[2][3][4] The Enoplea are considered to be a more ancestral group than the Chromadorea, and researchers have referred to its members as the "ancestrally diverged nematodes", compared to the "more recently diverged nematodes" of Chromadorea.

An enoplean is smooth or marked with fine lines, while a chromadorean may have rings, projections, or setae.

[6][7] Phylogenetic analysis of phylum Nematoda suggests three distinct basal clades, the dorylaims, enoplids and chromadorids.

The orders Triplonchida and Dorylaimida include plant-parasitic nematodes that are vectors of plant pathogens.

The orders Dioctophymatida, Trichinellida, and Muspiceida include parasites of vertebrates such as birds and mammals.