|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Strophomenata - Strophomenida - Sowerbyellidae
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.
|C. M. O. Rasmussen et al. 2012||Shell large, equally biconvex in profile. Transverse to suboval outline. Cardinal extremities alate. Hinge line bends laterally in anterior direction. Ventral interarea high, catacline. Delthyrium partially covered. Dorsal interarea low, orthocline to hypercline. Notothyrium covered by chilidium. Ornament of numerous thin costellae interrupted by accentuated costae and broad, wavy rugae. Ventral interior with small teeth, not supported by dental plates. Dorsal interior with a trifid, undercut cardinal process. Socket ridges long and wide. Very short, posteriorly developed, median septum with one pair of narrowangled side septa developed as an anterior extension of the median septum.|