Chinese dinoboffins have announced the discovery of one of the oddest creatures that may have ever attempted flight. The critter lived during the Jurassic Period, about 160 million years ago, 10 million years before the appearance of the first bird.
The pigeon-sized reptile, named Yi qi ("E-chee") or Strange Wing in Mandarin, is reckoned to be a cousin of modern birds. Its bat-like wings are made of membranous skin, rather than feathers, just like the wings of the extinct flying reptiles known as pterosaurs, of which it is a contemporary but not a relative.
The discovery was announced on Wednesday in a study published in Nature, titled "A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings."
The study says that Yi qi's fossil suggests it had wings that are unique among dinosaurs. As the abstract explains, "documentation of the unique forelimbs of Yi greatly increases the morphological disparity known to exist among dinosaurs, and highlights the extraordinary breadth and richness of the evolutionary experimentation that took place close to the origin of birds."
Each of Yi's wings was supported by a clawed, three-fingered hand, one finger considerably elongated, and a rod-like bone which extended from the wrist. Downy feathers preserved around its head, neck and limbs have been recognised as more similar to hairs or bristles than to the feathers birds utilise in flight.
The dinoboffins' conclusions, however, were immediately challenged: "Things have just gone from the strange to the bizarre," University of California biologist Kevin Padian stated, in a comment carried by Nature.
"To fly actively, an animal must be able to execute a flight stroke that can generate a vortex wake that propels it forward," he said, adding that "no evidence presented so far suggest that Yi qi had this ability."
In their supplementary notes, however, the dinoboffins are adamant about their findings, all but challenging Padian to find a "case in which a long, unjointed bony or cartilaginous rod extending from a limb joint has evolved in any vertebrate without being associated with an aerodynamic membrane," noting that "plausible alternative functions for such a structure are difficult to conceive."
Nature editor Henry Gee, a palaeontologist and evolutionary biologist, said a feathered dinosaur with a wing membrane "is not something anyone would ever have expected to find."
Yi qi is known only from a single fossil, which a farmer found in a quarry in the Chinese province of Hebei. The fossil was purchased by the Shangdong Tianyu Museum of Nature, whose staff uncovered many of the unique features and soft tissues of the specimen during preparation, rather than via the amateur fossil seller, and as such were confident that it was authentic and unaltered.
It should be noted that it is the dinoboffins' conclusions, and not the fossil's unusual qualities, which have attracted scepticism. Henry Gee stated that he expected the paper "will cause a great deal of flap." ®