wing loading, aspect ratio, and the outer area proportions (one-fifth of the wing) are the three important indicators of aerial performance... _Xianglong_ is estimated to have a wing loading of 0.24 g/cm^2 (=23.5 N/m^2), an aspect ratio of 6.5, and an outer area proportion of 8% ... These ratios are close to those in fast-flying birds with great maneuverability, such as passeriforms."



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