Sylvaemus group. Geographic variation of E European samples in the context of testing correlation between phenotypic and genotypic variations of certain morphological characters documented by Orlov and Okulova (2001). Additional research using a variety of data sources that provide comparative information among populations of A. flavicollis are: B chromosome polymorphism among populations (Vujosevic et al., 1991), and presence or absence of B chromosomes and the attendant biological significance (Blagojevi and Vujoševi, 1995; Macholán and Zima, 1997; Ramalhinho and Libois, 2002; Vujoševi and Blagojevi, 1995, 2000; Zima et al., 1999a, 2003); chromosomal morphologies of Macedonian (Zima et al., 1997a) and Baltic (Boyeskorov et al., 1992) samples; genetic variation in a fluctuating Polish population (Wójcik, 1993); and mtDNA cytochrome b haplotype divergence among W European samples (Reutter et al., 2003). Phylogeographic history (using mtDNA cytochrome b sequences) of A. flavicollis in Europe and the Near and Middle East in the context of determining Quaternary glacial refugia and postglacial recolonization events reported by Michaux et al. (2004b).
Contrasts and similarities between A. flavicollis and A. sylvaticus are available based upon: chromosomal morphology, allozymic variation, and mitochondrial and nuclear DNA sequences (Bellinvia et al., 1999; Britton-Davidian et al., 1991; Chelomina, 1998; Chelomina et al., 1998a, b; Debrot and Mermod, 1977; Filippucci, 1992; Filippucci et al., 1996, 2002; Gemmeke, 1980, 1981b; Hirning et al., 1989; Macholán et al., 2001b; Michaux et al., 2002a, 2004a]; Mezhzherin, 1997a; Mezhzherin and Zykov, 1991; Mezhzherin et al., 1992; Nadjafova et al., 1993; Orlov et al., 1996a, b; Reutter et al., 2003; Serizawa et al., 2000; Suzuki, et al., 1990; Tegelstrom and Jaarola, 1989); genetic structure of populations living in four different biotypes (Amori et al., 2002b); morphometric analyses, in context of evolutionary divergence, morphometric identification, and habitat selection (Amori and Contoli, 1994; Dolan and Yates, 1981; Feiler and Tegegn, 1998; Fernendes et al., 1991; Fielding, 1966; Hedges, 1969; Kryštufek and Stojanovski, 1996; Mezhzherin and Lashkova, 1992; Nores, 1988; Panzironi et al., 1993; Popov, 1993; Van der Straeten, 1976b; Van der Straeten and Van der Straeten-Harrie, 1977); dental variation (Filippucci et al., 1996; Tvrtkovi, 1976); temporal variation of non-metric traits (Sádlová and Frynta, 2001); and habitat in Norway (Lura et al., 1995). Differences in blood serum proteins between A. flavicollis and A. witherbyi (reported as hermonensis) documented by Verimli et al. (2000). Based on allozyme and chromosome data, Orlov et al. (1996a, b) placed A. flavicollis and A. ponticus in the superspecies A. flavicollis. The species was a part of Mezhzherin’s (1997a) revision of N Eurasian Apodemus based upon morphology and molecular data.
The inclusion of arianus, along with erythronotus (the name arianus replaced; see Kryštufek, 2000), in the above synonymy follows Kryštufek’s (2002a) identification of the holotype. Musser and Carleton (1993) had used arianus as the oldest name for the species we now list as A. witherbyi (see that account). The taxon stankovici, described by Martino and Martino (1937) as a subspecies of A. sylvaticus from the Korab Mtns of W Macedonia, was treated as an endemic Balkan species by Petrov (1993/94), who considered A. flavicollis and A. stankovici to be narrowly sympatric but found in different habitats. In Petrov’s view, the range of A. stankovici would be concordant with other mammalian Balkan relicts, such as the vole, Dinaromys bogdanovi, and the mole, Talpa stankovici. However, morphometric analysis of SW Balkan samples of A. flavicollis and A. sylvaticus along with the holotype and paratypes of stankovici by Kryštufek and Stojanovski (1996) demonstrated the conspecificity of the latter with A. flavicollis. There may be another species (in addition to A. flavicollis and A. sylvaticus) in the SW Balkan Mtns, but it is not stankovici (B. Kryštufek, 2002, in litt.).
Bate’s (1942b) levantinus, based upon Palaeolithic specimens from Israel and described as a species morphologically similar to A. flavicollis (see expanded description in Tchernov, 1968), is now regarded as synonymous with A. flavicollis (Tchernov, 1986) and documents the evolutionary history of the species, which now lives in Israel, back to early Pleistocene in that country (see also Tchernov, 1996).
European populations reviewed by Niethammer (1978b) and Mitchell-Jones et al. (1999). Among the numerous regional reports detailing geographic range, taxonomy, habitat, and other biological aspects of A. flavicollis are the following more recent contributions for: Norway (Lura et al., 1995); Netherlands, where the species is known only from the southern tip (Bergers and Foppen, 1992; Thissen and Hollander, 1996); Belgium (Libois, 1996; Van der Straeten, 1976b); Germany (Alf et al., 1997; Berger and Feldmann, 1997; Dolch et al. 1994; Niedenführ and Rathke, 1996); Austria (Bauer and Spitzenberger, 1969); Switzerland (Hausser, 1995; Maurizio, 1994); Slovakia (Danko, 1994; Kminiak, 1996; Mošanský, 1994; Stanko, 1995; Stanko and Mosansky, 1994, 2000; Stanko et al., 1994, 2000); Czech Republic (AndŤra and ervený, 1994; Šmaha, 1996; Zima and AndŤra, 1996); Translvanian Romania (Istrate, 1998); Bulgaria (Chassovnikarova and Markov, 1999; Peshev, 1996); Italy (Amori et al., 1999, 2002a, b; Cagnin et al., 1996; Cantini, 1991; Cerone and Aloise, 1994; Cresti et al., 1992; Locatelli and Paolucci, 1996a); E Baltic region (Miljutin, 1997, 1998; Timm et al., 1998); Lithuania (Juškaitis and Baranauskas, 2001); Serbia and Montenegro (Petrov, 1992); Slovenia (Kryštufek, 1991); Albania (Prigioni, 1969); SE Greece (Thrace; Vohralík, 1992); Turkey (Kryštufek and Vohralík, 2001); Armenia (Gromov and Erbajeva, 1995); and Israel (Qumsiyeh, 1966). USNM 369845, a young adult from Kordestan Province (near Marivan), Zagros Mtns, is one of the few records of A. flavicollis from Iran, where the species has been recorded only in the Zagros Mtns. It was taken at the same place on the day before USNM 369846, an A. witherbyi, was collected. The two species in Iran are regularly misidentified in museum collections. Iranian A. flavicollis has paler dorsal pelage than Turkish samples, whitish gray underparts (white in A. witherbyi), a round pectoral patch (streak in A. witherbyi), molar occlusal patterns that are typical of Turkish A. flavicollis (Filippucci et al., 1996), M1-3 length = 4.2 mm (usually less than 4.0 in A. witherbyi), and large bullae (5.2 mm; 4.2-4.8 mm in USNM Iranian A. witherbyi, usually 4.5 mm).
From 1948 (following Heptner, 1948) until the 1990s, some authors (e. g., Ondrias, 1966, Fedorchenko and Zagorodnyuk, 1994, Mezhzherin, 1997a) have substituted the earlier tauricus Pallas, 1811 (type locality is mountains of Crimea), for A. flavicollis. Corbet (1978c:134), however, explained that flavicollis "preponderates in the very extensive ecological literature on the species. It therefore seems desirable to retain the name flavicollis, and the inadequacy of the original description of tauricus, which amounts only to ‘multo major et elegantissimi velleris’ (relative to A. sylvaticus), would seem to justify its rejection as not certainly determinable." Pavlinov and Rossolimo (1987) listed tauricus as nomen oblitum and Pavlinov et al. (1995a) treated it the same way but with a question. Kryštufek (2002a) countered by demonstrating that tauricus has been used as a senior synonym of flavicollis after 1899 (thus invalidating its status as a nomen oblitum), that flavicollis is the only Apodemus found in the Crimean Mtns (which negates Corbet’s concern), and that tauricus is potentially valid for replacing flavicollis. Zagorodnyuk (1992b:45) offered "Sylvaemus taurica (Pall.)" as a new combination. The nomenclatural issue requires resolution.