Myotis macrodactylus

476.

Big-footed Myotis

Myotis macrodactylus

French: Murin macrodactyle / German: Ostasiatische Wasserfledermaus / Spanish: Ratonero macrodactilo

Other common names: Japanese Large-footed Bat

Taxonomy. Vespertilio macrodactylus Temminck, 1840,

“Le Japon [= Japan].”

Subgenus Myotis; macrodactylus species group. See M. petax. Myotis macrodactylus has been treated as a subspecies of M. capaccinii, but its species status is supported by morphology and genetic data. Three subspecies recognized.

Subspecies and Distribution. M.m.macrodactylusTemminck,1840—NEChina,N,SKoreanPeninsula(includ-ingJejuI),andmostofJapan(includingSado,Oki,Tsuslima,lk,Goto,Osumi,andAmami-OshimaIs).

M.m.continentalisTiunov,1997—RussianFarEast.

M. m. insularis Tiunov, 1997 — S Sakhalin I.

Descriptive notes. Head—body 40-71 mm, tail 29-49 mm, ear 12-16- 2 mm, hindfoot 9-13 mm, forearm 33-642 mm; weight 6-8 g. Fur of the Big-footed Myotis is soft and short. Dorsal pelage is frosted dark grayish brown (hairs with dark blackish brown bases and glossy light grayish brown tips); venteris paler grayish but becomes more yellowish white toward abdomen and groin. Bare parts of ears, face, and membranes are pale blackish brown. Ears are slender and moderately long, with rounded tips and smoothly outturned central anterior margins; they are concave up to one-third of posterior margins and convex on lower one-third of posterior margins. Tragus is narrow and taller than one-half the ear length, being widest at base, crescent-shaped, and pointed at tip. Wings attach to ankle, uropatagium is covered in sparse downy hair, and posterior border is fringed with fine hair. Baculum is generally Yshaped, barely tapering toward broadly roundedtip; venteris deeply concave along entire length; and base is bifurcated. Skull is robust and large, with slightly convex braincase; sagittal and lambdoidal crests are weakly developed; rostrum is short and low; forehead rises abruptly from rostrum; C' is tall; P? is very small and in tooth row; C, is relatively low; and P, is small and in tooth row. Chromosomal complement has 2n = 44 and FNa = 50 or 52 (Korea and Japan).

Habitat. Areas surrounding subterranean roosting sites near permanent bodies of water.

Food and Feeding. Big-footed Myotis feed mostly on Diptera, Trichoptera, and Lepidoptera, with body lengths of 7-20 mm. Spiders are regularly found in diets. They are fast, erratic, and low flying, often observed foraging in woodlands or over open water, (e.g. fast-moving streams,rivers, lakes, and reservoirs).

Breeding. The Big-footed Myotisis seasonally monoestrous and has delayed fertilization. It breeds in autumn, and fertilization is delayed until after hibernation. Females give birth to one young in July-August. Most females have theirfirst young at the end of their second year. Females breed every year, and pregnancy ratio of adult females is very high. At least one female bred at 15 years old. Maximum longevity is 19 years.

Activity patterns. Big-footed Myotis typically roost in caves, abandoned mines, tunnels, bomb shelters, and occasionally rock crevices, preferring humid roosts. They leave roosts early before dark to forage through the night. They hibernate in November— March. Calls have steep FM sweeps, with average start frequencies of 62:6-81-3 kHz, end frequencies of 40-8-43-6 kHz, peak frequencies of 45-8-52-9 kHz, interpulse intervals of 55-5-86-3 milliseconds, and durations of 5:3-7-1 milliseconds in Jilin, China. On Hokkaido, recordings had an average start frequency of 82-4 kHz (54-1- 91-7 kHz), end frequency of 39-4 kHz (37-8-50-1 kHz), peak frequency of 49-2 kHz (45-51-8 kHz), and duration of 65-8 milliseconds (44-144 milliseconds). Recordings based on five samples in South Korea had an average peak frequency of 49 kHz (45-2— 52-7 kHz), pulse interval of 66-3 milliseconds (53-2-71-5 milliseconds), and duration of 3-1 milliseconds (2-1-3-8 milliseconds).

Movements, Home range and Social organization. Male and female Big-footed Myotis roost together throughout much of the year. Maternity colonies with tens to hundreds of individuals are formed in summer. In spring and autumn, males and females tend to separate. They also form clusters with other bat species during the breeding season, including GreaterJapanese Horseshoe Bats (Rhinolophus nippon), LittleJapanese Horseshoe Bats (R. cornutus), Asian Long-fingered Bats (Miniopterusfuliginosus), Hilgendorf’s Tube-nosed Bats (Murina hilgendorfi), Far Eastern Myotis (M. bombinus), Ikonnikov’s Myotis (M. tkonnikovi), and Russian Myotis (M. petax). Small numbers of female Big-footed Myotis join maternity colonies of another speciesto give birth and rear their young. Females roosting with other species and males might obtain increased thermoregulatory advantage. In winter, Big-footed Myotis hibernate in small clusters or alone in crevices and rocky holes in caves, but they also share hibernacula with other species, including Greater Horseshoe Bats (Rhinolophus ferrumequinum), Far Eastern Myotis, Ikonnikov’s Myotis, Alashanian Pipistrelles (Hypsugo alaschanicus), and Asian Long-fingered Bats.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Bigfooted Myotis is widespread and relatively common and does not appear to have any major threats currently.

Bibliography. Abe et al. (2005), Ando et al. (1980c), Chung Chul-Un, Han Sang-Hoon, Lim Chun-Woo et al. (2010), Findley (1972), Fukui et al. (2004), Harada & Yoshida (1978), Harada et al. (1991), Jo Yeong-Seok et al. (2018), Kawai et al. (2003), Lee Jung-Hun (2003), Lee Jung-Hun & Mori (2004), LiuYing, Jin Longru et al. (2009), Luo Jinhong et al. (2012), Maeda (1976), Ohdachi et al. (2009), Ono & Obara (1994), Park Si-Ryong & Won Pyong-Oh (1978), Tiunov (1997), Tsytsulina (2008i), Son Sung-Won et al. (1995), Wang Lei et al. (2014), Xiao Yanhong et al. (2018), Yoo & Yoon Myung-Hee (1992), Yoshiyuki (1989).