Miniaturized
Guides
Sphaeriusidae
Minute Bog Beetles
Sphaeriusidae is a family of minute myxophagan beetles (Coleoptera: Myxophaga) known as living fossils due to their exceptional morphological conservatism spanning at least 100 million years. The family contains three genera: the extinct †Burmasporum, the newly defined Bezesporum (known from both Burmese amber and extant Southeast Asian fauna), and Sphaerius, which has worldwide distribution. These beetles are characterized by miniaturized, shiny, blackish, hemispherical bodies and specialized riparian habits. Their species diversity and fine-scale morphological variation have been historically underestimated due to their small size and cryptic habits.