475.

Russian Myotis

Myotis petax

French: Murin de |' Altai / German: Sibirien-Wasserfledermaus / Spanish: Ratonero de Altai

Other common names: Eastern Water Myotis, Sakhalin Myotis,

Taxonomy. Myotis petax Hollister, 1912,

“Kosh-Agatch, Chuisaya Steppe, Altai District, Siberia [Russia]; Altitude 7300 feet [= 2225 m].”

Subgenus Myotis; macrodactylus species group (4 species). Myotis petax has been considered a subspecies of M. daubentonii, but molecular and morphological data support its recognition as a distinct species. Genetic data indicate that M. petax is closer to other East Asian Myotis (e.g. M. pilosus, M. fimbriatus, and M. macrodactylus). Taxon abei has been recognized as a distinct species, butit is a junior synonym of nominate petax based on morphology and molecular data. Subspecies loukashkini tentatively includes chasanensis, pending additional comparison. Three subspecies recognized.

Subspecies and Distribution.

M.p.petaxHollister,1912—AltairegionofCRussiaandNEKazakhstan;possiblyinOmskregionofRussiaandNWChina,butspecimensarenotavailable.RangelimitsunclearasthisspeciesandDaubenton’sMyotis(M.daubentonii)maybefoundthere.

M.p.loukashkiniShamel,1942—WRussiafromSayanregiontoAmurregion,NMon-golia,andNEChina(Heilongjiang,Jilin,andNeiMongol).

M. p. ussuriensis Ognev, 1927 — Russian Far East (including Sakhalin I), Korean Peninsula, Japan (Hokkaido), and Kuril Is; probably also in NE China.

Descriptive notes. Head—-body 40-54- 2 mm, tail 27-41 mm, ear 9-1-15- 3 mm, hindfoot 8:3—- 12 mm, forearm 34-1-38- 3 mm. Fur of the Russian Myotisis silky and short. Dorsal pelage is grayish brown to dark brown; venteris paler grayish white to brownish gray. Naked parts of face, ears, and membranes are grayish brown, and membranes are semi-transparent. Ears are relatively long and slender; tragus is slender, straight, and ¢.50% the ear length. Uropatagium extends from ankle nearly to tip of tail (tail covered exceptlast free vertebra); calcar lacks keel but has terminal lobe. Wings attach at metatarsus of first toe. Hindfeet are comparatively large. Baculum is twice the length of that of Daubenton’s Myotis (1-2- 1-5 mm long) and does not distinctly narrow attip; tip is bluntly rounded, and base is about equal in width to shaft, with apparent bifurcation; ventral groove runs length of shaft. Rostrum is relatively wide; cranial width is greater than one-half the skull length; upper and lower tooth rows are shorter, braincase 1s lower, and rostral and canine widths are larger than in Daubenton’s Myotis; P* is small and in tooth row; C, is low and small; upper molars have small protocones; and lower molars are myotodont. Chromosomal complement has 2n = 44 and FN = 52 (Korea) or 2n = 44 and FN = 50 (Russian Far East).

Habitat. Temperate woodlands, particularly near bodies of water, in lowland regions (at least on Hokkaido, Japan).

Food and Feeding. In Japan, Russian Myotis appear to prey more readily on aquatic insects above water than terrestrial insects. They forage over Lake Baikal, but in Altai region, they were observed flying above meadows or in birch groves but not over water, although it could not be determined definitively if they were feeding. They flew 2-6 m aboveground or occasionally right above grass and made sudden loops or steep dives from time to time.

Breeding. Lactating Russian Myotis were captured in late July to early August in Japan, births probably occur in July, and enlarged testes were observed in early August.

Activity patterns. Russian Myotis are nocturnal, spending the day roosting reportedly in tree cavities, under bridges, or in a sluiceway. They hibernate in winter. Call shape is steep FM sweep, with end frequency averaging 37-8 kHz and peak frequency averaging 49-5 kHz in Japan and peak frequencies of 47-48 kHz in Russia.

Movements, Home range and Social organization. Russian Myotis roost in small groups, and females form maternity colonies during breeding season, with up to 30 individuals recorded under a bridge. A colony mixed with Big-footed Myotis ( M. macrodactylus) was reported.

Status and Conservation. Not assessed on The IUCN Red List. The Russian Myotis was recently separated from Daubenton’s Myotis, which is classified as Least Concern. The Russian Myotis is widespread and does not seem to face any major threats.

Bibliography. Akasaka, Akasaka & Nakamura (2012), Akasaka, Nakano & Nakamura (2009), Bogdanowicz (1994), Datzmann et al. (2012), Kruskop (2003, 2004), Kruskop et al. (2012), Matveev (2004), Matveev et al. (2005), Ohdachi et al. (2009), Ruedi et al. (2013), Son Sung-Won et al. (1997), Tiunov & Makarikova (2007), Wang Lei et al. (2010).