One of the enigmatic rodent genera of the late Tertiary of China is Pararhizomys, a rare fossil taxon. One might expect that Pararhizomys, a relatively large rodent, would be found more frequently as the fossil record of China becomes better known. Although it remains poorly represented, important new material has been found, and our purpose is to make this known in the full tradition of exploration and discovery practiced by Will Downs.
Pararhizomys was named by Teilhard and Young (1931) for a peculiar jaw from the “Pontian Red Clays” of Locality 10, Chenchiangpao, Fugu County, eastern margin of Shaanxi Province. It was compared to Rhizomys, and affiliated with spalacines (represented today by the highly fossorial Spalax) at a time when Rhizomys and Spalax were generally classified together. Teilhard and Young (1931) also tentatively referred one M2 from Dalai Nor to Pararhizomys (it had been described as “Dipoides sp.” by Teilhard 1926). Young and Liu (1950) grouped Pararhizomys in the Brachyrhizomys group of Rhizomyidae. Kowalski (1968) included the genus in Rhizomyidae when he described a nearly complete skull with lower jaws from Altan Teli, Mongolia. Flynn (1982) considered Rhizomyidae to be distinct from Spalacidae and observed that Pararhizomys is possibly spalacid, but without detailed discussion. The systematic position of this genus has remained uncertain for a long time due to fossil scarcity.New fossils have been found in northern China in recent years. Two upper molars were listed as “Incertae familiae gen. et sp. indet.” from Loc. 13 of the Bahe Formation (Lantian, Shaanxi Province; Zhang et al. 2002; Qiu et al. 2003). A skull fragment without teeth is also known from this locality. A partial jaw was found from Qin’an (Gansu Province; Guo et al. 2002). During a 2003 excursion, a partial maxilla was obtained from a local farmer in Fugu County (Shaanxi Province).
The new fossil material described in this paper is housed in the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing. Measurements (in millimeters) were taken using a Wild II microscope.