High-altitude diversification of a putative Singaporean-endemic rove beetle genus in the Eastern Himalaya (Coleoptera: Staphylinidae: Pselaphinae)

Abstract The pselaphine genus Prophilus Raffray, 1890 (Euplectitae: Trichonychini), historically considered a Sundaic lineage restricted to Singapore, is herein reported to occur in the Eastern Himalaya. This discovery represents a range extension of the genus over 3,000 km, bridging the equatorial tropics and the high-altitude temperate forests of Zayü, Xizang. The following new species are described: P. kangrikarpo sp. nov. , P. rima sp. nov. , P. sanggyog sp. nov. , and P. shangzayu sp. nov. Crucially, the Himalayan taxa possess 11-segmented antennae, a putative plesiomorphic character state in contrast to the 10-segmented antennae of their Singaporean congeners. These findings challenge the genus’s presumed endemism and support the ‘Assam Gateway’ hypothesis as a corridor for Eocene-Oligocene faunal exchange. In addition, an identification key to all known species is provided.