|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||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.
|A. B. Smith and S. Zamora 2013||Stem polyplated; basal cup of large sutured plates; theca above the cup with five recumbent ambulacra spiralling clockwise away from an apical peristome. Ambulacra composed of biserial flooring plates lacking direct connection with the body chamber, and sheets of primary cover plates and very small secondary cover plates. Interambulacral zones are also spiral, composed of sheets of plates that could be expanded and contracted concertina-like.|