|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Rhynchonellata - Orthida - Glyptorthidae
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.
|G. A. Cooper 1956||Small to medium-sized for the genus, wider than long, with the hinge forming the greatest shell width or so narrowed as to be less than the width near the middle. Lateral margins ranging from straight and sloping medianly to gently convex ; anterior margin straight or slightly curved. Surface multicostellate, the costellae elevated and subangular and separated by spaces as wide or wider than the costellae. Three generations of costellae may be counted : a set originating at the beaks, a secondary set, few in number, intercalated near the middle and a ternary set appearing a short distance posterior to the margin. From 6 to 9 costellae appear in 5 mm. at the front margin depending on the amount of anterior intercalation. From 20 to 36 costellae may be counted on a valve. About 3 imbricating lamellae in the space of i mm. near the middle.
Pedicle valve in lateral profile with maximum convexity in the posterior half; in anterior profile broadly convex with moderately sloping sides. Umbo full, this fullness extended for the median length as an indistinct fold. Lateral slopes long but only moderately steep as most of the fullness is concentrated in the median area. Beak slightly incurved ; interarea nearly flat, short. Delthyrium narrow. Interior with short, thick dental plates ; moderately deep delthyrial cavity ; muscle field heart-shaped with adductor field slightly elevated, large diductor impressions but small adjustor scars.
Brachial valve most convex in the posterior half in lateral profile but broadly and gently convex and with the median part sulcate in anterior profile. Sulcus originating at the umbo, prominent, widening and deepening anteriorly, variable in depth and width. Sulcus with 2 costellae on the umbo, bifurcating in a short distance to produce 4, and this number augmented by intercalations of the ternary set near the front margin. Flanks moderately convex with short but fairly steep umbonal slopes and with lateral slopes becoming less steep anteriorly. Interarea short. Interior of brachial valve with short, stout brachiophores, prominent median ridge and large adductor field. The anterior adductor scars are each divisible into 2 impressions; the posterior scars small. Pallial marks not well preserved in either valve.