Bone fusion in primitive birds

Researchers describe patterns of bone fusion related to flight in a primitive bird from the Early Cretaceous. The skeletons of birds exhibit bone fusions in the hands, feet, and pelvis that make flight possible. However, due to a lack of transitional fossils and developmental studies in modern birds, the evolutionary history of bone fusion in birds remains unclear. Min Wang and colleagues report a primitive bird specimen from the Early Cretaceous -- around 120 million years ago -- that displays a high degree of skeletal fusion in manus and pelvis bones. The bird, known as Pterygornis, belonged to the Enantiornithes, which represents what was likely the most diverse group of birds during the Mesozoic Era. The specimen exhibits bone fusion in the alular-major metacarpals and the ilium, ischium, and pubis pelvis bones, features that are rare in the majority of known birds from the Early Cretaceous. Osteohistological analysis indicates that Pterygornis followed a growth strategy exhibited by most modern birds, reaching skeletal maturity in approximately 1 year. The authors posit that the bone fusion morphology observed in Pterygornis might be due to a refinement of flight capability or genetic modifications in primitive birds. According to the authors, the findings shift backward the evolutionary timing for carpometacarpus and pelvis fusion in birds by more than 40 million years.

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Article #17-07237: "Insight into the growth pattern and bone fusion of basal birds from an Early Cretaceous enantiornithine bird," by Min Wang, Zhiheng Li, and Zhonghe Zhou.

MEDIA CONTACT: Zhonghe Zhou, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, CHINA; tel: +86-01088369153; e-mail: <zhouzhonghe@ivpp.ac.cn>; Min Wang, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, CHINA; tel: +86-01088369153, +86-01088360062; e-mail: <wangmin@ivpp.ac.cn>

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