Reproductive traits of Crepidula aculeata (Gastropoda: Calyptraeidae) from Argentina.

MAXIMILIANO CLEDÓN; EMILIANO OCAMPO; NAHUEL FARIAS; PABLO PENCHASZADEH

Antwerp, Belgium

Congreso; World Congress of Malacology; 2007

UNITAS MALACOLOGICA

Reproductive traits for Argentina are presented here. Males present a conspicuous penis when shell length (SL) is between 4.9 and 15.1 mm. Sexchange can start at 8 mm in SL. Then penis undergoes resorption as well as testis. Simultaneously female reproductive system develops. The smallest brooding female found was 16.4 mm in SL. The reproductive season occurs in spring-summer but depends on the latitude. In Mar del Plata (38°02’22S, 57°31’38W) it extends from September to April, while in San Antonio Oeste (40°43’38S, 64°55’57W) from end of October until April. No latitudinal differences were found between broods of both latitudes. Broods contained 9 to 21 triangular egg capsules, which is more than in Venezuela. Egg capsules are 2.84 to 5.36 mm in width. Egg diameter was 230 20 µm, which is the half of the diameter reported for venezuelan C aculeata. There were 217 to 664 embryos starting development synchronously, more than the double than in the venezuelan population. Between 6 and 21 reach juvenile size feeding from each other, similar to venezuelan population. The hatchlings were 850 to 1050 µm in SL, which is a similar size to the reported in Venezuela. The number and diameter of eggs supports that the argentinean population is in fact a different species than the caribbean C aculeata. Results are compared with other species of Crepidula with direct development show no coincidence.