|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Strophomenata - Strophomenida - Aegiromenidae
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. L. Benedetto 2012||Shell small, up to 5 mm wide, semielliptical in outline, with average length:width ratio of 0.64, gently concavo-convex; maximum width at the hinge line; cardinal extremities acute to nearly rectangular. Ventral valve moderately convex, with planar apsacline interarea and small convex pseudodeltidium. Dorsal valve gently concave, almost flat with hypercline dorsal interarea. Radial ornament unequally parvicostellate with 5–7 primary accentuated ribs originating at or near the umbo and one generation of less prominent ribs originating approximately at valve mid length; 4–6 fine, closely spaced parvicostellae between accentuated ribs along the anterior margin.
Ventral interior with robust teeth supported by very short dental plates, only present in adult specimens. Bilobed ventral muscle field well impressed, small, 50–60% as long as wide and extended forward approximately for 10% of the valve length; central adductor field wider than the more excavated, subtriangular diductor scars. Ventral platform (‘visceral platform’) extending to about the mid length of the valve, formed by a series of radially arranged elongate papillae and septules; isolated papillae irregularly disposed beyond the platform. A series of rounded radial grooves reflects the exterior accentuated ribs.
Dorsal interior with slender, undercut cardinal process, connecting laterally with thick widely divergent socket ridges to form an inverted V-shaped structure, with bounding minute slit-like dental sockets at their distal ends. Median septum prominent, originating anterior of alveolus, extending for two-thirds of valve length. A few short septules and isolated tubercles arranged radially on both sides of the median septum delineating an incipient, gently elevated platform confined to the medial part of the valve; septules disappear laterally, the valve floor becoming nearly smooth with only sparse small tubercles. Pallial markings not impressed.