A new ornithuromorph (Aves: Ornithothoraces) bird from the Jehol Group indicative of higher-level diversity

Department of Earth Sciences, University of Southern California, 90089, Los Angeles, California, U.S.A; The Dinosaur Institute, Natural History Museum of Los Angeles County, 90007, Los Angeles, California; U.S.A; School of Earth and Space Sciences, Peking University, 100871, Beijing, People's Republic of China
Journal of Vertebrate Paleontology (Impact Factor: 2.08). 04/2010; 30:311-321. DOI: 10.1080/02724631003617498

ABSTRACT Basal Ornithuromorpha, until recently, was one of the most poorly documented segments of early avian evo-lution. The known species diversity of the ornithuromorph clade has increased rapidly with the addition of new discoveries from the Early Cretaceous deposits of northeastern China. Reported in this paper is the discovery of a new bird from the Lower Cretaceous Yixian Formation, Liaoning Province, China. The specimen represents a new species, Longicrusavis houi, but bears similarities to Hongshanornis longicresta from the same formation of Inner Mongolia. The two birds are compa-rable in size and share an unusual sigmoid mandible and elongate hindlimbs relative to their forelimbs. Together these taxa represent a clade (Hongshanornithidae, new taxon) of specialized 'shorebirds' whose elongate hindlimbs indicate ecological adaptations different from those of other Jehol ornithuromorphs. Phylogenetic relationships of Mesozoic birds are discussed based on the results of a comprehensive cladistic analysis. New morphological information on Ornithuromorpha is provided through the detailed description of the new taxon together with new information on Hongshanornis.

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