|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Rhynchonellata - Spiriferida - Trigonotretidae
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.
|J. B. Waterhouse 1987||Transverse shells with well formed plicae and high primary costae, well defined concentric growth lamellae, fold high with narrow crest, adminicula short and well spaced, ventral muscle field broad|