New Chinese Early Cretaceous bird taxa...

[Brad McFeeters <archosauromorph2@hotmail.com>]

Zhou Zong-He & Zhang Fu-Cheng, 2006.  Mesozoic birds of China: a synoptic 
review.  Vertebrata PalAsiatica 44 (1): 74-98.  
http://www.ivpp.ac.cn/pdf/magazine196.pdf

Abstract:  A synoptic review of the discoveries and studies of the Chinese 
Mesozoic birds is provided in this paper.  40Ar/39Ar dating of several 
bird-bearing deposits in the Jehol Group has established a geochronological 
framework for the study of the early avian radiation.  Chinese Mesozoic 
birds had lasted for at least 11 Ma during about 131 Ma and 120 Ma 
(Barremian to Aptian) of the middle and late Early Cretaceous.  In order to 
evaluate the change of the avian diversity in the Jehol Biota, six new 
orders and families are erected based on known genera and species, which 
brings the total number of orders of Chinese Mesozoic birds to 15 and 
highlights a remarkable radiation ever since the first appearance of birds 
in the Late Jurassic.  Chinese Early Cretaceous birds had experienced a 
significant differentiation in morphology, flight, diet and habitat.  
Further examination of the foot of *Jeholornis* suggests this bird might not 
have possessed a fully reversed hallux.  However, the attachment of 
metatarsal I to the medial side of metatarsal II does not preclude trunk 
climbing, a pre-adaptation for well developed perching life of early birds.  
Arboreality had proved to be a ket adaptation in the origin and early 
evolution of bird flight, and the adaptation to lakeshore environment had 
played an equally important role in the origin of ornithurine birds and 
their near-modern flight skill.  Many Chinese Early Cretaceous birds had 
preserved the direct evidence of their diet, showing that most primitive 
birds were probably mainly insectivorous and that specialized herbivorous or 
carnivorous (e.g., piscivorous) dietary adaptations had appeared only in 
later advanced forms.  The only known Early Cretaceous bird embryo fossil 
has shown that precocial birds had occurred prior to altricial birds in 
avian history, and the size o the embryo and other analysis indicate it 
probably had a short incubation period.  Leg feathers probably have a wide 
distribution in early birds, further suggesting that leg feathers played a 
key role in the beginning stage of the flight of birds.  Finally, the Early 
Cretaceous avian radiation can be better understood against the backdrop of 
their unique ecosystem.  The advantage of birds in the competition with 
other vertebrate groups such pterosaurs had probably not only resulted in 
the rapid differentiation and radiation of birds but also the worldwide 
speading of pterosaurs and other vertebrates from Easy Asia in the Early 
Cretaceous.

New "orders" and "families" named in this paper:

Jeholornithiformes
Jeholornithidae
Sapeornithiformes
Sapeornithidae
Boluochiformes
Boluochidae
Protopterygiformes
Protopterygidae
Longirostravisiformes
Longirostravisidae
Yixianornithiformes
Yixianornithidae

No phylogenetic definitions, and they all currently contain just a single 
species.  *Otogornis genghisi* seems to be listed as a longirostravisid in a 
table, perhaps by error, because only *Longirostravis hani* is listed as an 
included taxon in the diagnosis of Longirostravisiformes/idae.  
*Shenzhouraptor* and *Jixiangornis* are both said to be junior synonyms of 
*Jeholornis*.  A recent discovery of a jeholornithiform bird in the Yixian 
Formation is mentioned, but not yet described.