image: This is an Anchiornis specimen from Jianchang, western Liaoning. The sampling location is marked by a red box. view more
Credit: Yanhong Pan
Researchers report that modern bird feathers and feathers of the bird-like dinosaur Anchiornis have different protein compositions. Analyzing fossilized dinosaur feathers is key to uncovering how feathers evolved into appendages required for avian flight. Flight feathers are typically constructed of β-keratin proteins with a peptide deletion that provides biomechanical hardness and flexibility. Yanhong Pan, Mary H. Schweitzer, Zhonghe Zhou, and colleagues used electron microscopy and chemical analyses to compare flight feathers of a chicken to preserved forelimb feathers of the bird-like dinosaur Anchiornis. Whereas Anchiornis feathers lack the biomechanical properties needed for flight, they exhibit some of the necessary molecular structures. Anchiornis feathers are comprised of both α-keratins and β-keratins, which are also found in reptilian tissue and embryonic bird feathers. Although α-keratins, predominantly found in mammals, dominate the dinosaur feathers, β-keratins are essential proteins in the mature flight feathers of modern birds. Compared with modern bird feathers and fossilized feathers of four other dinosaurs from latter geological ages, Anchiornis feathers also contain lower concentrations of sulfur. The findings suggest that although Anchiornis feathers are not suitable for flight, the presence of β-keratins in the feathers' molecular structure may signify an intermediate stage in the evolution of avian flight feathers, according to the authors.
Article #18-15703: "The molecular evolution of feathers with direct evidence from fossils," by Yanhong Pan et al.
MEDIA CONTACTS: Yanhong Pan, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, CHINA; tel: 86-2583282241; email: yhpan@nigpas.ac.cn; Mary H. Schweitzer, North Carolina State University, Raleigh NC; tel: 919-515-7838, 919-515-7777; email: schweitzer@ncsu.edu; Zhonghe Zhou, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, CHINA; tel: +86-1088369153; email: zhouzhonghe@pa.ivpp.ac.cn
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