Hylomyscus alleni (Waterhouse 1837)

[Hylomyscus] alleni (Waterhouse 1837), Proc. Zool. Soc. Lond., 1837: 77.

Type Locality: Equatorial Guinea, Bioko, Gulf of Guinea.

Vernacular Names: Allen's Hylomyscus.

Synonyms: Hylomyscus canus Sanderson 1940; Hylomyscus montis Eisentraut 1969; Hylomyscus simus G. M. Allen and Coolidge 1930.

Distribution: Equatorial Guinea (including Bioko) and West Africa from Guinea (Mt Nimba) to Gabon and Cameroon; limits unknown.

Conservation: IUCN – Lower Risk (lc).

Discussion: We do not follow Rosevear (1969) in restricting H. alleni to Bioko (= Fernando Poo), and agree with Eisentraut (1969 b) and Robbins et al. (1980) in recognizing the species in West Africa (based on our study of Eisentraut's material and other specimens). Robbins et al. (1980) reported sympatry between alleni and stella in S Cameroon, as well as cranial and chromosomal distinctions. However, the morphological differences they noted are slight and variable even within a single sample, the karyotypes all have 2n = 46 and only differ slightly in FN (68 versus 70), and they did not demonstrate whether the contrasts represented intra- or interpopulational variation. The chromosomal differences are not impressive considering that a sample referred to H. stella from Burundi had 2n = 48 and FN= 86 (Maddalena et al., 1989). Some authors (Brosset et al., 1965; Heim de Balsac and Aellen, 1965) have regarded simus as the species distributed throughout West Africa and into Angola, and stella in C Africa, but we follow Rosevear (1969) in not being able to distinguish any sample that can be called simus. The definitions of both alleni and stella on continental Africa need clarification, as Rosevear (1969) so cogently elaborated. Populations in Ghana and Sierra Leone reviewed by Grubb et al. (1998). Morphometric and ecological data recorded by Ryan and Attuquayefio (2000) and ecological data discussed by Decher and Bahian (1999) for samples from the Accra Plains in S Ghana. Information covering vertical distribution in S Côte d’Ivoire (under H. simus) recorded by Adam (1977). Discussed by Eisentraut (1973) in the context of a retrospective on faunal evolution in West Africa.