Mus (Mus) terricolor Blyth 1851

Mus (Mus) terricolor Blyth 1851, J. Asiat. Soc. Bengal, 20: 172.

Type Locality: S India, Bengal, neighborhood of Calcutta.

Vernacular Names: Earth-Colored mouse.

Synonyms: Mus (Mus) beavanii Peters 1866; Mus (Mus) dunni Wroughton 1912 .

Distribution: Indigenous to peninsular India and Nepal (J. T. Marshall, Jr., 1998), Bangladesh (Comilla District, Chittagong Province; Alpin et al., 2003 c; K. Alpin, in litt., 2004), and Pakistan (J. T. Marshall, Jr., 1998); occurs also in Medan region of N Sumatra (Indonesia) where it was probably inadvertently introduced (Musser and Newcomb, 1983, recorded as dunni).

Conservation: IUCN – Lower Risk (lc).

Discussion: Subgenus Mus . Formerly referred to as M. dunni (J. T. Marshall, Jr., 1977 b, 1986), but terricolor is the older name (J. T. Marshall, Jr., 1977 b, 1998:80, and in litt., 1989). Chromosomal results presented by Sharma et al. (1986, under dunni) and Boyeskorov et al. (1997, as dunni) in context of evolutionary divergence from other species of Mus . Closely related to Mus booduga . Both species have 2n = 40, with all telocentric chromosomes, but M. booduga has a slightly smaller Y chromosome. All populations sampled show the same karyotype; M. terricolor, however, has a large submetacentric X and telocentric Y. Furthermore, different populations of M. terricolor have three different karyotypes (formally labelled I, II, and III) indicating various stages of evolutionary differentiation in which heterochromatin may be important in the speciation process (Bahadur and Sharma, 1995; Sharma et al., 2002). In a combined chromosomal and molecular study (allozymes, serum proteins, and mitochondrial cytochrome b DNA sequences), Sharma (1996) concluded the M. booduga-M. terricolor lineage probably evolved simultaneously with the M. caroli-M. cookii-M. cervicolor lineage and M. terricolor itself is in an active phase of speciation. Balajee and Sharma (1994) found M. musculus like AT-rich heterochromatin in M. booduga and the three chromosomal forms of M. terricolor . Patnaik et al. (1993) contrasted dental traits and cranial features between M. booduga and M. terricolor and compared dental patterns of those two with molars of six species of Mus represented by late Pliocene-Early Pleistocene fossils from the N portion the Indian subcontinent, concluding that the fossil Mus are dentally closely related to the extinct species and reflect an early diversification in the evolutionary history of the genus. The multivariate morphometric analysis by Macholán (2001) suggested M. terricolor to be distantly related to the two other species in subgenus Mus that were examined, M. caroli and M. cervicolor . Occurrence and ecology of M. terricolor in the Aravalli ranges of Rajasthan State documented by Prakash et al. (1995 a, b, c), and in Gujarat State, NW India by Chakraborty and Agrawal (2000). The Bangladesh record was confirmed from comparisons with Indian and Nepalese samples using DNA sequences, all of which were very similar (K. Aplin, 2004).