Leopoldamys siporanus (Thomas 1895)

[Leopoldamys] siporanus (Thomas 1895), Ann. Mus. Civ. Stor. Nat. Genova, 34: 11.

Type Locality: Indonesia, Kepulauan Mentawai, Pulau Sipora.

Vernacular Names: Mentawai Archipelago Leopoldamys.

Synonyms: Leopoldamys soccatus (Miller 1903).

Distribution: Endemic to Mentawai Arch.; islands of Siberut, Sipora, North Pagai, and South Pagai.

Conservation: IUCN – Vulnerable.

Discussion: Originally described as a species, subsequently recognized as such by Ellerman (1941), but later treated as a subspecies of either Rattus sabanus (Chasen, 1940) or R. edwardsi (Ellerman, 1961). In its morphology, L. siporanus is distinct from either of those species. Where it fits within the web of phylogenetic relationships among species of Leopoldamys has yet to be determined. Leopoldamys siporanus might be closely allied to one of the extant species, but because evolutionary history of the genus is documented back to late Pliocene in Indochina (Chaimanee, 1998), L. siporanus might represent an early lineage isolated in the Mentawai Arch. and within a phylogenetic pattern of relationships. Systematic revision of Leopoldamys using a suite of morphological character sets along with molecular data would be revealing. Leopoldamys siporanus joins Maxomys pagensis, Chiropodomys karlkoopmani, Rattus lugens, Iomys sipora, Hylopetes sipora, Petinomys lugens, Callosciurus melanogaster, Sundasciurus fraterculus, and Lariscus obscurus as part of the rodent fauna endemic to the Mentawai Arch.