Apterocyclus munroi Sharp 1909

Apterocyclus munroi is a species of stag beetle in the family Lucanidae. It was found on the island of Kauai in the Hawaiian Islands in 1897.

Four specimens of Apterocyclus munroi were collected on Kauai in 1897, and the species description was published in 1908. No specimens have been identified since 1897, and the species may now be extinct.

Mizunuma (2000) indicated that he considered the synonymy with Apterocyclus honoluluensis to be incorrect based on the dentate protibiae that are more similar to those of Apterocyclus waterhousei, and that the species might be distinct. We agree with this hypothesis. The protibiae of Apterocyclus munroi are externally toothed giving a unique bidentate appearance to the apex (Fig. 5), but the basal two-thirds of the external margin varies from weakly serrate to more or less entire (as in the holotype of Apterocyclus adpropinquans, Fig. 6). The protibiae of Apterocyclus waterhousei are much wider throughout their length. The scattered long setae on the elytra, especially near the apex, and projected, apically expanded clypeus will readily distinguish Apterocyclus munroi from the remaining species.

Sharp (1908) described Apterocyclus munroi from specimens collected “above Kaula” in 1897, but the identity of this locality is not clear. The holotype of the synonym Apterocyclus adpropinquans is reported to be from Makaweli at 2-3000’. No recent specimens with more complete locality data have been studied.