Apodemus Kaup, 1829 . Skizz. Entwickel.-Gesch. Nat. Syst. Europ. Thierwelt, 1:154.

TYPE SPECIES: Mus agrarius Pallas, 1771 .

SYNONYMS: Alsomys, Karstomys, Nemomys, Petromys, Sylvaemus .

COMMENTS: Palaearctic species reviewed by Corbet (1978c, 1984) and Kobayashi (1985), Chinese species by Xia (1984, 1985). Recognized species have been allocated among the subgenera Apodemus, Sylvaemus, Alsomys, and Karstomys (Corbet, 1978c; Zimmermann, 1962) but whether these names designate monophyletic clusters and should be retained as subgenera or instead raised to generic rank remains to be answered by critical systematic revision of the entire group, which is currently unavailable. Most taxonomists recognize at least the subgeneric validity of Apodemus and Sylvaemus; some suggest Sylvaemus should be raised to generic rank because of its great morphological and genic divergence from Apodemus (Britton-Davidian et al., 1991; Mezhzherin and Zykov, 1991); others treat Sylvaemus as a separate genus (Bonhomme et al., 1985; Mezhzherin and Lashkova, 1992). Phallic morphological comparisons among five European species provided by Williams et al. (1980) and among Chinese species documented by Yang and Fang (1988). Taxonomic differences in testes size among European species documented by Kratochvil (1971). Comparative chromosomal studies among European species provided by Soldatovic et al. (1975), Bekasova et al. (1980), and Vujosevic et al. (1984); chromosomal contrasts among Japanese species presented by Tsuchiya (1981). Electrophoretic variations of enzymes among species of Apodemus documented by Darviche et al. (1979, and references cited therein), Gemmeke (1980), Gill et al. (1987), and Fraguedakis-Tsolis (1983) in systematic context; electrophoretic, karyological, and morphological distinctions among several species reported by Vorontsov et al. (1989) and Britton-Davidian et al. (1991). Differences in restriction endonuclease of nuclear DNA from three Austrian species reported by Csaikl et al. (1990). DNA-DNA hybridization results from analyses of three species presented by Catzeflis et al. (1987) and Catzeflis (1990). Numerous taxonomic provincial studies described morphological and other distinctions among sympatric species of Apodemus; examples are the study of five species from Bulgaria by Popov (1981), three species from Poland by Ruprecht (1979), and two species from Korea by Koh (1988) and Park et al. (1990). Vorontsov et al. (1989) described the presence of five species in the Caucasus, some of which were distinguished only by biochemical traits; Vorontsov et al. (1992) recently identified and defined four species from there. Tchernov (1979) reported on polymorphism, size trends and Pleistocene paleoclimatic responses of three Israeli species in an evolutionary context.