Schizooura, new ornithurine bird from Cretaceous of China (free pdf!)

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bscreisler@gmail.com

A paper in the new issue of Vertebrata PalAsiatica not yet mentioned
on the DML:

ZHOU Shuang, ZHOU Zhong-He & Jingmai K. O’CONNOR (2012)
A NEW BASAL BEAKED ORNITHURINE BIRD FROM THE LOWER CRETACEOUS OF
WESTERN LIAONING, CHINA.
Vertebrata PalAsiatica 50(1): 9-24
free pdf link:
http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/201202/P020120209570168040733.pdf


We report a new species of basal ornithurine bird, Schizooura lii gen.
et sp. nov., based on a well-preserved specimen from the Lower
Cretaceous Jiufotang Formation in Jianchang, western Liaoning, China.
Phylogenetic analysis indicates that it is more derived than
Jianchangornis and Archaeopteryx, but more basal than all other known
Jehol ornithurines. The new specimen preserves a unique suite of
characters that differentiate it from other known taxa, including
several features previously unreported in Early Cretaceous
ornithurines, including a V-shaped furcula with a short hypocleidium,
a rostrocaudally elongate unperforated sternum with deep caudal
notches absent, and a deltopectoral crest that extends for half the
length of the humerus. The specimen preserves a nearly perfectly
articulated ksull that indicates the species was beaked and preserves
details of the skull anatomy such as the premaxilla-frontal
articulation. The most notable feature of this specimen is the
preservation of a feathered tail morphology previously unknown among
Mesozoic birds. It is the second tail morphology known among early
ornithurines, which have until now only preserved fan-shaped tails.
The new specimen preserves a forked tail compose of elongate rectrices
medially separated by a deep notch. This tail feather morphology in
modern birds decreases aerodynamic efficiency relative to the
fan-shaped tail, but increases chance of sexual reproduction. This
discovery suggests that this tradeoff convergently evolved in basal
members of Ornithurae, and is consistent with the wooded environment
ment inferred for the Jehol.