Subgenus Mus. This is the mouse that constructs soil-covered storage mounds of grain, and was formally known as M. hortulanus (Corbet, 1984; Gromov and Erbajeva, 1995); however, the holotype of hortulanus is an example of M. musculus so the earliest name for the species is spicilegus (Gerasimov et al., 1990; J. T. Marshall, Jr., 1998; Zagorodnyuk, 1996b). Sympatric and frequently syntopic with M. m. musculus (Mitchell-Jones et al., 1999). Results of morphometric and allozymic analyses reported by Bonhomme et al. (1984), Petrov and Ruzic (1985), Gerasimov et al. (1990), She et al. (1990), and Lyalyukhina et al. (1991). Forms a clade with M. musculus, M. macedonicus, and M. spretus as indicated by analyses of DNA sequences from several different genes (Graur, 1994; Larizza et al., 2002; Lundrigan et al., 2002; Martin et al., 2000). Combined analyses of morphological traits, DNA/DNA hybridization, and mitochondrial 12S rRNA brings M. spicilegus together with M. spretus, M. macedonicus and M. musculus in a clade distinct from an Asian clade consisting of M. caroli, M. cervicolor, and M. cooki (Auffrey et al., 2003; Chevret et al., 2003). Other cytogenetic and biochemical contrasts between the species (reported as hortulanus) and M. musculus recorded by Bulatova and Kotenkova (1990) and Yakimenko et al. (1990). Distribution of the p53 pseudogene as another molecular trait separating M. spicilegus from M. musculus documented by Ohtsuka et al. (1996). Phylogenetic analysis of mitochondrial D-loop sequences also distinguishes M. spicilegus from M. spretus and M. musculus and indicates a separation time between M. spicilegus and M. musculus of about 3 million years ago (Flegr et al., 1994). Phylogenetic analyses of complete mtDNA cytochrome b sequences by Martin et al. (2000) clustered M. spicilegus closer to M. musculus than to M. spretus. Morphometric revision of samples from throughout the range of M. spicilegus and contrasts with M. macedonicus in the context of identifying a sample from the Adriatic coast of Serbia and Montenegro were reported by Kryštufek and Macholán (1998) who described it as a subspecies, M. s. adriaticus. In an extension of this study, the occurrence of M. spicilegus in Albania and Greece and comparison with M. macedonicus were documented in some detail by Macholán and Vohralík (1997). Sequences of APRT gene were used to illuminate substitution rate variation among M. spicelegus, M. pahari, and other muroids (Fieldhouse et al., 1997). Zagorodnyuk and Berezovsky (1994) reported aspects of taxonomy, geographic distribution, and ecology of M. spicilegus in the steppes and forest-steppes in the districts of Odessa, Nikolayev, Kirovograd, Vinnitsa, and Cherkassy districts across S Ukraine. Gromov and Erbajeva (1995) reviewed Russian segment (as hortulanus). Bauer et al. (1998), Stollmann (1998), and Stollmann and Macholán documented the Slovakian record. A four-year study of the species in Austria covering morphological traits, ecology, and population biology is reported by Unterholzner and Willenig (2000). European population reviewed by Mitchell-Jones et al. (1999).

Bauer (2000) noted that M. spicilegus is an endemic of SE Europe and, based on his review of the evolutionary time-table generated by allozymic and DNA data, speculated that the species evolved between middle and late Pleistocene near the Black Sea, possibly near the Danube delta. "M. spicilegus in SE Central Europe is so totally dependent on man-made habitats and continuous human intervention, that it well might be a rather late (neolithic or even later) immigrant" (Bauer, 2000:101). Bauer also provided an extensive review of the documented evolutionary history of this species and Mus musculus. Ellerman and Morrison-Scott (1951:608) and J. T. Marshall, Jr. (1998) listed acervator, acervifex, canicularius, and caniculator as alternative names proposed by Petényi in the same report where he described M. spicilegus; all are nomina nuda.