Darwinopterus

Darwinopterus modularis

• Liaoning (China)

Darwinopterus is a genus of pterosaur ( Pterosauria ) from the Middle Jurassic of China.

The genus was named in honor of the founder of modern evolutionary theory Charles Darwin, whose two hundredth birthday was celebrated in the scientific first description in 2009. Only species described ( type species ) of the genus is Darwinopterus modularis.

Fossil record

Fossil remains of Darwinopterus were found in the Tiaojishan Formation in Jianchang county in the Chinese province of Liaoning. The holotype with the copy number ZMNH M8782 is a skeleton well preserved with skull, jaw, an almost complete spine, a partially preserved sternum, the shoulder girdle, pelvis, a partially preserved left forelimb (wing ) and parts of the hind legs. The fossil is preserved in the Natural History Museum in Zhejiang Hangzhou in Zhejiang Province.

Another in additional to the first description Fossil is also almost complete. He only missing parts of the skull, the sternum and some finger bones. It museum in Yixian county ( Yi ) is stored in Liaoning Province under No. YH -2000 in Yizhou.

Features

Darwinopterus was a relatively small pterosaur with a long tail. The head had a length of 14 to 19 cm, the wings were 34 to 46 cm long. The skull was almost twice as long as the dorsal and sacral vertebrae together - this ratio is greater than in any other basal ( original ) pterosaurs and also for the short-tailed pterosaurs ( Pterodactyloidea ) unusual. The skull part in front of the orbit accounted for more than 80 % of the skull length of ( a derived feature of some short-tailed pterosaurs ). The foremost ( nasal ) and the antorbitale skull windows were united into a nasoantorbitalen window and incompletely separated only by a reduced bone clasp. On the skull sat a low ridge, similar to that of Germanodactylus or other Dsungaripteroidea that extended from the front end of the nasoantorbitalen window to the back of the skull. The jaws contain 15 pairs of needle-like, pointed teeth, which were far apart and the longest of which were located in the front part of the jaw.

The cervical vertebrae were extended and had short Neuralfortsätze. Cervical ribs were reduced or missing altogether. The long, stiffened tail had more than 20 vertebrae. The hind legs were characterized by a short metatarsal bones, which had less than 66 percent of the length of the femur, and five toes out, two of which were extended.

System

Darwinopterus had a long tail, is indicating in the cranial anatomy but characteristics of the short-tailed pterosaurs and is therefore regarded as a mosaic form between the original long-tailed pterosaurs and the short-tailed pterodactyls. It is the sister species of short-tailed pterosaurs and will be with them in a taxon Monofenestrata, named after the single skull window in front of the eye socket.

The systematic position of Darwinopterus illustrated by the following cladogram:

Different groups of long-tailed pterosaurs

Darwinopterus

Short-tailed pterosaurs ( Pterodactyloidea )