IGM

IGM may refer to:

Medicine

Citipati

Citipati (pronounced [ˈtʃiːt̪ɪpət̪i] in Hindi, meaning 'funeral pyre lord') is a genus of oviraptorid theropod dinosaur from the Late Cretaceous Period of what is now Mongolia (specifically, the Djadokhta Formation of Ukhaa Tolgod, in the Gobi Desert). It is one of the best-known oviraptorids, thanks to a number of well-preserved skeletons, including several specimens found in brooding positions atop nests of eggs. These nesting specimens have helped to solidify the link between non-avian dinosaurs and birds.

The type species, Citipati osmolskae, was described by James M. Clark, Mark Norell, and Rinchen Barsbold in 2001. A second, as yet unnamed species may also exist. Citipati is often confused with the similar Oviraptor.

Description

The largest Citipati were emu-sized animals and, at about 3 meters (10 ft) long, were the largest known oviraptorids until Gigantoraptor was described in 2007. Like other oviraptorids, Citipati had an unusually long neck and shortened tail, compared to most other theropods. Its skull was unusually short and highly pneumatized (riddled with openings in the bone structure), ending in a stout, toothless beak. Perhaps the most distinctive feature of Citipati was its tall crest, superficially similar to that of a modern cassowary. The crest was relatively low in the type species, C. osmolskae, with a nearly vertical front margin grading into the beak. In contrast, the crest of one referred specimen which has not yet been assigned a specific name (provisionally labeled C. sp.) was taller, with a prominent notch in the front margin, creating a squared appearance.

Byronosaurus

Byronosaurus is a genus of troodontid dinosaur from the Late Cretaceous Period of Mongolia.

Discovery and naming

In 1993, Michael Novacek, a member of an American Museum of Natural History expedition to the Gobi Desert, discovered the skeleton of a small theropod at Ukhaa Tolgod. This was further excavated in 1994 and 1995. The find was illustrated in a publication in 1994. On 15 July 1996, at the Bolor's Hill site, about eight kilometers (five miles) away from the original location, a second specimen was discovered, a skull.

In 2000, Mark Norell, Peter Makovicky and James Clark named and described the type species Byronosaurus jaffei. The species name as a whole honoured Byron Jaffe, "in recognition of his family's support for the Mongolian Academy of Sciences-American Museum of Natural History Paleontological Expeditions".

The holotype, IGM 100/983, was found in a layer of the Djadochta Formation dating from the late Campanian. It consists of a partial skeleton with skull. It contains a partial skull with lower jaws, three neck vertebrae, three back vertebrae, a piece of a sacral vertebra, four partial tail vertebrae, ribs, the lower end of a thighbone, the upper ends of a shinbone and calf bone, a second metatarsal and three toe phalanges. The paratype, specimen IGM 100/984, is the skull found in 1996, of which only the snout has been preserved. Both specimens are of adult individuals.