The Four-Winged Dinosaur
Oldest Bird Was Actually a Dinosaur

The Four-Winged Dinosaur
Oldest Bird Was Actually a Dinosaur

Long ago in the age of dinosaurs, a volcano in eastern China erupted and buried a host of strange creatures in ash, creating exquisite fossils that preserved a big surprise––many dinosaurs were covered in feathers.

In The Four-Winged Dinosaur, NOVA investigates the most bizarre of these feathered dinosaurs, which has rekindled a fierce, decades-long debate over the origin of bird flight.

Microraptor is a genus of small, four-winged feathered dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from within Liaoning, China. They date back from long ago, around 120 million years.

Microraptor provides very important evidence about the evolutionary relationship between the birds and the dinosaurs. Microraptor had long pennaceous feathers that formed aerodynamic surfaces on the arms and tail but also, surprisingly, on their legs as well.

This led paleontologist Xu Xing in 2003 to describe it as a "four-winged dinosaur" and to speculate that it may have glided using all four limbs for lift. Two species have been named, M. zhaoianus and M. gui, though further study has suggested that all of the specimens belong to a single species.

Microraptor was among the most abundant non-avialan dinosaurs in its ecosystem, and is represented by more fossils than any other dromaeosaurid, with possibly over 300 fossil specimens represented across various museum collections.

The Dinosaur Feather Mystery

With adult specimens ranging 77–90 centimeters long (2.53–3.0 feet) and with a weight estimated to be up to 1 kilogram (2.2 lbs), Microraptor was among the smallest known dinosaurs that were among the Earth.

Aside from its extremely small size, Microraptor was among the first non-avian dinosaurs discovered with the impressions of feathers and wings.

Three specimens of M. zhaoianus have been described in detail, in addition to two specimens of M. gui and three specimens of M. sp. described by Xu and colleagues in 2003, from which most feather impressions are known.

Unusual even among early birds and feathered dinosaurs, Microraptor is one of the few known bird precursors to sport long flight feathers on its feet as well as its forearms and hands.

Their bodies had a thick covering of feathers, with a diamond-shaped fan on the end of the tail which may have been used possibly for added stability during flight. Their teeth were a combination of unserrated and partially serrated. They also had unusually long upper arm bones.