Apomys datae (Meyer 1899)

[Apomys] datae (Meyer 1899), Abh. Mus . Dresden, ser. 7, 7: 25.

Type Locality: Philippines, N Luzon Isl, Lepanto.

Vernacular Names: Northern Luzon Apomys.

Synonyms: Apomys major Miller 1910 .

Distribution: Greater Luzon Faunal Region. Most records come from highlands in N Luzon where it inhabits primary montane forest in the Sierra Madre and Central Cordillera, 760-2500 m (Heaney et al., 1998; Musser, 1982 b), but the species has also been taken near sea level on W coast of Ilocos Norte Province (AMNH 252474, 252475).

Conservation: IUCN – Lower Risk (lc).

Discussion: Member of the Apomys datae Group according to Musser (1982 b), who also documented the inclusion of major; the Mindoran A. gracilirostris is the only other member of the A. datae group (see account below). Standard karyotype (2n = 44, FN = 54) closely similar to A. musculus and the shrew rats Chrotomys (including Celaenomys) and Rhynchomys and strikingly different from other species of Apomys sampled (Rickart and Heaney, 2002). The karyotype of A. datae, along with a primitive pattern of cephalic arterial circulation, suggest it is the most primitive species within Apomys . It, along with A. gracilirostris, also form the basal clade within the genus as revealed by phylogenetic analysis of mtDNA cytochrome b sequences (Steppan et al., 2003).