751.

Whitehead’s Sundaic Spiny Rat

Maxomys whiteheadi

French: Maxomys de Whitehead / German: \Whitehead-Rajah-Ratte / Spanish: Rata espinosa de Sonda de Whitehead

Other common names: \Whitehead's Spiny Rat, Whitehead's Sundaic Maxomys

Taxonomy. Mus whiteheadi Thomas, 1894,

“[Mount] Kina Balu,” northern Borneo, Malaysia.

Maxomys whiteheadi forms a clade with M. hylomyoides and M. musschenbroekii and previously included specimens now allocated to recently described M. tajuddinit. Recent genetic studies showed significant genetic variation, perhaps reflecting multiple subspecies or even species within M. whiteheadi and requiring additional investigation. Monotypic.

Distribution. S peninsular Thailand, Peninsular Malaysia, Sumatra, Borneo, and some offshore Is.

Descriptive notes. Head—body 100-126 mm,tail 88-108 mm, ear 15-18 mm, hindfoot 22-30 mm; weight 35-80 g. Whitehead’s Sundaic Spiny Rat is small, with short and spiny pelage. Dorsum is dark rufous brown or very dark brown, lighter on sides and darker on back, with gray underfur and extensive stiff spines throughout. Venteris gray to orangish gray, with gray underfur and orange buff tips, softer spines, and not sharply demarcated from dorsum. Each eye has dark ring. Ears are relatively long and brownish gray; vibrissae are long and dark. Feet are white, long, and narrow. Tail is 85— 90% of head-body length and bicolored, dark brownish black above and white below. Skull has small bullae and short palatal foramen. Various nematodes (Nippostrongylus smalesae, Heligmonoides bulbosus, and Syphacia maxomyos) and fleas (Laelaps sanguisugus, L. sculpturata, and L. aingworthae) have been recorded from Whitehead’s Sundaic Spiny Rat. There are four pairs of mammae: one pectoral, one post-axillary, and two inguinal. Chromosomal complement is 2n = 36, FN = 71 (males) and 72 (females).

Habitat. Primary and secondary forests, usually lowland regions and around tall trees, at elevations up to 2100 m. Whitehead’s Sundaic Spiny Rat can be found in paddy fields surrounded by forest, mangrove forests, disturbed habitat, plantations, and oil palm habitats.

Food and Feeding. Whitehead’s Sundaic Spiny Rat eats ants, other insects, and various plant matter. Two captive individuals ate fruits of Neoscortechinia forbesii ( Euphorbiaceae); Lithocarpus gracillus ( Fagaceae); and Parashorea malaanonan and Shorea fallax and Shorea leprosula/parvifolia (all Dipterocarpaceae); they refused Dryobalanops (Dipterocarpaceae), Aglaia (Meliaceae), various Ficus (Moraceae), and Tetrastigma (Vitaceae) . Seeds of Lithocarpus were buried under leaves in the cage.

Breeding. Whitehead’s Sundaic Spiny Rat can breed monogamously, with pairs sharing part of their home ranges.

Activity patterns. Whitehead’s Sundaic Spiny Rat is nocturnal and terrestrial, building nests in burrows on the ground.

Movements, Home range and Social organization. In Borneo, home ranges were 200-1400 m? (mean 644-4 m?), and females (675 m?) had larger home ranges than males (400 m?). Home rangesrarely overlap, but when they do,it is usually between a male and a female rather than individuals of the same sex. There is significant overlap between home ranges of Whitehead’s Sundaic Spiny Rat and sympatric Rajah Sundaic Spiny Rat ( M. rajah). Populations fluctuate from very common to very rare between years, being less abundant during times of drought. Whitehead’s Sundaic Spiny Rat has been found at low densities (greater than 1 ind/ha) in paddy fields but is still more common than most other rodents. It is less abundant on island habitats than mainland habitats.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. Whitehead'’s Sundaic Spiny Rat has a wide distribution and is found in numerous protected areas, including Mount Kinabalu National Park, Gunung Stong State Park, and Wang Kelian State Park in Malaysia. In some areas,it is the most common rodent species. It is predicted to have experienced a population decrease of more than 30% in the last ten years based on rate of deforestation in its distribution.

Bibliography. Achmadi, Esselstyn et al. (2013), Achmadi, Maryanto et al. (2012), Dewi et al. (2015), Francis (2008), Gorog et al. (2004), Hasegawa et al. (2017), Jayaraj,Daud et al. (2013), Jayaraj, Tahir et al. (2012), Lynam & Billick (1999), Madinah et al. (2011), Musser & Carleton (2005), Musseret al. (1979), Nakagawa et al. (2007), Nor (2001), Paramasvaran et al. (2009), Phillipps & Phillipps (2016), Rickart & Musser (1993), Ruedas, L.A. (2016b), Steppan & Schenk (2017), Wells & Bagchi (2005), Wells, Corlett et al. (2009), Wells, Pfeiffer et al. (2004).