|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||Age range and collections|
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|M. R. Smith and J.-B. Caron 2015||Recovered by cladistic analysis and diagnosed by a swollen head, dorsal spines, and the differentiation of the anterior trunk and trunk appendages|