The Archostemata are the smallest suborder of beetles, consisting 45 living species in five families. They are an ancient lineage with a number of primitive characteristics. Antennae may be thread-shaped (filiform) or like a string of beads (moniliform). This suborder also contains the only beetles where both sexes are paedogenic, Micromalthus debilis. Modern archostematan beetles are considered rare, but were more diverse during the Mesozoic. The term "Archostemata" is used more broadly by some authors to include both modern archostematans as well as stem-group beetles like "protocoleopterans", which some modern archostematans closely resemble to due to their plesiomorphic morphology. Genetic research suggests that modern archostematans are a monophyletic group. Some genetic studies have recovered archostematans as the sister group of Myxophaga. Taxonomy There are five extant families. Family Crowsoniellidae Iablokoff-Khnzorian, 1983 Family Cupedidae Laporte, 1838 Family Micromalthidae Barber, 1913 Family Ommatidae Sharp and Muir, 1912 Family Jurodidae Ponomarenko, 1985 See also List of subgroups of the order Coleoptera References External links Tree of Life - Archostemata Insect suborders Extant Permian first appearances Taxa named by Hermann Julius Kolbe