Catopsbaatar Kielan−Jaworowska, 1994

Kielan-Jaworowska, Zofia, Hurum, Jørn H. & Lopatin, Alexey V., 2005, Skull structure in Catopsbaatar and the zygomatic ridges in multituberculate mammals, Acta Palaeontologica Polonica 50 (3), pp. 487-512 : 489-490

Genus Catopsbaatar Kielan−Jaworowska, 1994

Type species: Catopsbaatar catopsaloides ( Kielan−Jaworowska, 1974) ; Hermiin Tsav I, Gobi Desert ( Mongolia), Red beds of Hermiin Tsav,? upper Campanian .

Revised diagnosis.— Catopsbaatar differs from other djadochtatheriid genera in having the orbit situated far posteriorly and in consequence a more elongated snout, extending for about 65 percent of the skull length. Differs from Kryptobaatar in being distinctly larger and from Djadochtatherium in being slightly larger. Differs from Djadochtatherium and Kryptobaatar in having subtrapezoidal and smaller p4 (rather than crescent−shaped), devoid of ridges, and in having only three upper premolars (P2 being lost), sharing this character with Tombaatar . Shares with Djadochtatherium a very high anterior zygomatic ridge, but differs from it in the shape of the ridge, which is semi−circular, rather than roughly trapezoidal, and in having the intermediate zygomatic ridge contacting the anterior ridge. Differs from Tombaatar in having the I3 alveolus formed exclusively by the premaxilla, rather than by both premaxilla and maxilla, and in having less prominent postpalatine torus. Differs from Djadochtatherium , Kryptobaatar , and Tombaatar in having the naso−frontal suture less pointed anteriorly in the middle. Shares with Kryptobaatar the fronto−parietal suture composed of a widely U−shaped, convex posteriorly (but relatively less deep than in Kryptobaatar ) middle part, and small lateral parts, each of which forms a U−shaped structure, situated more anteriorly than the middle part. Differs in this respect from Djadochtatherium , in which the fronto−parietal suture consists of the middle V−shaped part, narrower than the U−shaped part in Kryptobaatar and Catopsbaatar .

Distribution.—Known from the red beds of Hermiin Tsav, stratigraphic equivalent of the?late Campanian Baruungoyot Formation, localities Hermiin Tsav I and II, south−western part of the Gobi Desert, Mongolia, and from the Baruungoyot Formation at Khulsan in the Nemegt Valley.