Microraptorian Jian changmaensis described from China's Changma Basin, with a wingspan of about one metre

Palaeontologists have described a new dinosaur species, Jian changmaensis, from the Changma Basin in Gansu Province, northwestern China. The work was published in Annals of Carnegie Museum, as reported by innovanews.ru. innovanews.ruinnovanews.ruinnovanews.ruOpen source ↗ It is a microraptorian, a member of the dromaeosaurs, close relatives of birds. The authors suggest it may be the predator that left clumps of crushed bird bones in these layers.

The puzzle of the bone clumps

The Changma layers have yielded hundreds of skeletons of ancient birds. Some of the thin bones are crushed and gathered into clumps resembling the pellets that owls produce today. For many years researchers did not know which predator made them, because there was no direct evidence.

Jingmai O'Connor, associate curator of fossil reptiles at the Field Museum in Chicago and senior author of the paper, calls Jian the team's best explanation. She notes that it is the only non-avian dinosaur found in these layers, and a predator noticeably larger than the other finds. The unusual structure of the humerus and forelimb bones was the basis for the proposal. This remains the authors' hypothesis, not a confirmed link.

Matt Lamanna, corresponding author and curator of vertebrate paleontology at the Carnegie Museum of Natural History, reported that the team collected more than a hundred bird fossils at Changma but only one specimen of a non-avian dinosaur. innovanews.ruinnovanews.ruinnovanews.ruOpen source ↗

Size and appearance of Jian changmaensis

Microraptorians were usually small, and the best-known species is about the size of a crow. Jian is one of the largest microraptorian specimens found. The preserved humerus fragment is about ten centimetres long, so the wingspan, in O'Connor's estimate, was probably a little over a metre, similar to a barn owl.

Only a forelimb of Jian is known. The researchers assume that, as in other microraptorians, long feathers grew on both the forelimbs and the hindlimbs, giving the animal the look of having four wings. Such dinosaurs were unlikely to flap and fly, but could probably glide, like a flying squirrel.

The name reflects the bird-like appearance and the place of discovery: jian is a winged creature from Chinese mythology, and the fossil was found in the Changma Basin. innovanews.ruinnovanews.ruinnovanews.ruOpen source ↗ According to Lamanna, the find adds to knowledge of the biological history of the area and the ecological context of the ancestors of modern birds.