TWO NEW DINOSAURS OF THE INFRAORDER NEOCERATOPSIA (ORNITHISCHIA) FROM THE UPPER CRETACEOUS OF THE NEMEGT DEPRESSION, MONGOLIAN PEOPLE'S REPUBLIC

Abstract

Two neoceratopsians, Lamaceratops tereschenkoi gen. et sp. nov. and Platyceratops tatarinovi gen. ct sp. nov., from the Barun Goyot Formation (?Lower Santonian, Upper Cretaceous) of the Khulsan and Khermiin Tsav localities (Nemegt Depression, Mongolia) are described. The new genera along with Bagaceratops rozhdestvenskyi Maryańska et Osmólska, 1975 and Breviceratops kozlowskii (Maryańska et Osmólska, 1975) are assigned to the family Bagaceratopidae fam. nov. characterized by the fused nasals; the presence of the nasal horn and large subnarial fenestrae posterior to the nares between the premaxilla, maxilla, and nasal; and, probably, the development of undulating ornamentation on the surface of the egg shell. The main evolutionary stages of Asian neoceratopsians are discussed.