Size at first maturity, oocyte envelopes and external morphology of the sperm in three species of Lucinidae (Mollusca: Bivalvia) from Florida Keys, USA.

G. BIGATTI, M. PEHARDA AND J. TAYLOR

MALACOLOGIA

Año: 2004 vol. 46 p. 417 - 426

0076-2997

Gonads in the tropical lucinid bivalves Ctena orbiculata, Codakia orbicularis and Lucina pensylvanica are located in the cephalopodial mass, above the foot and behind the gills.  Age estimates for Lucina pensylvanica suggest that individuals less than one year old are immature, as also in C. orbicularis, and that both males and females mature at two years. For Ctena orbiculata, we have no age data , but we consider that this species may also have early development. In July 2002 when water temperatures were high, mature individuals of all three species were spawning or in resorption and presented oocyte envelopes. Parasites were found in the digestive diverticula of C. orbiculata and L. pensylvanica. External ultrastructure of the spermatozoon shows differences between the three species. Codakia orbicularis and  L. pensylvanica have a long-headed spermatozoa, while C. orbiculata has a middle size head. Codakia  orbicularis possesses an undulating membrane in the tail, lacking in the other two species