[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Zhou Zhonghe and Fucheng Zhang, 2003. Anatomy of the primitive bird
Sapeornis chaoyangensis from the Early Cretaceous of Liaoning, China. Can.
J. Earth Sci. 40(5): 731-747
Abstract: Two new, nearly completely articulated skeletons of Sapeornis
chaoyangensis provide much new information about the anatomy of this basal
avian, particularly in the skull, pectoral girdle, forelimb, and hind limb.
This new material shows that the hand of Sapeornis, with a phalangeal
formula of "2?3?2," was more derived than previously reconstructed. The
skeleton of Sapeornis has several unique features, such as a distinctively
elongated fenestra on the proximal end of the humerus, a robust furcula with
a distinctive hypocleidum, and an elongated forelimb. Sapeornis exhibits a
combination of derived and primitive features, including a short, robust
non-strut-like coracoid and a fibula reaching the distal end of the tarsal
joint (as in Archaeopteryx), a pygostyle, reduced manual digits, and a
well-fused carpometacarpus (as in more advanced birds). These features
further indicate the mosaic pattern in the early evolution of birds and
confirm the basal position of Sapeornis near Archaeopteryx and Jeholornic in
the phylogeny of early birds. The preservation of gastroliths in one of the
new specimens also represents the first Chinese Mesozoic bird with such
evidence, indicating a herbivorous feeding habit and providing further
evidence for our understanding of the diet diversification in early avian
Tired of spam? Get advanced junk mail protection with MSN 8.