Archostemata

The Archostemata are the smallest suborder of beetles, consisting of 50 living species in five families and over 200 described fossil species. 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

Phylogeny
A partial phylogeny of Archostemata and early coleopterans, based on palaeontological data, from Boudinot et al. 2022.

According to Li et al. 2023; archostematan families are in bold.