New Craniodental Materials of Litolophus gobiensis (Perissodactyla, ‘‘ Eomoropidae’ ’) from Inner Mongolia, China, and Phylogenetic Analyses of Eocene Chalicotheres Author Bai, Bin Author Wang, Yuanqing Author Meng, Jin text American Museum Novitates 2010 2010-06-25 3688 1 28 http://www.bioone.org/doi/abs/10.1206/678.1 journal article 4582 10.1206/678.1 2c2b274c-b210-4946-a69d-723bd4e960d6 0003-0082 5358869 LITOLOPHUS GOBIENSIS (Colbert) , 1934 HOLOTYPE : AMNH 26645 . A crushed skull and a mandible, probably belonging to the same individual ( Colbert, 1934 ). PARATYPES : AMNH 26644 , 26646–26649 , 26653–26659 . Skulls , mandibles, forefeet and hind feet found in a small quarry, 6 miles west of Camp Margetts , Inner Mongolia . REFERRED SPECIMENS: IVPP V16139 , a relatively well-preserved skull with right P2– M3 and left C–M3; V16140 -1, a greater part of right side of a skull with P1–4 and M3; V16141 -1, a posterior portion of a skull with right P2–M1, M3 and left P2–4, M2–3; V16141 -2, a right side of the anterior portion of a skull; V16142 , a dorsoventrally compressed subadult skull with P2–M3; V16143 , a fragmentary premaxilla with I3; V16144.1, a right I2; V16144.2, a left I2; V16144.3, a left I2; V16144.4, a right I3; V16147 , a subadult mandible with right p3–m3 and left i1, p2–m3; V16148 , a partial subadult left lower mandible with p3–m3 and two i1s; V16149 , a nearly complete mandible with c–m3; V16150 , a nearly complete mandible with p2–m3; V16167.1, a right i2; V16167.2, a right i2; V16167.3, a right i2; V16167.4, a left i3; V16167.5, a left i3. EMENDED DIAGNOSIS: Medium-sized chalicotheres with low-crowned teeth; dental formula 3 ? 1 ? 4 ? 3/3 ? 1 ? 3 ? 3; a short diastema present between P1 and P2; P3–4 metalophs joining the ectolophs in a low position, and paraconules usually well developed; upper molars with prominent parastyles and paraconules, but lacking mesostyles; paracones and metacones on upper molars nearly vertically implanted, protocones posteriorly extended, and metalophs oblique and relatively short; M3 metaloph and metacone posterobuccally rotated; lower molar cristid obliqua anterolingually directed to the buccal sides of the ‘‘metastylids,’’ and the hypolophids oblique; posterior cingulids on m1–2 raised upward but lacking the cuspate hypoconulids; m3 with a well-developed hypoconulid lobe; parietal crests gently contracted behind postorbital processes; supraorbital foramen absent; paroccipital process slender and completely separated from the relatively broader and larger posttympanic process; posterior border of the palate nearly U-shaped at the level of posterior edge of M3; ventral surface of the promontorium smooth; deep fossa for the stapedius muscle present; mandible long and slender, with long shallow symphysis and high ascending ramus; angular process of the mandible with a nearly semicircular border. LOCALITY AND HORIZON: Nuhetingboerhe, Erlian Basin, Inner Mongolia , China . Lower part of the Arshanto Formation; early Arshantan (Early Eocene).