Blackburnia

The Hawaiian Islands are a string of islands increasing in age from the "big island" of Hawaii in the southeast the youngest, at 500,000 years old, with successively older islands toward the northwest. Kure Atoll, in the far northwest of the Hawaiian chain, has an estimated age of 28 to 30 million years. The beetles of Blackburnia have been successively colonizing and proliferating these islands since the Miocene period, 5 to 23 million years ago, and there are now more than 130 extant species of Blackburnia endemic to the Hawaiian Islands.

The species of Blackburnia are divided into four subgenera. The species Blackburnia mandibularis, with its own subgenus, Protocaccus, is a sister taxon to the other groups. It lives and breeds along streams in riparian moss on the island of Kauai.

The next clade to diverge in the evolutionary tree is Colpocaccus, with four flight-capable species.

The subgenera Blackburnia and Metromenus are monophyletic sister taxa. The subgenus Blackburnia has about 57 species, based on a flight-capable ancestor. Its species are the most morphologically diversified of the four subgenera. The subgenus Metromenus contains about 71 flightless species.

These 140 species belong to the genus Blackburnia: