Mastomys erythroleucus (Temminck 1853)

[Mus] erythroleucus Temminck 1853, Esquisses Zool. sur la Cote de Guine: 160.

Type Locality: Guinea.

Vernacular Names: Reddish-white Mastomys.

Synonyms: Mastomys calopus (Cabrera 1906); Mastomys gambianus (Thomas 1911); Mastomys peregrinus (De Winton 1898).

Distribution: Mostly Subsaharan N Africa; an isolated population in WC Morocco (Aulagnier, 1991; Aulagnier and Thevenot, 1986); main range in Gambia, Senegal, Guinea, Ghana, Sierra Leone, Côte d’Ivoire, Burkina Faso, Mali, Niger, Benin, Nigeria, Cameroon, Central African Republic, Sudan, Ethiopia, E. Dem. Rep. Congo, Burundi, and W Uganda. See Granjon et al. (1997 b), Volobouev et al. (2001), and Ziegler et al. (2002).

Conservation: IUCN – Lower Risk (lc).

Discussion: Chromosomal (2n = 38, FNa = 50-56) and electrophoretic data as well as fur color (reddish brown dorsum, whitish venter) set this species apart from other Mastomys with which it occurs (Baskevich and Orlov, 1993; Duplantier et al. 1990 a, b; Granjon et al., 1997 b; Lavrenchenko et al., 1992; Volobouev et al., 2001; and references cited therein). The geographic range described by Granjon et al. (1997 b) is primarily derived from the distribution of samples with 2n = 38 (see references to chromosomal reports cited by Granjon et al., 1997 b). Codjia et al. (1996) documented chromosomal distinctions between M. erythroleucus and M. natalensis from S Benin. Mastomys erythroleucus is sympatric with M. huberti and M. natalensis in Senegal (Duplantier et al., 1990 a, 1996). Reproductive distinctions among M. erythroleucus, M. natalensis, and M. huberti in Senegal documented by Duplantier et al. (1996). In Senegal, M. erythroleucus is a generalist and inhabits a variety of habitats, but M. huberti is restricted to humid natural or cultivated areas, and M. natalensis is found only in villages (Duplantier et al., 1996). Ethiopian populations of M. natalaensis and M. erythroleucus exhibited similar ecological ranges (Bulatova et al., 2002). Phylogenetic analysis of chromosomal data indicates that M. erythroleucus, although still a member of Mastomys and not Myomys or Praomys, is set apart from M. natalensis, M. huberti, and M. coucha, the other species analyzed (Britton-Davidian et al., 1995). Mitochondrial DNA cytochrome b sequences identifies M. erythroleucus as sister group to M. natalensis (Lecompte et al., 2002 b). Granjon et al. (1997 b) provided an excellent review of M. erythroleucus and noted that while no single body or cranial measurement will unambiguously discriminate among M. erythroleucus, M. natalensis, and M. huberti in Senegal, discriminant function analyses of cranial, mandibular, and dental measurements do separate the three species. Lavrenchenko and Baskevich (1996) documented differences in spermatozoal morphology distinguishing Ethiopian M. erythroleucus and M. natalensis, and Bulatova et al. (2002) recorded chromosomal contrasts; the two species are sympatric in the Gambela region. Reviews covering taxonomy, distribution, ecology, and other subjects are available for Morocco (Aulagnier, 1991; Aulagnier and Thevenot, 1986); Gambia, Ghana, and Sierra Leone (Grubb et al., 1998); S Ghana (Ryan and Attuquayefio, 2000) and Accra Plains of S Ghana (Decher and Bahian, 1999).

More than one species is likely represented in what is now called M. erythroleucus. In an analysis of R- and C-bands of samples with 2n = 38, Volobouev et al. (2001) reported that the FN varied from 40 to 60, a result of pericentric inversion polymorphism involving 3-12 chromosome pairs. Presuming that introgressive hybridization is interrupted among populations differing from one another by 3-5 to 11-12 pericentric inversions, Volobouev et al. hypothesized the presence of three "cryptic" species. One (designated MER-1 with FN = 50-56) occurs throughout Subsaharan Africa and includes karyotyped samples from Senegal, Côte d’Ivoire, Mali, Benin, Cameroon, Dem. Rep. Congo, Sudan, and most likely Ethiopia and the isolated Moroccan population; this is M. erythroleucus. The second species (MER-2 with FN = 40-41) is represented by samples from Chad and Sudan (see account of M. kollmannspergeri), and the third "tentative species" (MER-3 with FN = 59-60) consists of samples from E Dem. Rep. Congo, W Uganda, and possibly Mali and Chad. Volobouev and his colleagues are currently testing this hypothesis by analyses of molecular traits, and have also identified a new 2n = 38 chromosomal species from Niger (MER-4, FN = 52).

The taxa calopus and peregrinus are based upon Moroccan specimens and Aulagnier and Thevenot (1986) allocated them to the synonymy of M. erythroleucus, the only species of Mastomys recorded from that country. Wroughton (1908 b) claimed gambianus was a synonym of erythroleucus and Grubb et al. (1998) treated it as such. At the present time we cannot allocate the following names identifying holotypes collected from within what is now accepted as the range of M. erythroleucus and M. natalensis. Sudan: agurensis Setzer, 1956; azrek (Wroughton, 1911); blainei (Wroughton, 1907); kulmei Setzer, 1956; limbatus (Wagner, 1845); macrolepis (Sundevall, 1843); marrensis Setzer, 1956. Holotypes of azrek, blainei, and macrolepis from S Sudan may be examples of M. kollmanspergeri (Denys et al., 2002; see that account). Ethiopia: gardulensis (Frick, 1914; a species of Praomys according to Yalden et al., 1975, 1996, but holotype clusters with those of other Mastomys in the morphometric analysis of Van der Straeten and Robbins, 1997); lateralis (Heuglin, 1877); tacaziena (Heuglin, 1877). The taxon fuscirostris Wagner, 1845 (type locality, Sennaar, Sudan) was associated with Myomys albipes by G. M. Allen (1939) and recognized as Praomys albipes fuscirostris by Setzer (1956). The holotype has never been examined or identified. It cannot be an example of albipes, which is an Ethiopian endemic that has never been collected outside of that country, and we suspect the name should be associated as a species or synonym with Mastomys and provisionally list it here until the holotype can be located and identified.