Microraptor zhaoianus MY-kroh-RAP-tor

"Tiny thief"

Microraptor silhouette — silhouette · T. Michael Keesey (CC0) via PhyloPic

Length: 80 cm (2.6 ft) — About 80 cm long, 1 kg — crow-sized, four-winged.
Period: Early Cretaceous (125–120 Mya)
Place: Asia · China · Liaoning Province
Food: Carnivore — Small prey — fish, lizards, early birds, mammals (one specimen preserved with a mammal's foot in its stomach).
Clade: Dromaeosauridae Dinosauria Saurischia Theropoda Coelurosauria Sickle-clawed raptors: Velociraptor, Deinonychus, Utahraptor.

A tiny dinosaur with feathered surfaces on all four limbs that may have glided for lift.

Microraptor had four wings. Long flight feathers grew on both its arms and its legs, making it look like a kind of biplane glider. It probably couldn’t take off from the ground like a modern bird, but it could glide between trees. Hundreds of specimens have been found in Chinese lake deposits, sometimes with feathers and even gut contents preserved.

More about Microraptor

Discovery

Named by Xu Xing · 2003 · Liaoning, China

Numerous well-preserved fossils came from the early Cretaceous Jiufotang Formation in Liaoning. In 2003 Xu Xing described the first specimen preserving feathered surfaces on all four limbs as a four-winged dinosaur.

The name combines Greek "mīkros" (small) with Latin "raptor" (one who seizes), so it means roughly "small seizer."

Xu Xing. A paleontologist at Beijing's Institute of Vertebrate Paleontology and Paleoanthropology who revealed the Archaeoraptor forgery and went on to name Microraptor and describe it as a four-winged dinosaur.

Could Microraptor actually fly, or did it only glide?

Long pennaceous feathers formed aerodynamic surfaces on the arms, tail, and legs. Xu Xing in 2003 speculated it may have glided using all four limbs for lift, and later studies have suggested it was capable of powered flight as well.

How many species of Microraptor are there really?

Three species have been named (M. zhaoianus, M. gui, and M. hanqingi). Further study has suggested they all represent variation within a single species, properly called M. zhaoianus, and the separate genus Cryptovolans is usually treated as a synonym of Microraptor.

What we know

Real flight feathers on both arms AND legs — a true four-winged glider.
Studied melanosomes show its feathers were glossy black, like a starling.
Stomach contents in different specimens include fish, a bird, a lizard, and a mammal — a generalist hunter.
Hundreds of specimens recovered from the Yixian Formation in China.

What we guess

Whether Microraptor flew under power, only glided, or did both.
How the leg wings were held in flight — splayed sideways or trailing behind?
Whether four-winged flight was a step toward modern bird flight or a separate experiment.