Wednesday, December 19, 2012

[Mammalogy • 2011] Glischropus bucephalus | Indochinese Thick-thumbed Bat | ค้างคาวมือปุ่มอินโดจีน •A new species of Glischropus (Mammalia: Chiroptera: Vespertilionidae) from the Indochinese Subregion

Glischropus bucephalus | Indochinese Thick-thumbed Bat Close-up of side of head; paratype; HNHM 2006.34.37, 1 January 2006. G Csorba

Within the tribe Pipistrellini, the genus Glischropus is very close to the genus Pipistrellus both in its external morphology and chromosomal features but can be unequivocally distinguished from the latter by the presence of thumb pads and the position of the second incisor. One of the two known species, G. tylopus was thought to have a wide distribution range from Myanmar to the Philippines, while the other, G. javanus is only known from Java. Recently collected Cambodian specimens of Glischropus are distinguished from their congeners by longer forearm and cranial features (the shape of the skull and the upper incisors and certain craniodental measurements) and are consequentially, described here as a new species. Based on thorough examination of the available museum material, it can be concluded that all specimens of G. tylopus previously collected in the Indochinese zoogeographic subregion are in fact representatives of this new species, while G. tylopus in a strict sense is restricted in the mainland to south of the Isthmus of Kra.

Key words: Southeast Asia, taxonomy, thick-thumbed Bat

Etymology. The specific epithet (meaning “ox-headed” in English) refers to the massive and elevated frontal region of the new species relative to its congeners. The proposed English name is ’Indochinese Thick-thumbed Bat’.

Family: Vespertilionidae (vesper bats)

Distribution: Cambodia, Laos, Thailand, and Vietnam

Distribution.  This is the first published record of  Glischropus from Cambodia. In Myanmar, Bates  et al. (2005) cited a single record from Blanford (1888–91) who mentioned G. tylopus from the Karen Hills. No further data was given in these papers. 
In Thailand, Lekagul & McNeely (1977) referred to G. tylopus as “...found throughout the country whenever there are forests. It is rare.” but provided skull photographs of a specimen from Borneo (stored in the American Museum of Natural History Museum, New York) which clearly shows the cranial features of G. tylopus sensu stricto. However, Yenbutra & Felten (1986), in listing bat specimens in the Thai national reference collection (TISTR) in Bangkok and the Senckenberg Museum in Frankfurt, mentioned only a single locality for G. tylopus in the country: Bang Lan Dan in Yala Province, peninsular Thailand. As two other Thai specimens collected south of the Isthmus of Kra (studied in the collections of PSU and HNHM) represent G. tylopus, while one individual caught in Chantaburi Province north of this zoogeographic border proved to be G. bucephalus n. sp., the specimen mentioned by Yenbutra and Felten (1986) likely also represents G. tylopus sensu stricto.

In Lao P.D.R., Guillen et al (1997) and Francis et al. (1999) mentioned the occurrence of Glischropus from two areas (Phou Khao Khoay NBCA and Theun-Hinboun) without further details. However, forearm length measurements in 8 specimens from Laos —ranging from 32.7 to 34.6 mm— suggest these individuals represent G. bucephalus n. sp. (Francis, pers. comm.). Judging from a skull drawing and forearm measurements of five individuals (32.8–35.7 mm) attributed to G. tylopus by Borissenko and Kruskop (2003: pp. 174, 184), G. bucephalus n. sp. also occurs in the Cat Loc area of Lam Dong Province, Vietnam. This is the only published record of the genus from the country to date (Dang Ngoc Can et al. 2008). 

The DNA-barcoded PSU specimen of G. tylopus from peninsular Thailand differed by an average of c. 11% from the three  Glischropus specimens published in Francis  et al. (2010) (Francis, pers. comm.). The latter (assigned in the above paper as G. tylopus) originated from Vietnam and Laos and most likely represent the new species. These genetic data strongly support the view that G. bucephalus n. sp. is widely distributed in the Indochinese Subregion north of the Isthmus of Kra while specimens from peninsular Thailand represent G. tylopus.

Csorba, G. 2011. A new species of Glischropus from the Indochinese Subregion (Mammalia: Chiroptera: Vespertilionidae). Zootaxa. 2925: 41–48