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.
[3] A 2009 paper argued that the poor diversity of modern Archostemata, compared with the staggering evolutionary success of most other Coleoptera lineages, could be due to the lower efficiency of the thoracic locomotor apparatus, the absence of cryptonephric Malpighian tubules, and competition with other beetles more adapted to angiosperms.
[5][6] A partial phylogeny of Archostemata and early coleopterans, based on palaeontological data, from Boudinot et al.
[2] Tshekardocoleidae † Permocupedidae † Cupedidae Ommatidae Micromalthidae Myxophaga Adephaga Polyphaga According to Li et al. 2023;[1] archostematan families are in bold.
Tshekardocoleidae † Permocupedidae † Rhombocoleidae † Triadocupedinae † Ademosynidae † Schizophoridae † Trachypacus Helophorus Torridincola Omma Tetraphalerus Sikhotealinia Jurodes † Crowsoniellidae Micromalthidae Catiniidae† Notocupes† Priacma Paracupes Cupes Tenomerga Rhipsideigma Ascioplaga Distocupes