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Re: Yi qi, bizarre new bat-winged theropod from Jurassic of China



Wow, what an oddball (and evolutionarily speaking, a curveball too).
In the Supplementary Information, the authors compare _Yi_ directly to
the living kakapo: "Among living birds, the parrot _Strigops
habroptilus_ (the kakapo) is a plausible locomotor analogue for _Yi_.
_Strigops habroptilus_ "is capable of significant descending glides,
during which it may flap its wings occasionally, and (rarely) brief,
weak, aerial ascents"".  Xu et al. cite Livezey (1992) for the quote
on the kakapo.

As Livezey (1992) additionally makes clear, the kakapo is- a
terrestrial bird that forages mostly on the ground, but is capable of
climbing trees to obtain food; it uses aerial locomotion to return to
earth.  If _Yi_ and _Epidendrosaurus_ did the same, then
"scansoriopterygid" is a highly appropriate name.  Inferences
regarding whether or not _Yi_ was truly arboreal (as opposed to
scansorial) will depend on the morphology of the feet - as yet
undiscovered.

In the accompanying commentary piece, Padian is tepid on _Yi_ being
capable of powered flight.  (The figure in Padian's article has a
minor typo - "_Epidexipteryx ningchengensis_" ought to be
_Epidexipteryx hui_.)

It's also worth noting that another small maniraptoran _Zhongornis_,
based on a juvenile specimen, has been interpreted as a
scansoriopterygid by O'Connor and Sullivan (2014).  In the original
description (Gao et al., 2008), traces of vaned feathers were
discerned associated with the right hand.


On Thu, Apr 30, 2015 at 3:27 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
>
> A new paper:
>
> Xing Xu,  Xiaoting Zheng, Corwin Sullivan, Xiaoli Wang, Lida Xing, Yan
> Wang, Xiaomei Zhang, Jingmai K. O’Connor,  Fucheng Zhang & Yanhong Pan
> (2015)
> A bizarre Jurassic maniraptoran theropod with preserved evidence of
> membranous wings.
> Nature (advance online publication)
> doi:10.1038/nature14423
> http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14423.html
>
>
> The wings of birds and their closest theropod relatives share a
> uniform fundamental architecture, with pinnate flight feathers as the
> key component. Here we report a new scansoriopterygid theropod, Yi qi
> gen. et sp. nov., based on a new specimen from the Middle–Upper
> Jurassic period Tiaojishan Formation of Hebei Province, China. Yi is
> nested phylogenetically among winged theropods but has large stiff
> filamentous feathers of an unusual type on both the forelimb and
> hindlimb. However, the filamentous feathers of Yi resemble pinnate
> feathers in bearing morphologically diverse melanosomes. Most
> surprisingly, Yi has a long rod-like bone extending from each wrist,
> and patches of membranous tissue preserved between the rod-like bones
> and the manual digits. Analogous features are unknown in any dinosaur
> but occur in various flying and gliding tetrapods, suggesting the
> intriguing possibility that Yi had membranous aerodynamic surfaces
> totally different from the archetypal feathered wings of birds and
> their closest relatives. Documentation of the unique forelimbs of Yi
> greatly increases the morphological disparity known to exist among
> dinosaurs, and highlights the extraordinary breadth and richness of
> the evolutionary experimentation that took place close to the origin
> of birds.
>
> ***
>
> Commentary:
>
> Kevin Padian (2015)
> Palaeontology: Dinosaur up in the air
> Nature (advance online publication)
> doi:10.1038/nature14392
> http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14392.html
>
>
> ====
>
>
> News:
>
> http://www.smithsonianmag.com/science-nature/fluffy-little-dinosaur-had-bat-wings-180955122/
>
> http://www.livescience.com/50663-bat-winged-dinosaur.html
>
> http://www.livescience.com/50662-bizarre-bat-dinosaur-photos.html
>
> http://news.discovery.com/animals/dinosaurs/bat-like-pigeon-sized-dino-soared-over-china-150429.htm
>
> http://www.theguardian.com/science/lost-worlds/2015/apr/29/bird-yi-qi-the-dinosaur-evolution-flight-feather-nature