Shell strongly dorsibiconvex, about 80% as long as wide; anterior commissure weakly uniplicate; ventral muscle field large, subcordate, slightly elongated, extending anterior to the midvalve and bisected by long median ridge terminating at about one third valve length from the anterior margin; dorsal interior with undivided cardinal process with a broad shaft on a high notothyrial platform; brachiophores stout, divergent at about right angle; dorsal median ridge terminated at about middle of a weakly impressed dorsal adductor muscle field.
Anterior commissure weakly uniplicate. Ventral valve sagittal profile gently convex with maximum height at about one third valve length from the umbo.
Anterior commissure uniplicate. Ventral valve with an erect, acuminate beak.
Anterior commissure uniplicate. Ventral valve lateral profile moderately convex with maximum height at about one third valve length from the umbo.
Nevertheless, assignment of individual species of Platystrophia (s.l.) to (1) uniplicate (Pl.
Dorsibiconvex with Spirifer-like shells, uniplicate shell; interareas low, weakly concave in cross-section, ventral interarea apsacline, dorsal interarea anacline; radial ornament costate; lateral margins of ventral sulcus and dorsal fold not covered by costae; fine hollow spines of high density covering the entire shell surface except interareas; ventral interior with teeth supported by long subparallel dental plates to define thickened elongately oval muscle field; cardinalia of two types: with well-developed notothyrial platform or with sessile septalium; cardinal process simple, blade-like; median septum variously developed; dorsal muscle field quadripartite.
Thus, the assignment of this genus with coarsely costate ornament, a strongly uniplicate anterior margin, and with deep exopuncta (which may be the remains of granulation) to this family remains tentative.
Platystrophiid with uniplicate or biplicate origination of costae in ventral sulcus; dorsal interior with well-developed notothyrial platform; brachiophores with massive basal parts; fulcral plates absent; anterior and posterior pairs of adductor scars closely spaced in the central part of the dorsal valve; median septum well developed, bisecting the adductor scars medially; adductor muscle impressions smooth.