| Sicistine fossils from Gashunyinadege, the oldest Neogene and only known Early Miocene locality in central Inner Mongolia, include six genera ( Heterosminthus, Plesiosminthus, Litodonomys, Aplodonomys gen. nov., Rotondasminthus gen. nov., and Sicista) and nine species, including four named new species (P. vengrandis sp. nov., L. mininus, A. vexillum sp. nov., R. eknomios sp. nov.). Statistical and cladistic results indicate that (1) Heterosminthus gansus is one of the most derived species of Heterosminthus; (2) the most basal species of both Plesiosminthus and Sicista are North American; (3) however, phylogenetic analysis shows these genera to have originated in East Asia because of the phylogenetic, geographic and chronological distribution of species of the genera. Nevertheless, derived Sicista species from Eurasia may be of North American descent. |
