In both superfamilies, the adaptations to this lifestyle involves modifications to the spines on their anterior prosomal appendages for raking through the substrate of their habitats.

[2] Due to the majority of specimens being incomplete, the internal topology of the Stylonuroidea is among the least well-resolved and supported in the Stylonurina and the Eurypterida at large.

This is mostly due to the poor fossil record of many of the genera included within the superfamily, for instance the single known specimen of Stylonurus powriensis lacks the anterior prosomal appendages and virtually all ventral structures.

Similar situations can be seen in many specimens, such as Stylonurella spinipes not preserving the metastoma or pretelson and telson and Pagea sturrocki lacking all dorsal structures.

For instance, the family Parastylonuridae is likely paraphyletic but it is retained as it is due to the lack of complete specimens of the genera included within it, Parastylonurus and Stylonurella.