BAINOCERATOPS EFREMOVI, A NEW PROTOCERATOPID DINOSAUR (PROTOCERATOPIDAE, NEOCERATOPSIA) FROM THE BAIN-DZAK LOCALITY (SOUTH MONGOLIA)

Abstract

A new horned dinosaur, Bainoceratops efremovi gen. et sp. nov., is described on the basis of vertebral series from the well-known Bain-Dzak locality (Mongolia). The new form is distinguished from Protoceratops andrewsi Granger et Gregory, 1923, which is typical of Djadokhta deposits, by vertebral morphology and shows close relationships to Udanoceratops tschizhovi Kurzanov, 1992 and Leptoceratops gracilis Brown, 1914 in the following characters. The cranial surfaces of the centra of the presacral vertebrae are concave, while the caudal surfaces are flat. The diapophyses of the ninth dorsal vertebra are round in cross section, and the interprezygapophyseal spaces in this and the next vertebra are narrow. The synapophyseal facets of the posteriormost dorsal vertebra are sculptured.