山西榆社晚中新世竹鼠一新种

本文描述了采自山西榆社盆地上第三系竹鼠类化石的一新种。新种与Rhizomys(Brachyrhizomyr)rhanriur相似,但个体较小,臼齿相对狭长,M,保留有连接下次尖和下次脊的齿襞(mure)及短的下中脊。这两种化石竹鼠在榆社的出现,超越了现生竹鼠类分布的北界,说明该科的情况要比以前知道的更为复杂,也表明榆社地区在晚第三纪时比近代湿润。     

Systematic revision of Siwalik Rhizomyidae (Rodentia)

Larges samples of fossil rhizomyids from the Siwalikmolasse deposits of the Potwar Plateau, Pakistan, enable reevaluation of fossil taxa and their evolutionary relationships. Siwalik Rhizomyidae constitute a basis for analysis of poorly represented rhizomyids from other areas in Asia and contribute to biochronological correlation. The extant Tachyoryctinae and Rhizomyinae diverged during the early history of the family and diagnoses of the subfamilies are amended to include extinct genera. Siwalik tachyoryctines include Kanisamys, Protachyoryctes, Rhizomyides, and Eicooryctes nov. gen.; rhizomyines are Brachyrhizomys and Anepsirhizomys nov. gen. Kanisamys, the earliest Siwalik rhizomyid, appeared by about 13 Ma and evolved slowly, displaying stasis in K. sivalensis. Brachyrhizomys evolved from Kanisamys by 9.5 Ma and radiated rapidly. B. nagrii displays rapid increase in size through time. About 7 Ma, Kanisamys and Brachyrhizomys became extinct locally and Protachyoryctes, Eicooryctes, and Rhizomyides appeared, perhaps in response to increasing aridity. After 5.5 Ma, rhizomyids became uncommon in the Potwar and Anepsirhizomys (3.0 Ma) constitutes the latest record of Rhizomyidae in Pakistan.