Sundamys muelleri (Jentink 1879)

[Mus] muelleri Jentink 1879, Notes Leyden Mus ., 2: 16.

Type Locality: Indonesia, W Sumatra, Batang Singgalang, Padang Highlands.

Vernacular Names: Muller's Sundamys.

Synonyms: Sundamys balabagensis (Sanborn 1952); Sundamys balmasus (Lyon 1916); Sundamys borneanus (Miller 1913); Sundamys campus (Robinson and Kloss 1916); Sundamys chombolis (Lyon 1909); Sundamys crassus (Lyon 1911); Sundamys credulus (Chasen 1940); Sundamys culionensis (Sanborn 1952); Sundamys domitor (Miller 1903); Sundamys firmus (Miller 1902); Sundamys foederis (Robinson and Kloss 1911); Sundamys integer (Miller 1901); Sundamys otiosus (Chasen 1935); Sundamys pinatus (Lyon 1916); Sundamys pollens (Miller 1913); Sundamys potens (Miller 1913); Sundamys sebucus (Lyon 1911); Sundamys terempa (Chasen and Kloss 1928); Sundamys valens (Miller 1913); Sundamys validus (Miller 1900); Sundamys victor (Miller 1913); Sundamys virtus (Lyon 1916); Sundamys waringensis (Sody 1941) .

Distribution: Endemic to large and small islands and penninsula on the Sunda Shelf south of the Isthmus of Kra (10E30' N): SW peninsular Burma, peninsular Thailand, Malay Peninsula, Sumatra, Borneo, and Palawan; and on the smaller islands of Siantan (Anamba Isl), many of the Riau Isls, Tuangku and Bangkuru (Banjak Isls), Mansalar (W Sumatra), Pinie, Tanahmasa and Tanahbala (Batu Isls), Banka, Bunguan and Serasan (Natuna Isls), Karimata Isl (SW Borneo), Sebuku (SE Borneo), Balembangan and Banggi (N Borneo), and Balabac, Culion, and Busuanga (Palawan Faunal Region). Older published records from islands off Sunda Shelf (Nicobars, for example) proved to represent other species (all but the Karimata records are documented in the gazetteer and range maps in Musser and Newcomb, 1983; specimens in UMMZ and MZB were obtained on Karimata Isl by A. J. Gorog in 2000). Does not occur on Java.

Conservation: IUCN – Lower Risk (lc).

Discussion: Morphological, chromosomal, and spermatozoal data suggested S. muelleri is a distant relative of Rattus but in the same monophyletic clade (Breed and Yong, 1986; Musser and Newcomb, 1983; Watts and Baverstock, 1994 b). Like Maxomys surifer, which also has an extensive insular distribution on the Sunda Shelf (see that account), nearly every island sample of S. muelleri was described as a separate subspecies, some based on real differences in pelage coloration and body size, others diagnosed primarily by their insular distribution (see history in Musser and Newcomb, 1983). There are detectable differences among some samples. Populations from SW Burma, Peninsular Thailand, and the Malay Peninsula, for example, are significantly larger in body size than those from elsewhere on the Sunda Shelf and may be a separate species (Musser and Newcomb, 1983). Phylogenetic analyses of gene sequences from insular and peninsular samples of S. muelleri may illuminate significance and historical origin of the documented morphological variation.

Occurrence of S. muelleri on peninsular Mt Santubong in W Sarawak recorded by Tuen et al. (2000), and its distribution and ecology on the small islands off the tip of N Sabah documented by Md Nor (1996). Generally a lowland species, S. muelleri reaches 1650 m on slopes of Mt Kinabalu in Sabah (Md Nor, 2001, and citations therein).