Most molecular phylogenetic studies of beetles (order Coleoptera) using 18S rDNA have recovered the suborders Adephaga and Polyphaga as sister groups, together sister to the suborders Myxophaga and Archostemata, with Archostemata alone or in combination with Myxophaga as the closest relative of all other beetles.
The 16 superfamilies and 168 families of extant beetles are separated into four suborders: Adephaga (~35,000 species), Archostemata (~35 species), Myxophaga (~65 species), and Polyphaga (~315,000 species) (Lawrence and Newton, 1995; Arnett and Thomas, 2000; Arnett et al.
However, an arrangement with Archostemata as sister to all other beetles, Myxophaga and Polyphaga as sister groups, and Adephaga as sister to Myxophaga and Polyphaga, is favored by recent morphological studies (Beutel and Haas, 2000; Beutel, 2005).
Most of their extensive analyses recovered Adephaga and Polyphaga as sister groups, and the suborders Myxophaga and Archostemata grouped together as sister to a clade comprised of Adephaga and Polyphaga.
When Coleoptera and each of its constituent suborders were constrained to be monophyletic in a parsimony (MP) analysis, Archostemata was recovered in a position sister to the remaining beetles, Adephaga and Polyphaga were sister groups, and Myxophaga was recovered in a position sister to Adephaga and Polyphaga.
Analyses under Bayesian (BI) and maximum likelihood (ML) inference recovered Adephaga and Polyphaga as sister groups, and Archostemata alone or in combination with Myxophaga as the closest relative of ali other beetles.