Apomys gracilirostris Ruedas 1995

Apomys gracilirostris Ruedas 1995, Proc. Biol. Soc. Wash., 108: 305.

Type Locality: Philippines, Mindoro Isl, Mindoro Occidental Province, Municipality of San Teodoro, North Ridge approach to Mt Halcon, 1580 m, 13°16'48"N, 121°59'19"E.

Vernacular Names: Large Mindoro Apomys.

Distribution: Greater Mindoro Faunal Region. A Mindoro endemic recorded only from montane forest on northern flank of Mt Halcon between 1250 and 1950 m, but may occur throughout the Mindoran highlands still covered by mountain forest (Ruedas, 1995).

Conservation: IUCN – Vulnerable.

Discussion: Apomys datae Group. In morphology of rostrum and incisors, A. gracilirostris is unique among species of Apomys, but phylogenetic analysis of mtDNA cytochrome b sequences placed it with the Luzon A. datae (Steppan et al., 2003) . Large body size, long rostrum relative to rest of cranium, and primitive pattern of cephalic arterial supply also tie A. gracilirostris to A. datae (Ruedas, 1995; Musser’s study of the Mindoran specimens). Presence of A. gracilirostris on Mindanao likely reflects dispersal to that island, probably from an ancestral stock on Luzon (Steppan et al., 2003). Discovery of A. gracilirostris accentuates the dual biogeographic nature of Mindoro’s murine fauna: Chrotomys mindorensis, Apomys musculus, A. gracilirostris, and Rattus everetti have Philippine affinities; Rattus mindorensis, an undescribed species of Maxomys (specimens examined by Musser), and Anonymomys mindorensis are related to Indochinese and Sundaic faunas.