675.

Little Indochinese Field Rat

Rattus sakeratensis

French: Rat de Sakaerat / German: Hainan-Reisfeldratte / Spanish: Rata de campo de Indochina pequena

Taxonomy. Rattus sakeratensis Gyldenstolpe, 1917,

“Sakerat, Eastern Siam [= Thailand].”

Rattus sakeratensis was recently recognized as a distinct species from R. losea because it is genetically sister to Lineage IV of R. tanezumi, with R. tiomanicus sister to them both. These two species are sister to a clade containing R. rattus and R. tanezumi, being Lineage V in the R. rattus clade within the R. rattus species group (see the R. rattus

and R. tanezumi). Holotype of this species

is a “chimera,” with its skin but a skull of a species of Maxomys . Rattus sakeratensis needs more research to fully understand its taxonomic position and its full distribution. Species identity ( R. sakeratensis or R. losea) of populations other than in northen or central Thailand and north-western Laos is uncertain. Monotypic.

Distribution. N &C Thailand and Vientiane plain of N Laos; outside these areas range limits unknown.

Descriptive notes. Head-body 154-6 mm, tail 133-2 mm, ear 28-1 mm, hindfoot 17-2 mm; weight 83-6 g (averages). The Little Indochinese Field Rat is small and very similar to the Losea Rat ( R. losea) but significantly smaller and more richly colored, with shortertail that is dark above and below and darker feet. Dorsum is brown to reddish brown, mixed with black guard hairs. Venter is dark gray, with buff-tipped hairs and not sharply demarcated from dorsum. Feet are light brown above, with white sides and digits. Ears are brown; vibrissae are long. Tail is ¢.86% of head-body length and unicolored blackish brown, with short hairs covering it. Thirteen different species of gastrointestinal helminth have been recorded from the Little Indochinese Field Rat. There are five pairs of mammae: two axillary and three inguinal.

Habitat. Rain-fed native fields and apparently cultivated fields.

Food and Feeding. The Little Indochinese Field Rat is likely omnivorous.

Breeding. No information.

Activity patterns. The Little Indochinese Field Rat is nocturnal.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The IUCN Red List. The Little Indochinese Field Rat was only recently recognized as distinct from the Losea Rat, which is listed as Least Concern. The Little Indochinese Field Rat seems to be fairly common but has a much more limited distribution than related speciesand may be at risk of habitat degradation because it is not generally associated with humans.

Bibliography. Aplin etal. (2011), Blasdell et al. (2015), Chaval (2014), Gyldenstolpe (1917), Latinne, Waengsothorn et al. (2013), Morand et al. (2015), Musser & Carleton (2005), Pages et al. (2013).