|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Rhynchonellata - Orthida - Archaeorthidae
It was recombined as Cyrtonotella subfissicostata by Williams (1962); it was recombined as Cyrtonotella subfissicosta by Candela and Harper (2014).
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|A. Williams 1962||Semi-elliptical to subquadrate, unequally biconvex to concavo-convex Cyrtonotella with acute angles in immature growth-stages and with a gently convex pedicle valve and a sulcate brachial valve that is slightly convex umbonally and probably gently concave in adult forms; ornamentation fascicostellate with about 13 costeUae per 5 mm. antero-medianly; ventral muscle-scar short, about oneninth as long as the pedicle valve with an acutely triangular adductor track ending in a small median boss, and widely splayed diductor scars not extending very much beyond the traces of abbreviated dental lamellae; cardinal process bulbous posteriorly, passing anteriorly into a broad, low, median ridge, brachiophores short, widely divergent.|