758.

Annandale’s Sundaic Rat

Sundamys annandalei

French: Sundamys d’Annandale / German: Annandale-Sunda-Riesenratte / Spanish: Rata de Sonda de Annandale

Other common names: Annandale’s Rat

Taxonomy. Mus annandalee Bonhote, 1903,

Sungkei, South Perak, Malaysia (Malay Peninsula) .

S. annandale: was originally classified as a species of Rattus, although recent phylo- genetic studies have shown the species to be a member of Sundamys . S. annandalei is the sister species to S. infraluteus . Monotypic.

Distribution. E Sumatra and adjacent Is (Rupat and Padang), Peninsular Malaysia,

and Singapore.

Descriptive notes. Head—body 173-220 mm, tail 225-263 mm, ear 20-23 mm, hindfoot 37-41 mm; weight 155-261 g. Annandale’s Sundaic Ratis smaller than other species of Sundamys . Dorsum is grayish brown; venteris white to pale yellow, grayish white, or buff white. Fur is shaggy and soft, with some longer guard hairs on rump. Tail is longer (100-150%) than head-body length in all species of Sundamys, and foot length is shortest on Annandale’s Sundaic Rat (37-41 mm). Zygomatic plate of zygomatic arch is placed anterior to M'; squamosal root of zygomatic arch is near tympanic bullae. In palatal and lateral view, large and inflated tympanic bullae distinguish Annandale’s Sundaic Rat from other species of Sundamys . Sphenopterygoid vacuity is present. Com- pared to skull length, molars are small. There are four pairs of mammae: one pectoral, one post-axillary, and two inguinal. Annandale’s Sundaic Rat and its Sundamys relatives share the following characteristics: medium to large body size compared with other Rattini from the Sundaic region;slightly inflated rostrum without marked constriction anterior to lacrymal notch; short incisive foramina relative to condylobasal length and usually not reaching anterior margin of M'; small sphenopalatine vacuity; upper mo- lars anchored by five (M'), four (M?), or three roots (M?); lower molars anchored by four (m,) or three roots (m,, m,); palatal bridge extending only slightly beyond molar rows without forming wide and deep shelf; wide mesopterygoid fossa connecting with sphenopalatine vacuity; posterior cingulum often present on M'; usually large and well-developed cusp t3 on M* and M?; wide lamina on lower molars made of similar size cuspids that do not form lamina with arcuate or acute angles; fused antero-labial and antero-lingual cusps of m forming large lamina; and anteroand postero-labial cusplets on m, always present and well-developed.

Habitat. Altered habitats such as perturbed primary forests, secondary forests, and plantations (e.g. rubber). Annandale’s Sundaic Rat is associated with wet habitats, such as streams and riverbanks, and is a lowland lineage. In Perak in peninsular Malay- sia, it was apparently uncommon, and some authors suggested that it was localized and confined to secondary habitats. In Selangor, it was surprisingly common in lowland secondary forests and plantations; none was taken in deep forest.

Food and Feeding. Annandale’s Sundaic Rat is probably omnivorous.

Breeding. No information.

Activity patterns. Annandale’s Sundaic Rat is nocturnal. It has a scansorial or arboreal lifestyle compared with its close relative, Muller’s Rat ( S. muelleri). Arboreal habits of Annandale’s Sundaic Rat couldbe related to lower dispersal abilities and its more restricted distribution.

Movements, Home range and Social organization. It is unknown under what ecologi- cal conditions Annandale’s Sundaic Rat might have originated and whyit has such a restricted distribution given that there are no apparent ecological barriers that could limit its expansion across Sumatra and Peninsular Malaysia.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as Rattus annandaler). Annandale’s Sundaic Rat has a relatively small distribution but is found in numerous protected areas. In lowland habitats, it may be threatened by habitat de- struction from agricultural expansion and logging, although the species seems to do well in some secondary and disturbed habitats such as plantations.

Bibliography. Aplin (20162), Bonhote (1903a), Camacho-Sanchez et al. (2017), Chasen (1940), Harrison (1954a, 1954b), Harrison & Lim (1950), Kloss (1908), Lim (1966, 1970), Lyon (1908), Medway (1969), Musser & Carleton (2005), Muul & Lim (1971).