RECONSIDERATION OF THE GENERIC ASSIGNMENT OF“"PLIOPENTALAGUS NIHEWANENSIS” FROM THE LATE PLIOCENE OF HEBEI, CHINA

"Pliopentalagus nihewanensis" was described by Cai (1989) , based on an isolated p3 and two isolated lower molariform teeth from the bottom of the "Nihewan beds" of Hebei Province, China. Detailed re-examination of the original specimens and comparisons with other species of the genus and Trischizolagus suggest: 1) the holotype (p3) alone can be interpreted as a species of the genus Pliopentalagus having p3 with least complicated enamel pattern. But, this hypothesis violates an evolutionary trend of the genus that the enamel pattern becomes more complicated through time. On the other hands, 2) the holotype can also be interpreted as a species of the genus Trischizolagus having p3 with most complicated enamel pattern. This hypothesis fits on an evolutionary trend of the genus that enamel pattern becomes more complicated through time ( Averianov and Tesakov, 1997) , 3) the associated fauna which is indicative of a dry and cool environment also suggests that the holotype may not belong to the genus Pliopentalagus. Therefore, we conclude that generic assignment of this taxon should be Trischizolagus, and T. nihewanensis is characterized by p3 with most complicated enamel pattern within the genus.