Ambopteryx longibrachium – A New Bat-winged Dinosaur

Scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), have identified a new species of flying dinosaur from Jurassic-aged strata in north-eastern China.  This dinosaur has been identified as a member of the Scansoriopterygidae dinosaur family and it had bat-like, membranous wings just like the related Yi qi, that was named and described back in 2015.  The little dinosaur, not much bigger than a starling, had a flap of skin from its arms to its torso, in essence a wing.  It has been named Ambopteryx longibrachium and this discovery supports the idea that within the forests of northern China during the Middle to the Late Jurassic, dinosaurs were experimenting with several different methods of gliding and powered flight.

A Life Reconstruction of the Newly Described Scansoriopterygid Dinosaur Ambopteryx longibrachium

Ambopteryx longibrachium life reconstruction.

A life illustration of Ambopteryx longibrachium.

Picture Credit: IVPP (Chinese Academy of Sciences)

Bizarre and Buck-toothed Little Flying Dinosaur

The fossil specimen was found by a local farmer who supplements his income like many folk in Liaoning Province by searching for fossils in the fine-grained sediments.  It is beautifully preserved and dates to around 163 million years ago, commenting on the discovery, one of the co-authors of the scientific paper, published this week in the journal “Nature”, Jingmai O’Connor of the IVPP stated:

“It would have been this tiny, bizarre-looking, buck-toothed thing like nothing alive today.”

The Beautifully Preserved Fossil Specimen (Ambopteryx longibrachium)

Ambopteryx fossil specimen.

Ambopteryx longibrachium fossil.

Picture Credit: Min Wang IVPP (Chinese Academy of Sciences)

A Secondary Form of Flight That Does Not Involve Feathers

Close to the origins of flight, dinosaurs closely related to birds were experimenting with a range of different wing structures.  One of the most bizarre of these is the scansoriopterygid named Yi qi, (pronounced: Ee-chee), which was described and named in 2015.  This little dinosaur had membranous wings, supported by a curved, rod-like bone (styliform), attached to the wrist.  Soft tissue proximal to the arm bones was interpreted as bat-like wings, although this interpretation was not widely accepted by the scientific community.  However, the discovery of another type of scansoriopterygid dinosaur with the same type of wings demonstrates that members of the Scansoriopterygidae were indeed taking to the air.

The new dinosaur, Ambopteryx longibrachium (meaning “both-wing” and “long arm,” a reference to this second method of dinosaur flight, one that does not involve feathered wings), provides confirmatory evidence of the evolution of dinosaurs with bat-like, membranous wings.

Palaeontologist Steve Brusatte, (University of Edinburgh), when asked to reflect on the significance of this newly published scientific paper commented:

“This fossil seals the deal, there really were bat-winged dinosaurs.”

Ambopteryx longibrachium – Takes to the Air

A gliding Ambopteryx longibrachium (dorsal view).

Ambopteryx longibrachium (dorsal view).  The speculated flying pose of this new Chinese dinosaur.

Picture Credit: Min Wang IVPP (Chinese Academy of Sciences)

An Evolutionary Dead End

The researchers conclude that marked changes in wing design evolved near the split between the Scansoriopterygidae and the avian lineage, the two clades took very different routes to becoming volant.  Furthermore, the scientists determine that the membranous wings supported by elongate forelimbs present in scansoriopterygids such as Yi and Ambopteryx was a short-lived evolutionary experiment and that the feathered, winged dinosaurs ultimately proved to be the more successful leading to the eventual evolution of the Aves.  The likes of Yi qi and Ambopteryx longibrachium were evolutionary dead ends.  Whether Ambopteryx was capable of sustained powered flight, or whether it moved from tree to tree entirely by passive gliding remains unknown.

Coming in to Land – Ambopteryx longibrachium

At home amongst the trees Ambopteryx longibrachium.

Coming into land, a gliding Ambopteryx moving effortlessly from tree to tree.

Video Image Credit: Min Wang IVPP (Chinese Academy of Sciences)

Stomach Contents Preserved

The stomach contents of the little dinosaur have been preserved.  The Chinese scientists recovered pieces of bone and small stones (gastroliths), which modern birds use to grind plant material, indicating Ambopteryx may have been omnivorous.  It may have lacked pinnate feathers, but the body was covered by a downy fuzz to help this small dinosaur keep warm.  Jingmai O’Connor speculates that male Ambopteryx may have sported long, ornamental tail feathers, as seen in other scansoriopterygids such as Epidexipteryx (E. hui).

The scientific paper examines the anatomical traits that enabled a mode of flight.  The wings of Ambopteryx were formed by elongated arm bones (humerus and ulna).  Aves (birds), have elongated finger bones (metacarpals), in effect, different solutions found in nature to achieve the same aim – volant activity.

Professor O’Connor added:

“The main lift-generating surface of bird’s wings is formed by the feathers.  In bats, pterosaurs and now scansoriopterygids, you have instead flaps of skin that are stretched out in between skeletal elements.”

Yi qi was Not Alone

It seems likely therefore, that with the discovery of a second bat-winged scansoriopterygid, there may be numerous other fossils of bizarre dinosaurs that were adapted to a life in the trees awaiting discovery in Liaoning Province.  It now seems that flight evolved more than once in the Dinosauria, Yi qi was not alone and the scientific community will provide further insight in the near future with regards to the remarkable and arguably the strangest of all the dinosaurs the Scansoriopterygidae.  Such research might be hindered by the small body-size of these creatures, the Ambopteryx specimen represents a sub-adult animal, it would have measured in life around 32 cm in length and weighed just a few hundred grammes.  Epidexipteryx and Yi qi were also small, E. hui has been estimated to have measured 30 cm long and weighed less than 200 grammes, whilst Yi qi is estimated to have had a wingspan of less than 60 cm and it would have been not much heavier.  The fact that any specimens of these tiny arboreal dinosaurs have survived at all is remarkable in itself.

A spokesperson from Everything Dinosaur commented:

“Much of our knowledge about these tree-dwelling dinosaurs has been derived from fossils discovered in the last twelve years or so.  Our blog was started back in 2007 and over the course of the life of our blog we have charted the rise in the knowledge and awareness surrounding the curious Scansoriopterygidae.  There has even been a model of scansoriopterygid produced by a mainstream manufacturer.  PNSO introduced a model of Yi qi this year.  Who knows what other remarkable dinosaurs are awaiting discovery?”

The PNSO Yi qi Dinosaur Model

Yi qi dinosaur model (PNSO).

PNSO Yi qi dinosaur model.

Picture Credit: Everything Dinosaur

To read about the discovery of Epidexipteryx: Is it a Bird? Is it a Plane? No, it’s Epidexipteryx!

To read about the discovery of Yi qiYi qi The Dinosaur that Thought it was a Bat

To view the Yi qi dinosaur model and the other figures in the PNSO model range: PNSO Age of Dinosaurs

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