54.

Tonkin Greater Bamboo Bat

Tylonycteris tonkinensis

French: Vespertilion du Tonkin / German: Tonkin-Bambusfledermaus / Spanish: Tilonicterio de Tonkin

Other common names: Tonkin Bamboo Bat

Taxonomy. Tylonycteris tonkinensis Tu et al, 2017,

“ VIETNAM: Copia Nature Reserve, Co Ma commune, Thuan Chau District, Sen La Province, 21°21.797' N, 103°30.562' E, 1286 m 4.5.1.”

Only recently described, but south-eastern China populations now attributed to this species were previously regarded as 7. robustula . Exact distributional limit between this species and 7. malayana is currently uncertain. Monotypic.

Distribution. SE China (Sichuan, Yunnan, Guizhou, Guangxi, and Hainan), N Vietnam, and NE Laos; it may extend into Myanmar, based on proximity of Chinese specimens to Myanmar border.

Descriptive notes. Head-body 35-7-45 mm, tail 19-3-34 mm, ear 7-10-2 mm, hindfoot 4-3-6-6 mm, forearm 24-3-29 mm; weight 4-1-6-6 g. Head is dorso-ventrally flattened and broadened. Pelage is variable but generally more or less golden brown with a red tinge dorsally (hairs golden red basally, with dark brown tips), and slightly lighter golden brown ventrally. Membranes are dark brown Ears are subtriangular, relatively long with a broadly rounded tip; tragus is short and blunt. Base of thumbs and soles of hindfeet have well-developed rounded fleshy pads for gripping smooth surfaces. Wing membrane attaches at base of metatarsus; uropatagium extends to tip of tail, and calcar is over halfway to tail from ankle. Skull is small, lightly built, and very flat; rostrum is short; there is no sagittal crest; lambdoid crests are well developed. I? is bicuspid with small cusps on the cingulum; P* is unicuspid and about halfthe size of the crown area of I?; C! has posterior supplementary cusps; there is a conspicuous diastema between C' and I’; three lower incisors are tricuspid; P, and P, are subequal to each other in height and crown area. Chromosomal complement has 2n = 32 and FN = 50 (Yunnan, China); and 2n = 32 and FN = 52 (Guangxi, China).

Habitat. Associated with woody bamboo groves and has been captured near bamboo groves in forest edge next to rural-residential areas. Tonkin Greater Bamboo Bats have been recorded at elevations of 1010-1286 m in Vietnam and lower in Laos, at 500-800 m.

Food and Feeding. The Tonkin Greater Bamboo Bat is insectivorous, and feeds on a variety offlying prey;it forages by aerial-hawking and is a slow flier (4-3 m/s in straight flight). It avoids areas cluttered with vegetation and eats prey on the wing after catching it directly in the mouth. In Guangxi, stomach samples included Hymenoptera (62:3% by volume), Diptera (29-6%), Coleoptera (6%), Hemiptera (1-5%), and very small amounts of Orthoptera, Trichoptera, and Ephemeroptera . This species generally ate smaller food than the sympatric Indomalayan Lesser Bamboo Bat (7. fulvida).

Breeding. Births of twins have been recorded at end of May, and young seemed to be volant near end ofJune in Guangxi.

Activity patterns. Tonkin Greater Bamboo Bats roost inside hollow bamboo internodes. Call shape is FM sweep with average minimum frequency of 47-2 kHz, maximum frequency 100-1 kHz, and call duration 3-9 milliseconds in Guangxi. Another study from Longzhou County, Guangxi, recorded peak frequency of 57-7 kHz.

Movements, Home range and Social organization. Roost size in Guangxiis 1-13 bats in total, with males roosting solitarily more often than females. About 40-6% of roosts include both males and females, and another 40-6% were solitary males. Groups of 1-2 Tonkin Greater Bamboo Bats were most common (making up 59-4% of roosts). Roosts were frequently changed and, although this species did not share roosts with Indomalayan Lesser Bamboo Bats, both species took up the same roosts at different times.

Status and Conservation. Not assessed on The IUCN Red List. The Tonkin Greater Bamboo Bat was only recently described and seems to have a relatively small distribution compared to its relatives, but may be common throughout its range. More research is needed.

Bibliography. Ao, Lei et al. (2006), Feng Qing (2008), Huang Chujing et al. (2014), Smith & Xie Yan (2008), Tu Vuong Tan, Csorba et al. (2017), Yu Wenhua et al. (2008), Zhang Libiao, Jones, Parsons et al. (2005), Zhang Libiao, Jones, Rossiter et al. (2005), Zhang Libiao, Liang Bing, Parsons et al. (2007), Zhang Libiao, Liang Bing, Zhou Shanyi et al. (2004a, 2004b), Zhang Libiao, Zhu Guangjian et al. (2008).