Bagaraatan ostromi Osmolska, 1996

Age . Maastrichtian.

Occurrence. Nemegt Formation, Omnogov, Mongolia.

Diagnosis. Mandible with two surangular foramina; anterior end of dentary almost straight and obliquely inclined dorsorostrally at an angle of approximately 55 degrees (angle between ventral and anterior margins); hyposphene-hypantrum articulations present up to the mid-tail region; anterior caudal vertebrae with subrectangular, very strongly caudally-directed transverse processes; iliac blade with large lateral depressions.

Remarks. Although only known from fragments of the lower jaw and the posterior part of the postcranium (Osmolska 1996), Bagaraatan can be clearly distinguished from other small to medium-sized dinosaurs of the Nemegt Formation by the characters listed above. Furthermore, it is one of the few theropods from the Upper Cretaceous of Mongolia that cannot readily be referred to one of the suprageneric taxa defined below, and might thus be of considerable interest.