Four "Wings"?

[Recusant]

Well, not quite wings, but on their way. A dinosaur whose rear legs had something like flight feathers. I suppose it could evolve into a real flyer with a sort of tail assembly that came off the rear haunches. Or maybe not. 

"Newfound velociraptor cousin probably glided on four 'wings' and hunted early birds" | Phys.org

The new microraptor dinosaur Jian changmaensis (left) attacks the early bird Gansus yumenensis (right) in what is now the Changma Basin of northwestern China approximately 120 million years ago. Credits: illustration by Lewis LaRosa, colorized by Jão Canola

A fossil bed in northwestern China is littered with the remains of hundreds of prehistoric birds—including some whose broken bones were crushed into pellets, similar to those coughed up by modern owls. For years, scientists guessed that a larger predatory animal must have hunted these ancient birds, but they never found direct fossil evidence of this predator.

Now, in a new paper published in the Annals of Carnegie Museum, researchers announce the discovery of a new species of dinosaur from this fossil bed—a cousin of the velociraptor with long feathers on its front and back limbs. Based on the dinosaur's distinctive arm and shoulder bones, scientists hypothesize that this animal is the missing predator.

"Scientists have found these weird, broken-up clusters of bird bones at this site, and we didn't know what made them. This new microraptor dinosaur, Jian changmaensis, is our best guess," says Jingmai O'Connor, the associate curator of fossil reptiles at the Field Museum in Chicago and senior author of the paper describing the new species. "It's the only dinosaur found at this site that wasn't a bird, it was a carnivore, and it was much bigger than everything else that we've found there."

Modern birds are the only group of dinosaurs that survived the aftereffects of a meteorite hitting Earth 66 million years ago. But birds and their fellow dinosaurs lived together for tens of millions of years in the Jurassic and Cretaceous periods.

One group of dinosaurs, the dromaeosaurs, were close cousins of the bird-dinosaurs. Dromaeosaurs, like birds, were covered in feathers and tended to be relatively small and speedy. The velociraptors made famous in Jurassic Park are probably the most famous dromaeosaurs (but they would have been smaller and more feathery than they're depicted in the movies).

The new species, Jian changmaensis, belongs to a clade within the dromaeosaur family called microraptors. Microraptors tend to be small; the most well-known species is about the size of a crow. "Jian is one of the biggest microraptor specimens that has ever been found," says O'Connor. "The piece of its upper arm bone that we have is about 4 inches long, so the entire dinosaur probably had something like a four-foot wingspan, around the size of a barn owl."

[Continues . . .]

The paper is available as a PDF:

"First Non-Avian Theropod (Dromaeosauridae, Microraptorinae) From the Bird-Bearing Lower Cretaceous Xiagou Formation of the Changma Basin, Gansu Province, Northwestern China" | Annals of Carnegie Museum

Abstract:

Lacustrine sediments of the Lower Cretaceous (lower Aptian) Xiagou Formation exposed near the village of Changma in the Changma Basin of northwestern Gansu Province, China have yielded more than 100 avian partial skeletons, many of which also preserve remnants of soft tissues such as feathers and skin. Collectively, these fossils characterize a rich avifauna dominated by the crownward ornithuromorph Gansus yumenensis Hou and Liu, 1984. Despite this wealth of Early Cretaceous bird material, no skeletal remains of other dinosaurs have been described from Changma to date.

Here we report the first non-avian dinosaur body fossil from the Xiagou Formation of the Changma Basin. Consisting of an articulated left pectoral girdle and forelimb lacking the carpus and manus, the specimen pertains to a new dromaeosaurid theropod taxon, Jian changmaensis, gen. et sp. nov.

Phylogenetic analysis recovers Jian within Microraptorinae, expanding the definitive fossil record of this clade to include northwestern China. The new Changma microraptorine constitutes an additional similarity between the theropod faunas of the Xiagou Formation of the Changma Basin and penecontemporaneous strata of the Jehol Group of northeastern China.

In particular, the Changma theropod assemblage closely resembles that of the Sihedang locality of the Jehol Group in that both include representatives of Microraptorinae and are overwhelmingly dominated by single ornithuromorph taxa that phylogenetic analyses have repeatedly resolved as close relatives. This raises the possibility that the two sites were deposited under comparable paleoenvironmental settings that are otherwise poorly represented at known Jehol localities.