Tribosphenomys minutus Meng, Wyss, Dawson, and Zhai, 1994

Missiaen, Pieter & Smith, Thierry, 2008, The Gashatan (late Paleocene) mammal fauna from Subeng, Inner Mongolia, China, Acta Palaeontologica Polonica 53 (3), pp. 357-378 : 365

Tribosphenomys minutus Meng, Wyss, Dawson, and Zhai, 1994

Fig. 8 .

Referred material: 39 isolated teeth and identifiable fragmentary teeth.

Discussion.—Recently, an exhaustive study of the Alagomyidae from Subeng was published ( Meng, Ni et al. 2007), identifying three different alagomyids at Subeng: Tribosphenomys minutus , Tribosphenomys cf. T. secundus and the new taxon Neimengomys qii . Based on both morphology and size, all material collected by us is identified here as T. minutus and our observations on the dental morphology and variability of T. minutus from Subeng confirms their results. However, not a single specimen in our collections can be attributed to one of the other alagomyids reported from Subeng. This difference is possibly because our specimens were collected from a single, precise level ( Van Itterbeeck et al. 2007) which may be different than that screen−washed by Meng and co−workers, although no detailed information was published on this ( Meng, Ni et al. 2007).

Stratigraphic and geographic range.— Tribosphenomys minutus is known from the Gashatan (late Paleocene) Nomogen Formation at Bayan Ulan and Subeng and the Zhigden Member of the Naran Bulak Formation at Tsagan Khushu ( Mongolia).

Figures

Fig. 8. The alagomyid Tribosphenomys minutus Meng, Wyss, Dawson, and Zhai, 1994, from the Gashatan (Paleocene) of Subeng, China, in labial (A1–I1), occlusal (A2–I2), and lingual (A3–I3) views. A. IMM−2001−SB−036, RP4. B. IMM−2001−SB−037, LDP4. C. IMM−2004−SB−033, RM1. D. IMM− 2001−SB−035, RM2. E. IMM−2001−SB−034, RM3. F. IMM−2001−SB−038, Rdp4. G. IMM−2001−SB−039, Rm1. H. IMM−2001−SB−040, Lm2. I. IMM− 2001−SB−041, Rm3. SEM micrographs.