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A partial skeleton of an enantiornithine bird from the Early Cretaceous of Northwestern China

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Lamanna M. C., You H.-L., Harris J. D., Chiappe L. M., Ji S.-A., Lu J.-C., Ji Q.

Acta Palaeontologica Polonica

2006

tom 51

nr 3

Although recent discoveries from Lower Cretaceous sediments in northeastern China have greatly improved our understanding of the initial stages of avian diversification in eastern Asia, the early evolution of Aves elsewhere on the continent remains poorly understood. In 2004, a collaborative field effort directed by personnel from the Chinese Academy of Geological Sciences and Carnegie Museum of Natural History recovered multiple partial to nearly complete avian skeletons from outcrops of the Lower Cretaceous Xiagou Formation exposed in the Changma Basin of northwestern Gansu Province, China. Here we describe a thrush−sized partial skeleton comprised of a fragmentary pelvic girdle and largely complete hind limbs. A phylogenetic analysis of 20 avian ingroup taxa and 169 anatomical characters places the specimen in Enantiornithes, and within that clade, in Euenantiornithes. When coupled with additional recent discoveries from the Changma Basin, the new skeleton improves our understanding of early avian evolution and diversification in central Asia.

Anatomy of the Early Cretaceous enantiornithine bird Rapaxavis pani

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O'Connor J. K., Chiappe L. M., Gao C., Zhao B.

Acta Palaeontologica Polonica

2011

tom 56

nr 3

The exquisitely preserved longipterygid enantiornithine Rapaxavis pani is redescribed here after more extensive preparation. A complete review of its morphology is presented based on information gathered before and after preparation. Among other features, Rapaxavis pani is characterized by having an elongate rostrum (close to 60% of the skull length), rostrally restricted dentition, and schizorhinal external nares. Yet, the most puzzling feature of this bird is the presence of a pair of pectoral bones (here termed paracoracoidal ossifications) that, with the exception of the enantiornithine Concornis lacustris, are unknown within Aves. Particularly notable is the presence of a distal tarsal cap, formed by the fusion of distal tarsal elements, a feature that is controversial in non−ornithuromorph birds. The holotype and only known specimen of Rapaxavis pani thus reveals important information for better understanding the anatomy and phylogenetic relationships of longipterygids, in particular, as well as basal birds as a whole.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Chiappe L. M.

1 Gao C.

1 Harris J. D.

1 Ji Q.

1 Ji S.-A.

1 Lamanna M. C.

1 Lu J.-C.

1 O'Connor J. K.

1 You H.-L.

1 Zhao B.

1 2011

1 2006

Wyniki wyszukiwania

A partial skeleton of an enantiornithine bird from the Early Cretaceous of Northwestern China

Anatomy of the Early Cretaceous enantiornithine bird Rapaxavis pani