|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.
|P. Jell 1997||Dorsal disk covered by gently convex polygonal plates (arrangement unknown). Arms five, circular in section, with three columns of dorsal plates. Dorsal arm and disk plates all with long stout spines (one per plate although some disk plates may bear more than one). Proximal Ambb dorsally short (rad.), opposite across radial line, bevelled proximally and distally into interAmbb sutures to produce deep clefts across the arms between short (rad.) ridges. Abradial edge of Adambb with vertical row of two or three long spines projecting ventrolaterally. Ventral surface unknown.|