Arvicolini, subtribe Arvicolina (Pavlinov et al., 1995a). Originally proposed as a subgenus of Microtus, a ranking traditionally acknowledged by Russian authors (Golenishchev and Sablina, 1991; Gromov and Erbajeva, 1995; Gromov and Polyakov, 1977; Ognev, 1964; Pavlinov and Rossolimo, 1987). In other taxonomic variations, Corbet (1978c) assigned afghanus and bucharensis, the type-species of Blanfordimys, to the genus Pitymys, and Chaline (1974) placed it in Neodon, subgenus Microtus. Ellerman (1941, 1948) considered the diagnostic traits of afghanus so impressive that he recognized the genus, an appreciation shared by many others (Ellerman and Morrison- Scott, 1951; Musser and Carleton, 1993; Pavlinov and Rossolimo, 1998; Pavlinov et al., 1995a; Zagorodnyuk, 1990).
Blanfordimys is emphasized as Allophaiomys like in retaining certain primitive traits, notably the simple M3 and m1 patterns and a high diploid number (Nadachowski and Zagorodnyuk, 1996). Allophaiomys is a late Pliocene-Pleistocene complex thought to be ancestral to Microtus and closely related genera (Chaline et al., 1999; R. A. Martin, 1995; Repenning, 1992). These primitive features, coupled with their localized ranges along the southern margin of the Palearctic arvicoline distribution, suggest that the species are Pleistocene relicts. Zagorodnyuk (1992c) even treated afghanus and bucharensis as species of Allophaiomys because the karyotype of afghanus (2n = 58) resembles that (2n = 62) hypothesized as "one of the first steps in the karyotype differentiation of Arvicolini" (Nadachowski and Zagorodnyuk, 1996:390). Although the molars of bucharensis and Allophaiomys are similar, those of afghanus are more elaborate, approaching the morphology of some Neodon (see that account). In other Holarctic regions, Allophaiomys is thought to have evolved into various subgenera of Microtus, either directly into Nearctic Pitymys and Palearctic Terricola or through a morphologically intermediate stage resembling Lasiopodomys (Chaline et al., 1999; Repenning, 1992); however, Nadachowski and Zagorodnyuk (1996) postulated a slower evolutionary rate in S Asia, those populations surviving as Blanfordimys and other Allophaiomys> like forms (also see Neodon and Phaiomys).
Blanfordimys has inflated auditory bullae and mastoid regions, the latter so enlarged that they nearly project beyond the occipital condyles and believed to be a derived configuration that occurs in no other arvicoline (Gromov and Polyakov, 1977; however, Microtus paradoxus exhibits comparable bullar and mastoidal inflation). The combination of derived (bullar and mastoid inflation) and primitive (M3 and m1 patterns) traits separates Blanfordimys from Neodon, to which it is otherwise closely similar in molar patterns (especially N. irene and N. juldaschi); from Phaiomys leucurus (also differing by its less robust cranium, longer incisive foramina, and greater variation and more elaborate configuration in M3 and m1 patterns); and from Proedromys, Lasiopodomys, and subgenera of Microtus (including Pitymys and Terricola). Generic isolation of Blanfordimys defines an explicit kinship hypothesis relative to Microtus and those other genera that should be critically tested with molecular data and an array of morphological traits, not solely molar occlusal patterns. Except for the allozymic survey of Mezhzherin et al. (1993), which nested afghanus among the 10 species of Microtus sampled, other multi-character and multi-specific inquiries are unavailable.