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New enantiornithine bird



Zhang, Ericson and Zhou, 2004. Description of a new enantiornithine bird
from the Early Cretaceous
of Hebei, northern China. Canadian Journal of Earth Sciences. 41(9),
1097-1107.

Abstract: This paper describes a new enantiornithine fossil bird,
____________, nov. sp. from the Early Cretaceous of China. We refer ________
to the crown clade Euenantiornithes based on several characteristics
observed in the thoracic girdle and wing. _______ also exhibits
characteristics that separate it from other enantiornithine birds, such as
the short alular phalanx, the vestigial manual claws, and the well-developed
and long foot claws. These features suggest an adaptation towards an
improved flight capability, while the ability of _______ to climb is reduced
compared with many other enantiornithine birds.

It took some digging to find this pdf, as the URL's are hidden until printed
distribution due to the new taxa described (hence my replacing the name with
underscores above).  It's represented by a complete skeleton (NIGP 130722)
from the Jianshangou Beds of the Yixian Formation (Late Barremian-Early
Aptian) in Hebei.  The paper contains excellent closeup photographs and line
drawings, similar to the recent Sapeornis paper by two of the same authors.
Looks like a standard Early Cretaceous enant to me.  The short, thin first
manual phalanx I-1 is supposedly diagnostic, but those of Sinornis and
Concornis are shorter, while those of Eocathayornis and the Catalan nestling
are comparable.  Those of Eocathayornis, Concornis and Sinornis are also
comparable in width.  The manual unguals are smaller than in those genera,
but this varies widely in living species of bird.  The sternum looks a bit
more primitive than Sinornis and Concornis (shorter, less expanded
posterolateral processes, smaller posteromedial processes), but the specimen
is subadult, so this may be expected.  The coracoid is supposed to be
diagnostically elongate for an Early Cretaceous enantiornithine, but looks
comparable to Concornis' to me.  I'm not saying the new genus is invalid (I
haven't even read most of the paper yet), but it seems pretty similar to
other Early Cretaceous enantiornithines.
Interestingly, the authors mention Jibeinia, which has been basically
ignored by everyone since its publication.  Unfortunately, they report the
holotype is lost (Hou pers. comm., 2001) and the remaining casts are low
quality.  Bet Hou wishes he would have illustrated and described it better
now. ;)

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html