|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Strophomenata - Strophomenida - Strophomenidae
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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, subrectangular in outline and with the hinge forming the widest part; sides gently oblique; anterolateral extremities narrowly rounded; anterior margin gently convex to truncated. Surface finely costellate, 4 to 6 costellae in a millimeter at the front margin of an adult.
Pedicle valve strongly convex in lateral profile, the greatest convexity located at about the middle ; anterior profile domed and with steep sides but the median part depressed by a sulcus. Visceral region nearly flat in profile; geniculated part narrowly rounded; trail gently convex in lateral profile. Visceral region gently convex ; trail moderately long and marked by a prominent sulcus. Flanks of trail bounding sulcus rounded and somewhat swollen.
Brachial valve gently concave, the deepest part located near the place of geniculation. Visceral region gently concave. Trail short, marked medianly by a low and inconspicuous fold. Muscle area narrowly arrow shaped, moderately thickened.
|A. Williams 1962||Subquadrate Cyphomena, about two-thirds as long as wide, strongly concavo-convex and sharply geniculate dorsally at about the 7-mm. growth-stage, with a well-developed median sulcus and a complementary fold in the ventral and dorsal portions of the geniculate trail; ornamentation consisting of fine costellae, numbering 5 per millimetre and cancellated by concentric lamellae, and also a few obscure rugae.|