799.

Luzon Broad-toothed Rat

Abditomys latidens

French: Rat 4 dents larges / German: Luzon-Breitzahnratte / Spanish: Rata de dientes anchos de Luzon

Taxonomy. Rattus latidens Sanborn, 1952,

“Mount Data, altdtude 7,500 feet [= 2286 m|, Mountain Province, Luzon Island, Philippine Island.”

This species is monotypic.

Distribution. Known only from two localities on N & C Luzon I, Philippines.

Descriptive notes. Head-body 271- 232 mm, tail 216-242 mm, ear 24 mm, hindfoot 45-47 mm; weight 269 g. The Luzon Broad-toothed Rat is large, with long unicolored tail. Forefeet have large nail instead of claw on each hallux. Dorsal parts of head—body are brown, with tawny hues. Ventral parts are buff yellowish, with gray underfur. There are four pairs of mammae: one pectoral, one post-axillary, and two inguinal. Squamosal roots of zygomatic arches are laterally inserted high on braincase side; there is no alisphenoid strut bone covering lateral part of alisphenoid canal; masticatory-buccinator foramina are fused with foramen ovale accessorius; tympanic bullae are inflated and large; incisive foramina are long and narrow; interparietal is squarish, anterior one-third is between parietals, and posterior two-thirds tops occipital bulge; short palatal bridge ends well before M?; pterygoid and mesopterygoid fossa are well-developed; sphenopterygoid and sphenopalatine vacuities are large and wide; upperincisors are wide; cheek teeth are wide and long, with high cusps that typically slant and overlap posteriorly; cusps are strongly interlocked; upper molars are anchored by five (M"), four (M?), or three roots (M?); lower molars are anchored by four (m,) or three roots (m,, m,); M* has squarish occlusal outline, only slightly smaller than M?; no cusps t7 occur on upper molars; no posterior cingula and nocusps occur on t3 of M?and M?; cusp t9 is fused with cusp t8 on M' and M?; lower molar occlusal surfaces are made of transverse laminae; small antero-labial cusps occur on m,and m; wide and conic posterior cingulum is situated at center of posterior margin of m and m,; antero-central cusp is absent on m; and lower molars do not have labial cusplets.

Habitat. Primary and secondary habitats, including near a ricefield station.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. The Luzon Broad-toothed Rat is probably nocturnal and arboreal.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. The Luzon Broad-toothed Rat was collected on Mount Data, in a place where there is no more primary forest. It was also collected near the International Rice Research Centre. Despite intensive field survey in Luzon (Balbalasang-Balbalan National Park, Sierra Madre Range, Mount Amuyao), it has not been collected there for more than forty years.

Bibliography. Balete et al. (2011), Heaney, Balete & Rickart (2016), Musser (1982b), Musser & Heaney (1992), Rickart, Balete, Alviola et al. (2016), Rickart, Balete, Rowe & Heaney (2011), Sanborn (1952a).