Mus (Mus) caroli Bonhote 1902

Mus (Mus) caroli Bonhote 1902, Novit. Zool., 9: 627.

Type Locality: Japan, Ryukyu (= Liukiu) Isls, Okinawa Isl.

Vernacular Names: Ryukyu Mouse.

Synonyms: Mus (Mus) boninensis Kishida 1926; Mus (Mus) boninensis Kuroda 1930; Mus (Mus) formosanus Kuroda 1925; Mus (Mus) kurilensis Kuroda 1924; Mus (Mus) ouwensi Kloss 1921 .

Distribution: Natural range probably from Ryukyu Isls (Kaneko, 1994) to Taiwan (M.-J. Yu, 1996, and Wang, 2003), S China (Fujian, Guangdong, Guizhou, Guangxi, Yunnan, Hainan Isl; Wang, 2003, and Zhang et al., 1997) and Hong Kong (Chandrasekar-Rao and Musser, 1993), Vietnam (Dang et al., 1994; also Cat Ba Isl, off north coast; Kuznetsov, 2000), Laos (Aplin et al., 2003 c; Smith et al., In Press), Cambodia, and Thailand (N of Isthmus of Kra; J. T. Marshall, Jr., 1977 a). Also recorded from Malay Peninsula (S Kedah State), Sumatra, Java, Madura, and Flores Isls in Nusa Tenggara, all places where it was likely inadvertently introduced (Musser and Newcomb, 1983).

Conservation: IUCN – Lower Risk (lc).

Discussion: Subgenus Mus . For synonyms see Kaneko and Maeda (2002). Morphologically similar to but easily distinguished (especially by cranial traits) from M. cervicolor (Macholán, 2001; J. T. Marshall, Jr., 1977 b); member of a clade containing M. cookii and M. cervicolor as assessed by sequences of several different genes (Graur, 1994; Lundrigan et al., 2002). This alignment also supported by combined analyses of morphological traits, DNA/DNA hybridization, and mitochondrial 12S rRNA sequences (Chevret et al, 2003). Multivariate morphometric analysis by Macholán (2001) of Thai and Vietnamese samples suggested significant morphometric differences between populations from the two geographic regions and Macholán speculated that the Mekong River may impede gene flow between them. Habitat use on Taiwan reported by Adler (1995). Reviewed by Corbet and Hill (1992), who doubted that ouwensi is synonymous with M. caroli . Sterile hybrid females were obtained from crosses between M. caroli and M. musculus (West et al., 1978). Genetic variation across mainland Southeast Asian range surveyed by Terashima et al. (2003). Aplin et al. (2003 c) illustrated a specimen of M. caroli collected near Hmawbe in C Burma (the same taxon was subsequently collected near Mawlamyine, Mon State; K. Aplin, in litt., 2004). Molecular analysis in the laboratory of Dr. H. Suzuki has confirmed the general relationship of this taxon to M. caroli (K. Aplin, in litt., 2004). The Burmese population, however, is much larger-bodied than typical M. caroli from farther east.

Musser and Carleton (1993:623) listed kakhyenensis, described by Anderson (1879) from a specimen collected in the Kakhyen Hills of W Yunnan, in the synonymy of M. caroli . It is an older name than caroli . J. T. Marshall, Jr. (1977 b:211, 1998:53) examined the holotype (body in fluid, skull missing) but without the skull could not identify it to species, declared the name indeterminate, and urged its suppression. Aplin (in litt., 2004) noted that "this seems insufficient grounds given the dual possibilities of recollecting at a known type locality and/or DNA recovery from an extant holotype." Molars recovered from cave sediments in Thailand document occurrence of M. caroli back to late Pliocene in that country Pliocene (Chaimanee, 1998).