Forstercooperia ulanshirehensis, sp. nov.

HOLOTYPE: A nearly complete cranium (AMNH 21608) (figs. 2–4).

REFERRED SPECIMENS: A pair of complete mandibles (IVPP V20155) (figs. 5, 6), a fragmentary maxilla with P3–M3 (IVPP V20154) (figs. 7A, 7B); a fragmentary mandible with the lower canine and p1–4 (IVPP V20156) (figs. 7C, 7D), and a fragmentary mandible with p3–m3 (AMNH 22101) (fig. 8).

a Approximate measurements.

ETYMOLOGY: The specific name ulanshirehensis refers to the Ulan Shireh Formation, in which AMNH 21608 was collected.

HORIZON AND LOCALITY: AMNH 21608 (field number, 613), Ulan Shireh Formation, Wulanhuxiu site (previously known as 8 miles north of Tukhum Lamasery) of Erlian Basin, Nei Mongol, China; AMNH 22101 (field number, 602), Ulan Shireh Formation, Wulantaolegai site (previously known as 4 miles north of Tukhum) of Erlian Basin, Nei Mongol, China; IVPP V20154, V20155, and V20156, Irdin Manha Formation, Irdin Manha site, Erlian Basin, Nei Mongol, China. Middle Eocene.

DIAGNOSIS: Small species of Forstercooperia, the length of upper premolar series about 81 mm, about 25% smaller than that of Forstercoopeia totadentata (~ 108 mm), about 20% smaller than that of Forstercooperia mazhuangensis (~ 103 mm) (see appendix, tables 2–3). Upper premolars transversely slightly narrower. Protocone and hypocone of P2 barely separate, metaloph of P2 narrow and posterolingually oriented. Metalophs (metaconules) of P3–4 short. Entoconid of p4 present.