Mahakala (dinosaur)
Skeletal reconstruction of Mahakala omnogovae, above the known skeletal parts.
- Mongolia ( Djadochta Formation)
- Mahakala omnogovae
Mahakala is a genus theropod dinosaur from the group of Dromaeosauridae. So far, a fragmentary skeleton is only known that was discovered in the Gobi Desert in Mongolia and about 80 million years old is ( Upper Cretaceous, Campanian ). The only way Mahakala omnogovae, was founded in 2007 by Turner et al. described. Mahakala was about 70 cm length and a very small basal (original ) Representatives of Dromaeosauridae.
Features
Mahakala was a very small theropod - as is the thigh bone ( femur), which is particularly important for size estimates, only 80 mm long. The life of the animal's weight is estimated to be about 700 g. Despite the small size of the specimen found died in young adulthood, after which the degree of fusion of the vertebrae, the ankle, the skull and histological analysis suggests. The tail was very long, similar to basal birds, basal troodontids and other Dromaeosauriden. Mahakala had probably disproportionately large eyes - like troodontids, but unlike other Dromaeosauriden. As a Dromaeosauride Mahakala showed the typical enlarged sickle-shaped claw on the second toe.
Three features have been described, where the genus can be clearly distinguished from other genera ( autapomorphies ): So the ulna ( ulna ) was highly compressed, broadly along the body axis and pointed forward in a thin edge to. The femur showed a longer lateral ridge in posterodistalen area. They also demonstrated the posterior caudal vertebrae subhorizontal, laterally aligned prezygapophyses ( connecting elements of the vertebrae).
System
Phylogenetic studies of Turner et al. show that it was a basal ( original ) Dromaeosauriden at Mahakala. Thus, this species shows features that are also found in early birds and troodontids but absent in other Dromaeosauriden. Mahakala was similar small as the basal bird Archaeopteryx, the basal Oviraptorosaurier Caudipteryx or the basal Troodontide Mei. From this, the researchers conclude that a small body size was not only trained by the birds, but that even the common ancestor of Deinonychosauria and the birds were small. The common ancestor of all Paraves ( Deinonychosauria and birds) had according to the researchers probably has a length of about 65 cm and a weight of 600 to 700 g In the evolution of Deinonychosauria in different lineages but several times a radical growth in size by up to three orders of magnitude occurred.
Fund and naming
The only Fund ( holotype, specimen number IGM 100/1033 ) consists of a fragmentary skull with Postkranium and was discovered in Tugrugyin Shireh in the Mongolian Gobi Aimag Ömnö. Today the remains are kept in the Mongolian Institute of Geology in the Mongolian capital of Ulan Bator. Stratigraphically the Fund comes from the Tugrugyin - layer member of Djadokhta Formation ( Campanian ).
The genus name is derived from Sanskrit and is known by Mahakala, one of the eight guardian deities of the Buddha's teaching ( Dharmapala ) in Tibetan Buddhism. The Artepitheth omnogovae refers to the locality in the southern Gobi Desert.