Niviventer confucianus (Milne-Edwards, 1871)

Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Muridae, Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona: Lynx Edicions, pp. 536-884 : 824

652.

Confucian White-bellied Rat

Niviventer confucianus

French: Rat de Confusius / German: Chinesische Weil 3 bauchratte / Spanish: Rata de vientre blanco de Confucio

Other common names: Chinese Niviventer, Chinese White-bellied Rat, Confucian Niviventer, Sulphur-bellied Rat

Taxonomy. Mus confucianus Milne-Edwards, 1871 ,

“Setchuan [= Szechwan, China].”

Interspecific and intraspecific taxonomy of N. confucianus is rather complex and unresolved. Morphologically, it isclosest to N. tenaster , but phylogenetic studies have not proven this relationship, nor a strong relationship to any other species or clade within the genus. N. fulvescens , N. huang , N. bukit , N. lotipes, and N. culturatus have been variously included in N. confucianus throughoutits taxonomic history. N. lotipes was placed as a subspecies of N. tenaster , then was given full species status. N. fulvescens is clearly distinct from N. confucianus based on morphology and genetic data. N. bukit and N. huang also were included in N. fulvescens but are now recognized as distinct species. N. culturatus was most recently split from N. confucianus based on morphology, which was later validated by genetic data. All these species have been placed under N. niviventer , but recent phylogenetic and morphological data have shown this to be inaccurate. Eight and ten subspecies of N. confucianus have been recognized in the past, most recently in 2003. G. G.Musser and M. D. Carleton in 2005 did not recognize any subspecies because of uncertainty over their validity. Recent phylogenetic work found five distinct clades within N. confucianus , and anotherset of specimens morphologically attributed to N. confucianus was found in Tibet that did not cluster with these clades. None of the subspecies proposed by Deng Xianyu and colleagues in 2000 ( confucianus , sacer, chihliensis, yushuensis, mentosus, naoniuensis, yajiangensis, and deqinesis, but notincluding N. lotipes and N. culturatus that were recognized as subspecies by them) matched these clades. Because of continuing uncertainty, additional research is required before subspecies can be definitively recognized.

Distribution. NE, C, E, S & SE China, N & E Myanmar, NW Thailand, N Vietnam, and perhaps N Laos.

Descriptive notes. Head-body 116-173 mm, tail 194-269 mm, ear 22-28 mm, hindfoot 31-40 mm; weight 43-124 g. The Confucian White-bellied Rat is large and quite variable, with long soft pelage and occasionally flexible spines and black guard hairs mixed throughout. Dorsum is deep chocolate brown to brighter reddish cinnamon brown and is usually shiny, being darkest near center of back and becoming lighter reddish cinnamon toward sides. Venter is creamy whitish to creamy yellowish, sometimes more yellowish around forelegs or hindlegs, and is sharply demarcated from dorsum. Some specimens have small light fulvous brown spot on chest. Tail is 125-135% of head-body length, covered in thin white or creamy hairs that become denser near tip, and distinctly bicolored, being light to medium brown above that tapers off near end to form white tip and creamy to very light brown below. Ears are dark brown; vibrissae are long. There are five digits on each foot, with fifth digit reduced with small claw. Skull is elongated and narrow and is not gaunt on rostral part, and zygomatic arches parallel sides of braincase. There are four pairs of mammae: one pectoral, one post-axillary, one abdominal, and oneinguinal. Chromosomal complement is 2n = 46, FN = 54 (Guangdong), FN = 60 (Shandong), and FN = 62 (Shaanxi).

Habitat. Variety of habitats at elevations of ¢.150—4000 m. The Confucian White-bellied Rat is found in mossy montane forests in Thailand and most forest habitats (tropical and subtropical moist montane and lowland forests and temperate forests) and cultivated land in China. It is twice as common in primary forest compared with secondary forest in China. It can withstand some habitat degradation.

Food and Feeding. The Confucian White-bellied Ratis semi-omnivorous and regularly hoards seeds. In a study in Dongling Mountains, Mentougou District, Beijing, China, Confucian White-bellied Rats selected wild apricot seeds ( Prunus armeniaca , Rosaceae ) for hoarding and consumed more Liaodong oak ( Quercus liaotungensis , Fagaceae ) acorns in the short term. Another study found that they preferred cultivated walnut seeds and Liaodong oak acorns over wild apricots and showed that softer seeds with less tannins were eaten, while harder seeds with more tannins were hoarded. Hoarding behavior may help them survive during periods of food storage. Confucian Whitebellied Rats adjust hoarding to larder food when they face competition with other rodent species and scatter when there is no orlittle competition.

Breeding. Confucian White-bellied Rats are polygamous and unselective when choosing mates. Males and females become more aggressive during reproductive periods. Breeding occurred in autumn, peaking in September—October, and reproductive success was influenced by amount of vegetative cover and human disturbance on islands in Qiandao Lake, eastern China. Near the Dongting Lake region, breeding occurred in all seasons except winter. Mean number of embryos was 3-7 (range 2-8); littersizes varied by season, being lowest in spring (3 young), highest in autumn (5 young), and intermediate in summer (4-3 young); and they also increased with female age and weight. Males with scrotal testes were most common in summer and autumn and least common in spring and winter.

Activity patterns. The Confucian White-bellied Rat is nocturnal and mostly terrestrial.

Movements, Home range and Social organization. Home ranges of male and female Confucian White-tailed Rats do not differ significantly in size.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Confucian White-bellied Rat has a wide distribution and presumably large overall population that does not seem to be declining because it is fairly common throughoutits distribution. It is found in many nature reserves and protected areas (e.g. Doi Inthanon National Park in Thailand and Xishuangbanna and Jiuzhaigou national nature reserves in China). It is the most well-studied species of Niviventer , although it is in need of a taxonomic revision.

Bibliography. Balakirev & Rozhnov (2010), Balakirev et al. (2011), Bao Yixin et al. (2000), Deng Xianyu et al. (2000), Dong Wenge et al. (2009), He Kai & Jiang Xuelong (2015), Jiang Qinglan (1995), Jing Meidong et al. (2007), LiYuchun et al. (2008), Lu Jigi & Zhang Zhibin (2004, 2008), Lu Liang et al. (2015), Lunde & Smith (2016), Musser (1981a), Musser & Carleton (2005), Shen Liangliang et al. (2011), Smith & Yan Xie (2008), Sun Boet al. (2009), Wang Jinxing, Zhao Xiaofan, Koh Hungsun et al. (2003), Wang Jinxing, Zhao Xiaofan, Qi Hongying & Wang Yuzhi (1997), Wang Yingxiang (2003), Wu Delin etal. (1996), Zhang Hongmao & Wang Wei (2009), Zhang Hongmao et al. (2015), Zhang Meiwen et al. (2006), Zhang Yifeng et al. (2013), Zhang Ziyu & Zhao Mingshan (1984), Zhou Yan et al. (2009).

Figures

Distribution. NE, C, E, S & SE China, N & E Myanmar, NW Thailand, N Vietnam, and perhaps N Laos.