Yaeyama Pachyrhynchus Weevil

Pachyrhynchus infernalis

Japanese name: クロカダゾウムシ
Chinese name: 八重山球背象鼻蟲
English name: Yaeyama Pachyrhynchus Weevil
Origin: Ishigakijima, Iriomotejima

This species is the only representative of the genus Pachyrhynchus confirmed to occur in Japan, and it is found only on Ishigakijima and Iriomotejima. Members of this genus are primarily distributed across the Philippine islands, with several species also known from Lanyu (Orchid Island) and Ludao (Green Island) off southeastern Taiwan.

A notable characteristic of this genus is that their elytra are fused, making them flightless. In recent years, research has been exploring how Pachyrhynchus species dispersed from the Philippines to Lanyu, Ludao, and the Yaeyama Islands.

While many Pachyrhynchus species are known for their bright colors and intricate patterns, Pachyrhynchus infernalis is distinctively plain, with a completely black, unmarked appearance.

Related research:
Tseng, H-Y., W-S. Huang, M-L. Jeng, R.J.T. Villanueva, O.M. Nuñeza and C-P. Lin (2017). Complex inter-island colonization and peripatric founder speciation promote diversification of flightless Pachyrhynchus weevils in the Taiwan-Luzon volcanic belt. Journal of Biogeography.

30 Jun, 2025, Iriomote
10 Aug, 2023, Iriomote