Jian, named after a flying creature in Chinese mythology, is known from five shoulder and arm bones that are sufficiently different from Microraptor, a close relative that lived in China at roughly the same time, to show they were distinct species.
While the remains of Jian are too incomplete to show its broader anatomy, the researchers believe it resembled Microraptor, which had feather-covered arms and legs that gave the appearance of four wings.
All meat-eating dinosaurs belong to a group called theropods. Not all were enormous like Tyrannosaurus or Spinosaurus. There were many smaller ones that may have filled the same type of ecological niche as a weasel or wolverine today.
Birds evolved from small feathered dinosaurs during the Jurassic Period. The earliest-known bird, Archaeopteryx, dates to about 150 million years ago.
There would have been plenty of birds around to keep Jian well fed, including the pigeon-sized semi-aquatic Gansus, which likely had webbed feet and, like Archaeopteryx, possessed a mouthful of teeth. Some of the other birds known from this ecosystem are Feitianius, Changmaornis, Avimaia, Novavis and Meemannavis.
“Jian was probably an ambush predator, stalking and pouncing on distracted birds that were working on finding their own meals,” said paleontologist Jingmai O’Connor of the Field Museum in Chicago, also one of the study leaders.
“We know Microraptor was an opportunistic predator that fed on birds as well as lizards, mammals and even fish. Jian was likely the same, eating whatever it could catch. Dense bird populations may also have been seasonal, forcing Jian to have a diverse diet,” O’Connor said.
Velociraptor was about the size of a large turkey – much smaller than portrayed in films like “Jurassic Park.” It lived in Asia about 45 million years after Jian. Velociraptor, Jian and Microraptor are part of a larger group called dromaeosaurs, informally called raptors, with bodies adapted for speed and tenacity.
Perhaps the largest of the raptors was Utahraptor, which lived in North America about 15 million years before Jian appeared in China, and reached up to about 7m long. Jian would have been a bit more than 1m long, including its tail.
Referring to a lineage within the raptors that includes Jian and Microraptor, Lamanna said: “They’re extraordinarily closely related to the earliest birds such as Archaeopteryx – really, just about as close as you can be to being a bird without actually being a bird yourself.”