|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Rhynchonellata - Orthida - Plectorthidae
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.
|L. E. Popov and L. R. M. Cocks 2014||Shell slightly dorsibiconvex to subequally biconvex with a variably developed uniplicate anterior commissure and finely fascicostellate radial ornament. Ventral valve with shallow sulcus anterior to mid-length. Ventral interarea apsacline with an open triangular delthyrium laterally defined by incipient delthyrial plates. Dorsal valve with orthocline interarea and shallow sulcus in the umbonal region reversed into a low median fold anterior to mid-length. Ventral interior with long, divergent dental plates and a strongly impressed, bilobed muscle field with narrow triangular diductor muscle scar raised anteriorly and slightly shorter than strongly impressed adductor muscle scars. Mantle canal system saccate with divergent vascula media. Dorsal interior with blade-like, anteriorly divergent brachiophores and a ridge-like cardinal process with a thickened shaft and a crenulated myophore, bisecting a low, subtriangular notothyrial platform. Dorsal median ridge low and short. Dorsal adductor muscle field gently impressed, quadripartite with a larger posterior pair of adductor scars.|