Ambopteryx longibrachium: Tiny Jurassic Dinosaur Had Membranous Wings
A previously unknown species of bird-like dinosaur with pterosaur-like wings has been discovered by a team of paleontologists working with the Institute of Vertebrate Paleontology and Paleoanthropology and the Center for Excellence in Life and Paleoenvironment at the Chinese Academy of Science. The discovery, reported in the May 9 issue of the journal Nature, sheds some new light on the origins of avian flight.
Named Ambopteryx longibrachium, the new dinosaur lived approximately 163 million years ago (Jurassic period) in what is now China.
The prehistoric creature had a body length of about 12.6 inches (32 cm) and an estimated body mass of 300 g.
It belongs to Scansoriopterygidae, an extinct family of climbing and gliding non-avian theropod dinosaurs.
“Scansoriopterygids differ from other theropods in their body proportions, particularly in the proportions of the forelimb, which supports a bizarre wing structure first recognized in Yi qi, a close relative of Ambopteryx longibrachium,” said team leader Dr. Min Wang and colleagues.
“Unlike other flying dinosaurs, namely birds, these two species have membranous wings supported by a rod-like wrist bone that is not found in any other dinosaur, but is present in pterosaurs and flying squirrels.”
A nearly complete skeleton of Ambopteryx longibrachium was unearthed near Wubaiding Village in China’s Liaoning Province.
“Due to incomplete preservation in the only known specimen of Yi qi, the veracity of the unique wing structures and their exact function remained hotly debated,” the paleontologists said.
“As the most completely preserved specimen to date, Ambopteryx longibrachium preserves membranous wings and the rod-like wrist, supporting their widespread existence in Scansoriopterygidae.”
“These wing structures represent a short-lived and unsuccessful attempt to fly,” they added.
“In contrast, feathered wings, first documented in Late Jurassic non-avian dinosaurs, were further refined through the evolution of numerous skeletal and soft tissue modifications, giving rise to at least two additional independent origins of dinosaur flight and ultimately leading to the current success of modern birds.”
Min Wang et al. 2019. A new Jurassic scansoriopterygid and the loss of membranous wings in theropod dinosaurs. Nature 569: 256-259; doi: 10.1038/s41586-019-1137-z