Tenuicorbula Olsson 1932

Genus TENUICORBULA Olsson, 1932

Tenuicorbula Olsson, 1932: type species Corbula tenuis G. B. Sowerby I, 1833, by original designation; Recent, Mazatlan to Peru.

Diagnosis. Shell thin to moderately solid, subelliptical, elongate, subequivalve, inequilateral, with a strong, sharp, and high keel between central and posterior slope; posterior slope with an acute rostrum; truncated posterior margin. Right valve with marginal groove along the free internal border where the opposite valve fits in. Sculpture similar in right and left valves with commarginal ribs. Right valve with anterior cardinal tooth and posterior deep resilial socket. Left valve with anterior cardinal socket for insertion of right cardinal tooth, and with posterior flattened chondrophore; chondrophore with a weak developed median ridge on the dorsal side, frequently delimitated by a narrow knob posteriorly. Nepioconch not distinguished.

Remarks. Tenuicorbula differs from Juliacorbula by its subelliptical outline and broader posterior slope. Both genera have a strong and sharp keel between the central and posterior slope. However, in Tenuicorbula species this keel is higher than in Juliacorbula species. Phylogenetic analyses based on conchological characters have demonstrated the similarities between Tenuicorbula and Juliacorbula (Anderson & Roopnarine 2003; Anderson et al. 2006).

Goodwin et al. (2008) did not analyze the growth of any species of Tenuicorbula. However, given the greater similarity between pre-accretion and post-accretion shells, the growth pattern in Tenuicorbula is likely to be GF1.