|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||Age range and collections|
Bivalvia - Myalinida - Lunulacardiidae
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.
|J. Nagel-Myers and M. R. W. Amler 2007||Rounded to transversely oval in outline, subcircular ventral margin merging regularly into roundly bent anterior and posterior margins. Posterior part of hinge line straight, anterior straight to slightly convex. Umbo small, central, pointed, opisthogyrate to orthogyrate, main portion often cut off by truncation. Juvenile shell veneriform, turned anticlockwise by 90° compared to orientation of adult shell-body, not affected by truncation. Posterior truncation straight to slightly concave, cutting umbo and dorsal margin. Development, length and angle of truncation variable. Narrow, elongated groove running parallel to anterior portion of hinge-line, developing few parallel corrugations. Truncation creating posterodorsal edge, its declining portion developing irregular corrugate ornamentation more or less parallel to upper ridge of carina. Ornamentation consisting of strong and fi ne irregular radial ribs, fi ne comarginal growth lines, strong comarginal rugae. Internal characters unknown.|