Diplothrix legata (Thomas 1906)

[Lenothrix] legata Thomas 1906, Ann. Mag. Nat. Hist., ser. 7, 17: 88.

Type Locality: Japan, Ryukyu Isls, Amami-oshima Isl.

Vernacular Names: Ryukyu Islands Tree Rat.

Synonyms: Diplothrix okinavensis (Namie 1909) .

Distribution: Japan, Ryukyu Isls of Amami-oshima, Tokun-oshima, and Okinawa (known by modern specimens only in north, but by Quaternary fossils from farther south on island, and from Miyako Isl, about 250 km SW of Okinawa; see Kawamura, 1989, 1991, 1994).

Conservation: IUCN – Endangered.

Discussion: Historical allocation of legata with either Lenothrix or Rattus is reviewed by Kawamura (1989). Phylogenetic relationship–discerned from molar occlusal patterns, cranial morphology, and body form–is close to Rattus and far from Lenothrix; "phylogeny of this unique genus will be sufficiently understood, when the fossil murids from China, India and Southeast Asia will be investigated in detail" (Kawamura, 1989:110). Analyses of mtDNA cytochrome b and nuclear IRBP gene sequences support morphological data in clustering D. legata with the species of Rattus used ( R. norvegicus, R. argentiventer, and R. rattus) and not with the other murines sampled (species of Apodemus, Micromys, Mus, and Tokudaia), and support the hypothesis that D. legata is a survivor from Pliocene and early Pleistocene immigrant ancestral population to the Ryukyus (Suzuki et al., 2000). Chromosomal data reviewed by Tsuchiya (1981). A review by Kaneko (1994) includes beautiful color photographs of live rats showing their long well-haired tail and long body guard hairs extending far beyond the dorsal coat, which are features common to many species of arboreal murines, particularly those in the Rattus Division.