739.

Indomalayan Spiny Rat

Maxomys surifer

French: Maxomys roux / German: Rote Rajah-Ratte / Spanish: Rata espinosa de Indomalasia

Other common names: Indomalayan Maxomys, Red Spiny Rat, Red Maxomys, Red Spiny Maxomys

Taxonomy. Mus surifer G. S. Miller, 1900,

“mounatin of Trong, Lower Siam [= Peninsular Thailand], at an altitude of about 3,000 feet [=914 m].”

Maxomys is sister to all other Rattini ex- cept Crunomys, which is nested within Maxomys phylogenetically, making the genus paraphyletic. Maxomys surifer is sister to M. bartelsii, and this clade is sister to all other Maxomys except M. moi . Maxomys surifer almost certainly represents a species complex, with considerable genetic and morphological variation throughout its distribution. It has been included as a synonym of M. rajah in the past, but morphological and genetic data support its recognition as a distinct species. Seven subspecies recognized.

Subspecies and Distribution.

M.s.suriferG.S.Miller,1900—SThailandandPeninsularMalaysia,aswellasmanyoffshoreIs.

M.s.carimataeG.S.Miller,1906—BorneoaswellasmanyoffshoreIs(includingNatunaI).

M.s.finusKloss,1916—EThailand,SLaos,C&SVietnam,Cambodia,andmanyoffshoreIs.

M.s.ravusH.C.Robinson&Kloss,1916—Sumatra,Java,andmanyoffshoreIs.

M.s.siarmaKloss,1919—N&WThailandandSMyanmar.

M.s.tonkinensisBalakirev,2017—NVietnamandNLaos;probablyextremeSChina(Yunnan).

M. s. ubecus Lyon, 1911 — E Borneo.

Descriptive notes. Head—body 155-226 mm, tail 146-227 mm, ear 20-28 mm, hindfoot 32-47 mm; weight 90-285 g. The Indomalayan Spiny Rat is a large species of Maxomys . Sundaic populations are generally smaller than mainland South-east Asian populations. Pelage is short and very spiny, with dark stiff spines dorsally, soft white spines ventrally, and black guard hairs. Dorsum varies from orangish to reddish brown, being lighter on sides and distinctly darker along back. Dorsal pelage also extends to around ankles unlike on Rajah Sundaic Spiny Rat ( M. rajah). Venteris white, usually with reddish brown or orangishbrown collar around lower neck that ends in line leading up neck, although this can be partially or fully visible. Juveniles are very dark blackish brown, fading through gray to white ventrally, and they are not identifiable to the species level within the genus. Feet are white, long, and narrow. Ears are long and brown;vibrissae are long and dark. Tail is 95-100% of head-body length and distinctly bicolored, dark brownish black dorsally and white ventrally. Skull has relatively short and wide incisive foramina. Various species of mites (Laelaps), ticks (Ixodes), fleas (Xenopsylla), pseudoscorpion (Chelifer cancroides), and blood parasites (Microfilaria, Trypanosoma, Anaplasma, and Grahamella) have been recorded from the Indomalayan Spiny Rat. There are four pairs of mammae: one pectoral, one post-axillary, and two inguinal. Chromosomal complement is 2n = 52, FN = 66.

Habitat. [Lowland primary forest, forest edge, and gardens from sea level to elevations of 1680 m. Indomalayan Spiny Rats can be found in secondary or disturbed habitats, although this is less common.

Food and Feeding. The Indomalayan Spiny Rat eats roots, fruit, seeds, insects, and small vertebrates. It scatter-hoards nuts in Malaysia.

Breeding. Litters have 2-5 young (average 4-8 in southern Vietnam).

Activity patterns. This Indomalayan Spiny Rat is nocturnal and terrestrial. It builds nests in burrows (c¢.2 m deep ending in nesting chamber) and rarely in cavities in logs or roots, with 1-2 entrances covered with leaf litter.

Movements, Home range and Social organization. Populations fluctuate between wet and dry seasons, increasing in abundance at beginning of wet season, leveling off through wet season, and peaking just after wet season in southern Vietnam. Indomalayan Spiny Rats are sensitive to flooding and extreme weather such as droughts, which can decrease abundance. In central Thailand, home range, biomass, and density were highest in rainy seasons.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Indomalayan Spiny Rat has a very extensive distribution—widest for the genus—and occurs in many protected areas. It faces no major threats and is considered common throughout its distribution.

Bibliography. Achmadi et al. (2013), Aplin (2016v), Balakirev et al. (2017), Corbet & Hill (1992), Francis (2008), Gorog et al. (2004), Kuznetsov & Filatova (2007), Musser & Carleton (2005), Musser et al. (1979), Nor (2001), Phillipps & Phillipps (2016), Rickart & Musser (1993), Smith & Yan Xie (2008), Steppan & Schenk (2017), Thanee et al. (2009), Walker & Rabinowitz (1992), Wells, Lakim & Pfeiffer (2006), Wells, Pfeiffer et al. (2004), Wu Delin et al. (1996), Yong (1972).