Order Rodentia - Family Muridae Author Wilson, Don E. Author Reeder, DeeAnn text 2005 The Johns Hopkins University Press Baltimore Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 2 1189 1531 book chapter 0-8018-8221-4 10.5281/zenodo.7316535 Micromys Dehne 1841 Micromys Dehne 1841 , Micromys agilis, Ein Neues Saugetier der Fauna von Dresden : 1 . Type Species: Micromys agilis Dehne 1841 Species and subspecies: 1 species: Species Micromys minutus ( Pallas 1771 ) Discussion: Micromys Division. Generic diagnosis based upon molar traits provided by Storch (1987) . Molar morphology indicates a close relationship with members of Misonne’s (1969) Progonomys group (within a more inclusive Lenothrix-Parapodemus Division), and phylogenetic relationships assessed by microcomplement fixation of albumin ( Watts and Baverstock, 1995 b ) pointed to the Asian Vandeleuria (also a member of Misonne’s Progonomys cluster) as the closest living relative of Micromys , an alliance hinted at by Jüdes’s (1981) interpretation of chromosomal data, and explicitly indicated by Ellerman (1949:132) based upon morphology. Phylogenetic analyses of complete mtDNA cytochrome b sequences by Martin et al. (2000) could not resolve the phylogenetic position of Micromys relative to other murines and deomyines sampled ( Apodemus , Mus , Rattus , Acomys ), nor could analyses of sequences from the nuclear LCAT ( Robinson et al., 1997 ); neither of these studies included Vandeleuria . Micromys possesses a quality of the Lx family of long interspersed repeated DNA compared with other extant murines sampled ( Mus , Praomys , Rattus , Bandicota , Arvicanthis , Mastomys , Hylomyscus , Aethomys , Dasymys , and Apodemus ) that indicates it to be the most divergent of those genera and an outgroup to them ( Furano et al., 1994 ). Those authors speculated that Micromys diverged early from the core murine lineage, an observation consistent with scnDNA hybridization data ( Catzeflis et al., 1992 ), analyses of sequences from nuclear IRBP gene, and mtDNA cytochrome b and 12S rRNA ( Michaux et al., 2002 a ), and the early presence of the genus and phylogenetic history in the Neogene. Micromys may have been the first lineage to have diverged from a common ancestral Progonomys like form approximately 12 million years ago ( Furano et al., 1994 ). Based upon her cladistic analysis of molar traits, Chaimanee (1998) suggested the Indomalayan Vandeleuria , Lenothrix , and Pithecheir are also members of this primary divergent lineage. The early evolutionary origin of Micromys is reflected in its phylogenetic history documented by fossils representing ten extinct species: one from the late Miocene of Nei Mongol ( Storch, 1987 ), seven from the late Miocene, Pliocene, and Pleistocene of Europe, one of which occurs in Europe and Nei Mongol ( Qiu and Storch, 2000 ; Weerd, 1979 ; see Storch and Dahlmann, 1995 , who reviewed all the fossil species of Micromys ), one from the early to late Pliocene of S China ( Cai and Qiu, 1993 ; Wu and Flynn, 1992 ), and another from the early Pleistocene of S China ( Zheng, 1993 ). "The fossil Micromys species do not represent a single lineage which finally leads to the living M. minutus .... the genus underwent radiations and shows a rather complex phylogenetic history" ( Storch and Dahlmann, 1995:128 ). Only one living species is recognized by most workers, but whether extant samples represent one or more species has yet to be resolved by critical systematic revision .