460.

Csorba’s Myotis

Myotis csorbai

French: Murin de Csorba / German: Csorba-LangfulRfledermaus / Spanish: Ratonero de Csorba

Other common names: Csorba's Mouse-eared Bat, Csorba’s Mouse-eared Myotis

Taxonomy. Myotis csorbai Topal, 1998,

about 30 km S of Pokhara town, 4 km E of Syangja, 1300 m, Syangja District, Nepal.

Subgenus Myotis; siligorensis species group. Myotis csorbai is morphologically very similar to M. longipes, and its sister-group is the capaccinii species group. Records from NE India (Meghalaya), S China (Sichuan, Chongqing, Guizhou, and Guangxi), and C Laos need additional taxonomic assessment to confirm their identity as M. csorbai . Monotypic.

Distribution. Only definitely known from Nepal.

Descriptive notes. Head-body 37- 3-41 mm, tail 32-42 mm, ear 11-7-16- 4 mm, hindfoot 6-:6-8- 9 mm, forearm 33-7-37- 5 mm; weight 3-4- 6 g. Csorba’s Myotis is generally similar to the Annamit Myotis (M. annamiticus) and smaller than the Kashmir Cave Myotis ( M. longipes). Upperparts of Csorba’s Myotis are dark brownish black; underparts are dull grayish. Ears and membranes are translucent smoky gray. Wing attaches at middle of metatarsus and is sparsely covered with thin hairs on upper side. Calcar is long and thick, without lobe. Uropatagium is hairless. Baculum is less than 0-5 mm long, 0-27 mm in maximum width, and almost triangular with moderate rounded notch at base. Upperside is slightly concaved on basal one-third and shallowly convexed in proximal one-third. Shallow depression occurs on ventral side of bone. Skull is small, with bulbous braincase that is distinctly elevated above flattened rostrum. Sagittal and lambdoid crests are scarcely evident. Zygomata are wide. Short coronoid process of mandible has vertical anterior border and horizontal posterior border. I? and I” are distinct and bicuspidate. C' is weak and about equal to height and ¢.50% of crown area of P*. P?> and P° are minute. P* is one-half the crown area of P% P? slightly displaced internally from tooth row. C, is smaller compared with C'. It is about twothirds the crown area of P,. Molars are characteristically larger. Condylo-canine lengths are 11- 1-12 mm; maxillary tooth row lengths are 4:6-5- 5 mm.

Habitat. Subtropical secondary forests at elevations of 1300-1700 m.

Food and Feeding. Csorba’s Myotis were observed hunting above a river and occasionally the riverbank. Flight typically involves slow circles at 10-30 cm above water surface, rarely above 1-3 m on the riverbank. Flight pattern is similar to that of Daubenton’s Myotis ( M. daubentonii).

Breeding. Most female Csorba’s Myotis captured in May had near-term embryos in right uterine horns. One was nulliparous, and some probably gave birth shortly after capture. Difference between average weight of pregnant and non-pregnant females was 1-4 g, suggesting very relatively high neonatal weight.

Activity patterns. Csorba’s Myotis is nocturnal and roosts in caves. It was found roosting inside crevices and small holes. Some specimens were collected in a net in front of a cave, surrounded by subtropical secondary forest. Csorba’s Myotis left the cave early before total darkness in summer.

Movements, Home range and Social organization. Holotype and four paratypes of Csorba’s Myotis were collected from a colony of ¢.50-60 individuals. Great Himalayan Leat-nosed Bats (Hipposideros armiger) and Schreibers’s Long-fingered Bats ( Miniopterus schreibersii) also used the Kailash cave.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. There is no recent information on extent of occurrence, ecological requirements, threats, and conservation status of Csorba’s Myotis . Its habitatis threatened by deforestation from logging, agriculture, and mining. It does not occur in any protected areas. There are public awareness campaigns and local conservation projects targeting the cave where the type series was collected.

Bibliography. Acharya et al. (2010), Amador et al. (2018), Bates & Harrison (1997), Borisenko, Kruskop & Ivanova (2008), Csorba & Thapa (2016), Csorba et al. (1999), Kruskop & Tsytsulina (2001), Molur et al. (2002), Pearch (2011), Ruedi et al. (2013), Simmons (2005), Thapa, A. & Thapa (2010), Thapa, S. (2014), Thapa, S., Shrestha et al. (2012), Topal (1998).