Myotis pilosus
Creators: name: Don E. Wilson
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Chiroptera
Vespertilionidae
Myotis
Myotis pilosus

description: 478.
Ricketts Big-footed Myotis
Myotis pilosus
French: Murin de Rickett / German: Rickett-Wasserfledermaus / Spanish: Ratonero de Rickett
Other common names: Rickett's Big-footed Bat
Taxonomy. Vespertilio (Leuconoe) pilosus Peters, 1869,
type locality not given.
Subgenus Myotis; macrodactylus species group. See M. petax. Due to confusion with the type locality (thought to be Montevideo, Uruguay, South America), most authors used the name M. ricketti proposed by O. Thomas in 1894 and ignored the original name M. pilosus, which is the oldest and most appropriate name available. Based on phylogeography of M. pilosusin China, three lineages that correspond to distinct geographical populations were identified. Monotypic.
Distribution. S & E China (Beijing, Shaanxi, Shandong, Jiangsu, Anhui, Zhejiang, Jiangxi, Fujian, Hunan, Guizhou, Guangdong, Guangxi, Yunnan, Xizang, and Hainan I), C Laos (Khammouane Province), N Vietnam (from Lang Son, Nghe An, Quang Binh, and Bac Kan provinces), and recently reported from Meghalaya State in NE India. Given this recent record far away from its main distribution, this species might occur in suitable habitats in Myanmar and Thailand.
Descriptive notes. Head-body 51-65 mm, tail 35-55 mm, ear 11-22- 3 mm, hindfoot 13-3-17- 5 mm, forearm 52-1-63- 5 mm; weight 11-7-32.5 g (ranges from different sources). Compared with mainland specimens, 27 specimens from Hainan Island were smaller (forearm 48- 5-51 mm, tail 35-44 mm, ear 11-16- 2 mm, hindfoot 13-3— 16- 3 mm; weight 117-222 g), perhaps representing a subspecies. Rickett’s Big-footed Myotis has extreme large feet and very strong claws, well adapted for catching fish. Short fur is closely appressed to skin and velvety. Upperparts are drab, buffy gray-brown, with darker roots, and slightly darker on sides of head. Underparts are nearly off-white, with pale gray to white tips, and dark roots. Ears are medium brown and moderately large; anterior borders are smoothly convex but with well-defined notch at bases, bluntly pointed tips and straight posterior borders. Tragus is one-half the ear length and narrowly pointed. Muzzle is well covered with bristly whiskers. Tibiae are well haired above and below. Hindfeet are unusually large (c.80% the length oftibiae), with long, sharply pointed, pale, curved claws. Calcar is 9-10 mm and more than four-fifths the length of posterior border of uropatagium from foot to tip of tail. Uropatagium has some hair nearest to the body but no fringe on its margin. Wing membranes are dark brown and attach to ankle on ventral side of distal part of tibiae. Skull is medium-sized, with relatively broad rostrum and smooth dorsal profile. Anterior braincase does notrise sharply above rostrum, and there is only a very shallow concavity above posterior rostrum. Sagittal crest is poorly developed. Post-dental extension of palate is short and wide. Upper dentition is relatively weak; average length of upper tooth row (C-M?) is 8- 3 mm. Upper incisors are large, each with conspicuous supplementary cusp. Canines lack secondary cusps. P? is small, with single crown;it is situated in tooth row and usually in contact with C'. Crown area of P? is about one-half to two-thirds that of P%. P* displaced internally in tooth row and in close contact with P* which is about two-thirds the height of C' but has greater crown area. Upper molarsare typically myotodont. I, and I, are three-lobed from the front. C is about twice the height of Pail is about equal to or exceeds P, in height and crown area. P, is about one-half to two-thirds the crown area of P,, which is one-third to half that of C'. Condylo-basal lengths are 17-8-18- 8 mm; maxillary tooth row lengths are 8-2-8- 4 mm. Chromosomal complement has 2n = 44 and FN = 52.
Habitat. Strictly dependent on large areas of water (e.g. lakes, reservoir, and large still rivers) in lowland secondary forests, karst areas, and open habitats or heavily disturbed vegetation (Vietnam) at known elevations of 1400-3000 m.
Food and Feeding. Stomach of one Rickett’s Big-footed Myotis from Pu Mat, Vietham contained insects, but 97% of droppings from two specimens in Khammouan Limestone Area in Laos contained fish scales and a small number of insects. In a study of ¢.43 individuals from an area near Beijing, China, feces containedfish scales of Cyprinidae (Zacco, Carassius, Phoxinus) and insects (Coleoptera, Lepidoptera, Homoptera, Ephemeroptera, Hemiptera, Lepidoptera, and Hymenoptera). Scales of Z. platypus were the most abundantfish remains, and Coleoptera made up 70% of identifiable insects. These individuals flew back and forth above the water surface of the reservoir near their roosting cave.
Breeding. Mating of Rickett’s Big-footed Myotis took place in October—April. Sperm was stored until ovulation occurred after hibernation in May-June. Births ofsingle young probably occurred from mid-June to July, and lactating females were reported from a temple in Du-le Si inJune-September. Sperm was present in cauda epididymis from late September to early April but absent from testes from mid-November to late August.
Activity patterns. Flight of Rickett’s Big-footed Myotisis rapid and agile. They roost in caves. In a cave near Beijing, China, they hibernated from November to April. Echolocation calls have maximum frequency of 70-8 kHz, minimum frequency of 27-7 kHz, peak frequency of 40-6 kHz, average duration of 4-1 milliseconds, and average interpulse interval of 108-8 milliseconds. Calls of individuals in Hainan (forearm length 50 mm) have peak frequency of 50-4 kHz, those from Henan (forearm 58- 1 mm) 45-2 kHz, and those from Beijing (forearm 55-3-63- 5 mm) 41-9 kHz, which might reflect subspecific differences.
Movements, Home range and Social organization. Two female Rickett’s Big-footed Myotis were found together with Large Myotis (M. chinensis) at the entrance of Lan Cat Cave, Vietnam, which was small and cylindrical and surrounded by arable land. They were captured in August-mid October, near Beijing over a water reservoir in a warm temperate zone forest, dominated by oaks and pines, ¢. 8 km away from a cave with Greater Horseshoe Bats (Rhinolophus ferrumequinum), Rufous Tube-nosed Bat (Murina leucogaster), and Greater Myotis (M. myotis). Rickett’s Big-footed Myotis is more dependent on fish than smaller trawling species of Myotis and travels considerable distances to forage. It is present in the southern part of the Funiu Mountains (Henan, China) in summer only, suggesting they move to the area to access greater food resources. In the Beijing area, China, cave colonies have up to 1000-2000 individuals. Summer roosts (including maternity roosts) are found in May-June in buildings or caves, some of which are used in winter. Some individuals roost in clusters, but territorial males are scattered in the cave, and other individuals are chased away when they approach a territory. Rickett’s Big-footed Myotis often shares its roosts with other bats and swifts (Apodidae).
Status and Conservation. Classified as Near Threatened on The IUCN Red Last. Rickett’s Big-footed Myotis has low tolerance to human disturbance. It is highly dependent on water sources forits food, and water pollution in China is a major threat. Research is needed on population status, ecology, habitat status, and conservation threats. It occurs in Tianmu Mountain National Nature Reserve (China), Qomolangma National Nature Reserve (China), and Kim Hy Nature Reserve (northern Vietnam).
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description: Published as part of Don E. Wilson & Russell A. Mittermeier, 2019, Vespertilionidae, pp. 716-981 in Handbook of the Mammals of the World – Volume 9 Bats, Barcelona :Lynx Edicions on page 974, DOI: 10.5281/zenodo.6397752