Chrotomys silaceus Thomas 1895

Chrotomys silaceus Thomas 1895, Ann. Mag. Nat. Hist., ser. 6, 16: 161.

Type Locality: Philippines, N Luzon Isl, Mt Data, Lepanto, 8000 ft (2440 m).

Vernacular Names: Blazed Luzon Chrotomys.

Distribution: Greater Luzon Faunal Region in the Philippines. Endemic to montane forest in N Luzon; known from Benguet and Kalinga provinces (Heaney et al., 1998; Largen, 1985; Rickart and Heaney, 2002; Sanborn, 1952 a), 1800-2500 m, but probably lives in montane forest formations elsewhere on N Luzon.

Conservation: IUCN – Lower Risk (lc) as Celaenomys silaceus .

Discussion: Standard karyotype (2n = 44, FN = 52) is indistinguishable from those of Rhynchomys isarogensis and Chrotomys gonzalesi (Rickart and Heaney, 2002) . Made the type species of Celaenomys, a genus separated from Chrotomys by its lack of M3 (Thomas, 1898 b). Celaenomys has been recognized in past compendia (Ellerman, 1941; Heaney et al., 1998; Musser and Heaney, 1992), but recently synonymized with Chrotomys because M3 occurs in one or both molar rows in some specimens (Corbet and Hill, 1992; Musser’s observations). A suite of highly distinctive and derived external and cranial traits unites silaceus with other species of Chrotomys to the exclusion of the other Philippine shrew rats, Archboldomys, Crunomys, and Rhynchomys (Musser and Heaney, 1992) .