Yi qi
Common name: Batdino Size: Pigeon sized (10cm). Age: Mid Jurassic (160 million years ago) Geographic range: China/Mongolia. Liked: Flying/gliding. Disliked: Being eaten. Taxonomy: Animalia > Chordata > Dinosauria > Theropoda>Scansoriopterygidae>Yi>qi
The Jehol and Daohugou Biota of north eastern China (see http://on.fb.me/1cViPit and http://on.fb.me/1Hnu8YF) have repeatedly stunned palaeontologists over the last couple of decades with their well preserved 160 and 130 million year old ecosystems. The time period covered by the two formations spanned the transition between feathered dinosaurs and birds, amongst other things, and the exceptional preservation of these fossilised organisms has brought us many feathers, mammalian fur and other rarities to study that are usually not preserved in fossilisation.
Yi qi comes from the older rocks of the Daohugou formation, some 160 million years old. These are the remnants of tree shaded lakes that were periodically covered in huge volumes of volcanic ash from pyroclastic flows, each killing a wide diversity of animals and shunting them into the lake beds, where the fine grained ash preserved them in near perfect detail. Only one geologically flattened partial specimen exists, the size of a medium bird that was maybe a tree dweller. The name comes from the Chinese for 'strange wing'.
Several features of its anatomy are unique. Its elongated third finger had a membrane of sliding skin and a never before seen long bony strut attached at the wrist, resulting in a bat shaped wing arrangement. Whether a newly evolved wrist bone or a ossified cartilage, the feature is very odd. The critter was a feathered therepod, whose plumes resembled quills or paintbrushes ( for an idea of what these dino feathers looked like, see my past posts of them preserved in amber, Jurassic park style, at http://on.fb.me/1DTZQdF and http://on.fb.me/1QpTFac). They were covered all over and quite dense, up to 6 cm long. Some of the bat like membrane was also preserved, and no flight feathers were present. They analysed the melanosomes for colour and found the feathers were black like a crow's and brown on the head.
The resemblance to a bat would be an example of convergent evolution, where different animals from widely varied evolutionary backgrounds take on a similar shape, such as tuna fish, dolphins (mammals) and ichthyosaurs (reptiles). It also suggests that flight evolved several times using different means in the dinosaurian and early bird lineages with maybe several groups transitioning from gliding to powered flight. It is also a transitional form between feathered dinos evolving into birds and the unrelated pterosaurs, with their more bat like wing structures. This is certainly an interesting and unusual twig on the great tree of expressed nucleic acids that we call life, and, incidentally, the dinosaur with the shortest name of all.
Loz
Image credit: graphic Dinostar Co. Ltd., photos Zang Hailong http://bit.ly/1EYblI0 http://bit.ly/1EDJFq6 http://bit.ly/1GI1QNp http://bit.ly/1GwyNXL