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Re: New enantiornithine Chiappeavis magnapremaxillo with fan-shaped tail

Ben Creisler

In case some people couldn't read the message, here is the ref in
plain text. Many thanks for catching this one.

Jingmai K. O’Connor, Xiaoli Wang, Xiaoting Zheng, Han Hu, Xiaomei
Zhang & Zhonghe Zhou (2016)
An Enantiornithine with a Fan-Shaped Tail, and the Evolution of the
Rectricial Complex in Early Birds.
Current Biology (advance online publication)
DOI: http://dx.doi.org/10.1016/j.cub.2015.11.036


O’Connor et al. name a new pengornithid enantiornithine honoring Dr.
Luis Chiappe
The new specimen preserves strong evidence that an aerodynamic tail is present
These new data suggest that Shanweiniao had ornamental feathers
The unique pengornithid pygostyle may possess simple rectricial bulbs


The most basal avians Archaeopteryx and Jeholornis have elongate
reptilian tails. However, all other birds (Pygostylia) have an
abbreviated tail that ends in a fused element called the pygostyle. In
extant birds, this is typically associated with a fleshy structure
called the rectricial bulb that secures the tail feathers (rectrices).
The bulbi rectricium muscle controls the spread of the rectrices
during flight. This ability to manipulate tail shape greatly increases
flight function. The Jehol avifauna preserves the earliest known
pygostylians and a diversity of rectrices. However, no fossil directly
elucidates this important skeletal transition. Differences in plumage
and pygostyle morphology between clades of Early Cretaceous birds led
to the hypothesis that rectricial bulbs co-evolved with the
plough-shaped pygostyle of the Ornithuromorpha. A newly discovered
pengornithid, Chiappeavis magnapremaxillo gen. et sp. nov., preserves
strong evidence that enantiornithines possessed aerodynamic rectricial
fans. The consistent co-occurrence of short pygostyle morphology with
clear aerodynamic tail fans in the Ornithuromorpha, the
Sapeornithiformes, and now the Pengornithidae strongly supports
inferences that these features co-evolved with the rectricial bulbs as
a “rectricial complex.” Most parsimoniously, rectricial bulbs are
plesiomorphic to Pygostylia and were lost in confuciusornithiforms and
some enantiornithines, although morphological differences suggest
three independent origins.

On Sun, Jan 3, 2016 at 7:20 AM, Alberta Claw <albertonykus@gmail.com> wrote:
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