Tsagantegia

Tsagantegia (; meaning Tsagan Teg) is a genus of medium-sized ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous period. The genus is monotypic, including only the type species, T. longicranialis. The specimen consists of a very partial individual, comprising the skull and lacking postcranial remains. Since it only preserves the skull, Tsagantegia is mainly characterized by its elongated snout and the flattened facial osteoderms, greatly differing from other ankylosaurs. Discovery and naming The holotype specimen, MPC 700/17, is a virtually complete skull that was recovered from the locality Tsagan-Teg (or "White Mountain") of the Bayan Shireh Formation in the southeastern Gobi Desert, Mongolia. It was formally described in 1993 by the Russian paleontologist Tatyana Alekseyevna Tumanova. The generic name, Tsagantegia, is in reference to Tsagan Teg, the locality of its discovery, and the specific name, longicranialis, is derived from the Latin words and , in reference to its elongated skull. Description Tsagantegia was a medium to large-sized ankyosaur, with an estimated length of and weighing about . The skull measures about in length, with a near width of , missing the lower jaws. Unlike other Asian ankylosaurs, in Tsagantegia the caputegulae (cranial ornamentation) are not subdivided into a mosaic of polygons but are amorphous and flattened; they show some degree of symmetry. The quadratojugal, squamosal and orbital horns are poorly preserved, in contrast with other ankylosaurs. The snout was long and flat with a pointed rostrum (beak); each maxilla preserves approximately 18 alveoli, no teeth were preserved. According to Arbour, Tsagantegia differs from Gobisaurus and Shamosaurus based on the more rounded, U-shaped premaxillary beak and the flat ornamentation.