916 



EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



Locality, identification, and character of remains of 27 skulls, jaws, and other parts of sTceletons of titanotheres col- 

 lected from the Shara Murun formation (uppermost Eocene) near the locality Via Usu, on the Kalgan- Uliassutai 

 trail, in southeastern Gobi, Mongolia 



[After field catalog and notes of Walter Granger] 



Character of remains 



Dolichorhinus kaiseni Osborn, type 



Dolichorhinus kaiseni, paratype 



Dolicliorliinus kaiseni , referred 



Do 



Protitanotherium mongoliense Osborn, type 



Protitanotherium mongoliense, neotype . 



Protitanotlierium mongoliense, referred 



Do 



Do 



Do 



Protitanotherium andrewsi Osborn, type 



Protitanotherium andrewsi, paratype 



Protitanotherium andrewsi, referred 



Do 



Do 



Do 



Do 



Not determined (pro-Menodus mongoliensis phy 

 lum?). 



Not determined 



Do 



Not determined (Protitanotherium?) 



Protitanotherium andrewsi?, referred 



Not determined (Protitanotherium) 



Protitantherium mongoliense, referred 



Not determined (Protitanotherium?) 



Protitanotherium mongoliense, referred 



Protitantotherium andrewsi, referred 



20252 Male skull and jaws; nearly complete dentition. 



20257 Palate and basicranium; complete dentition. 



20255 Female skull and jaws; nearly complete dentition. 



20260 Male skull and jaws; complete dentition. 



18653 Right ramus, fragment, with 6 grinding teeth. First titanothere 



to reach American Museum from Mongolia. 



20263 Palate and dentition nearly complete. 



20256 Palate, canine, superior grinders, lower jaws. 



20261 Female skull complete but crushed; incisors, canine, grinders. 



20270 Right maxilla and zygoma; superior grinders. 



20273 Fine pair of jaws, lacking symphysis; inferior grinders. 



20271 Complete male skull and dentition; nasals wanting. 

 20251 Male? Left ramus; inferior grinders. 



20254 Male skull; superior dentition. 



20262 Jaws; symphysis, upper incisors, and grinders. 

 20269 Symphysis of jaws with canines. 



20280 Juvenile palate, deciduous premolars, first and second molars. 



20272 Fine jaw, male; inferior dentition. 



20253 Premaxilla, incisor; ulna, femur, several vertebrae and foot bones. 



20265 Maxilla fragment. 

 20268 i Left ramus of lower jaws. 



20258 ' Fore foot, with distal end of ulna and radius. 



20259 Part of fore foot (metapodials) . 

 20267 I Associated foot bones. 



20274 Incomplete hind foot. 



20275 Fore and hind foot bones. 

 20276 



20277 Complete hind limb and foot. 



20327 Right humerus, 2 right tibiae, left tibia, miscellaneous foot bones. 



Locality, identification, and character of teeth, jaws, and slcull collected from the Ardyn Oho formation (lower Oligo- 

 cene) on the Kalgan- Uliassutai trail, southeastern Gobi, Mongolia 



[After field catalog and notes of Walter Granger] 



Character of remains 



Crushed skull, collected July 2, 1923. 



Symphyseal region of lower jaw, collected June 30, 1923. 



Part of lower grinding tooth, collected June 29, 1923. 



Brontops gobiensis Osborn, type 



Brontops gobiensis, referred 



Menodus mongoliensis Osborn, type 



GENERIC AND SPECIFIC CHARACTERS OF THE 

 MONGOLIAN TITANOTHERES 



Next to the discovery of titanotheres in Mongolia 

 the most gratifying feature of the results of the explo- 

 ration is that all the species thus far found belong to 

 genera similar to those previously discovered in the 

 Rocky Mountain region of North America. This 

 generic affinity enables us to establish four or perhaps 

 five lines of titanothere migration between central 

 Asia and North America. These genera, named in 

 ascending or progressive order of evolution, are as 

 follows : 



Lower Oligocene Brontops of the Ardyn Obo formation; 

 extremely broad-headed, similar to the Brontops of South 

 Dakota. 



Lower Oligocene Menodus of the Ardyn Obo formation; long- 

 headed, somewhat similar to the Menodus giganteus of South 

 Dakota. 



Upper Eocene Protitanotherium of the Irdin Manha and Shara 

 Murun formations; a large animal, similar to the Protitano- 

 therium of the Uinta formation of Utah. 



Telmatherium of the Irdin Manha formation; long-headed, 

 deep-jawed, similar to the Telmatherium of the Bridger and 

 Uinta formations of Wyoming and Utah. 



Dolichorhinus of the Irdin Manha and Shara Murun forma- 

 tions; the "long-nosed" titanothere, similar to the Dolichorhinus 



