ScienceDaily (Mar. 25, 2010) — The study of Mesozoic birds and the dinosaur-bird transition is one of the most exciting and vigorous fields in vertebrate paleontology today. A newly described bird from the Jehol Biota of northeast China suggests that scientists have only tapped a small proportion of the birds and dinosaurs that were living at that time, and that the rocks still have many secrets to reveal.
Life reconstruction of Longicrusavis houi in what was probably its favored habitat, shallow lake waters. A reconstruction of the fossil specimen itself is reflected in the water. (Credit: Illustration by Stephanie Abramowicz, Dinosaur Institute, Natural History Museum of Los Angeles County.)
"The study of Mesozoic birds is currently one of the most exciting fields; new discoveries continue to drastically change how we view them," said Jingmai O'Connor, lead author of the study. The article appeared in the March issue of theJournal of Vertebrate Paleontology.
The new bird, named "Longicrusavis houi," belongs to a group of birds known as ornithuromorphs (Ornithuromorpha), which are rare in rocks of this age. Ornithuromorphs are more closely related to modern birds than are most of the other birds from the Jehol Biota.
"Longicrusavis adds to the magnificent diversity of ancient birds, many of them sporting teeth, wing claws, and long bony tails, that recently have been unearthed from northeastern China," said Luis Chiappe, a co-author of the study.
Along with a bird described five years ago, Longicrusavisprovides evidence for a new, specialized group of small birds that diversified during the Early Cretaceous between about 130 and 120 million years ago.
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Authors: Jingmai K. O'Connor ab; Ke-Qin Gao c;Luis M. Chiappe b
Affiliations:
a Department of Earth Sciences, University of Southern California, Los Angeles, California, U.S.A.
b The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, California, U.S.A.
c Peking University, School of Earth and Space Sciences, Beijing, People's Republic of China
DOI: 10.1080/02724631003617498
Published in: Journal of Vertebrate Paleontology, Volume 30, Issue 2 March 2010 , pages 311 - 321
b The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, California, U.S.A.
c Peking University, School of Earth and Space Sciences, Beijing, People's Republic of China
DOI: 10.1080/02724631003617498
Published in: Journal of Vertebrate Paleontology, Volume 30, Issue 2 March 2010 , pages 311 - 321
Basal Ornithuromorpha, until recently, was one of the most poorly documented segments of early avian evolution. 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 comparable 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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