Myotis rufoniger (Tomes, 1858)

Synonymy. Vespertilio rufo-niger Tomes, 1858 . Type locality Shanghai, China. Myotis tsuensis Kuroda, 1922 . Type locality Tsushima Island, Japan. Myotis Watasei Kishida, 1924 . Type locality Manjhou, Pingtung, Taiwan. Myotis chofukusei Mori, 1928 . Type locality Hwanghae-Namdo, North Korea. Myotis rufoniger: Tate 1941 . First use of current name combination. Myotis formosus: Findley 1972 (part). Name combination.

Myotis formosus: Corbet & Hill 1992 (part). Name combination. Myotis formosus rufoniger: Koopman 1994 . Name combination. Myotis formosus: Kawai et al. 2003 . Name combination.

Myotis watasei: Lin et al 2004 . Name combination.

Myotis formosus rufoniger: Simmons 2005 . Name combination. Myotis formosus tsuensis: Simmons 2005 . Name combination.

Myotis formosus watasei: Simmons 2005 . Name combination.

Myotis formosus watasei: Jiang et al. 2010 . Name combination. Myotis rufoniger watasei: Cheng et al. 2010 . Name combination. Myotis formosus: Kim et al. 2011 . Name combination.

Myotis cf. formosus: Ruedi et al. 2013 . Name combination.

Taxonomic remarks. As for previous species also belonging to the Chrysopteron subgenus, we only outline here the main distinguishing characters between formosus and rufoniger and suggest the reader to consult the complete taxonomic account on this subgenus for more details (Csorba et al. 2014). Notice that Kim et al. (2011) published the complete mitochondrial genome of M. rufoniger from South Korea, under the name “ Myotis formosus ”.

Distribution. M. rufoniger is apparently also a rare species that has only been collected in a handful of localities. It has been found in northern Vietnam and Laos, Taiwan, throughout China, North and South Korea and on Tsushima Island in the Japanese archipelago (see details in Csorba et al. 2014).

Measurements. See Table 4 for measurements of the specimens from Taiwan.

External morphology. M. rufoniger is a second, large species of Oriental Myotis with a striking orange and black patterning of the wing membranes similar to that of M. formosus . However, unlike the latter, its wooly fur is darker, more rusty orange (both above and below), and hairs on the dorsal parts are tricolored (slate grey at the base, yellowish in the middle and dark brown near the tips), which gives a smoked appearance to its dorsal pelage (see figure at pages 100 and 112 in Lin et al. 2004). Other typical external characters include the ears (which are orange bordered extensively with black along the edge of the conch), and the nose tip, thumbs and feet (which are also entirely black, not orange). The face and uropatagium are essentially orange, but darker than in formosus . Wings are attached to the base of the outer toe, and are furred along the body. Feet are strong and hairy, about one third of tibia length. The tragus is sickle-shaped, bending forwards, and is relatively pointed.

Skull morphology. The dimensions of the skull and teeth of M. rufoniger are slightly smaller than those of M. formosus (see Table 4). Differences include a more angular posterior part of the braincase, and the presence of marked occipital and lambdoid crests (Fig. 8 d). The second upper premolar is only slightly smaller than the first, and usually only barely displaced from toothrow (Fig. 8 d), and hence visible when viewed from profile (unlike in M. formosus, Fig. 8 c).

Natural history. Myotis rufoniger is also an uncommon bat whose biology and habitat requirements are largely unknown. In Korea and Taiwan (Lin et al. 2004), it is found in mountain forests, where is roosts in caves, and a female with young was reported in August.