|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||Age range and collections|
Orthothecida - Allathecidae
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. Y. Parkhaev and Y. Demidenko 2010||"Shell of elongated shape, with oval to rounded-triangular cross-section. Dorsal side strongly convex, ventral side flattened or slightly convex. Ornamentation represented by transverse ribs, equally prominent along whole perimeter of shell."|