Uromys siebersi Thomas 1923

Uromys siebersi Thomas 1923, Treubia, 3: 422.

Type Locality: Indonesia, Maluku Tengah, Pulau Kai Besar (Great Key Isl), Gunung Daab.

Vernacular Names: Great Key Island Uromys.

Distribution: Recorded only from Pulau Kai Besar in Kepulauan Kai (Ewab), between Seram Isl and the Aru Isls.

Discussion: Originally described as a species but subsequently treated as a subspecies of Uromys caudimaculatus (Ellerman, 1941; Rümmler, 1938) or synonym of U. caudimaculatus aruensis (Laurie and Hill, 1954) . In their revision of Uromys, Groves and Flannery (1994) identified siebersi as a taxon of "uncertain status" because they could not allocate it to any of the subspecies of U. caudimaculatus they recognized. Still known only by two skins and a single skull (Groves and Flannery, 1994), Thomas’s siebersi should be highlighted as a species. Among its diagnostic characteristics are very short tail relative to head and body length, small slit-like incisive foramina, and distinctly bowed skull (K. Helgen, in litt., 2004). The phylogenetic relationship of U. siebersi with samples of U. caudimaculatus along with the other recognized species of Uromys should be critically assessed in the context of a new taxonomic evaluation of geographic variation within samples now referred to U. caudimaculatus and Uromys itself. Uromys siebersi joins Melomys bannisteri as endemics of Pulau Kai Besar. The Kai Isls are in deep water and not on the continental shelf connecting Australia and New Guinea beneath the Arafura Sea, and any endemic species such as Melomys bannisteri and Uromys siebersi are likely the product of a longer evolutionary history in isolation than is true of faunas on continental shelf islands associated with Australia and New Guinea.