Descriçao da ovicápsula de Turbinella laevigata Anton (Mollusca, Gastropoda)

MATTHEWS-CASCON, H, ROCHA-BARREIRA, C., BIGATTI, G. Y PENCHASZADEH

Rio de Janeiro, Brasil

Congreso; 1er Congresso Brasileiro de Biología Marinha.; 2006

Universidade Federal Fluminense.

ABSTRACT: Turbinella laevigata Anton, 1839 is found in the intertidal zone up to 40 m depth, being endemic of Brazil where it occurs from the state of Amapá to the state of Espirito Santo. T.laevigata has a large shell measuring up to 180 mm in length. The teleoconch has eight whorls and the protoconch is mamiliform with three smooth whorls with deep sutures and the separation of the teleoconch well defined. The objective of this study was to describe the egg masses of Turbinella laevigata.  Fifteen egg masses collected in the Olho d’Água Beach, City of Icapuí (4º 39’S, 37º 27’W), and   Fleixeiras Beach, City of Trairí (3º 22’S, 39º 25’W), both in the  state of  Ceará, Northeast Brazil, were studied. The spawns of T.laevigata were composed in average by 15 +/- 1.4 SD egg capsules and had in average 63 +/- 6.4 SD mm of length with 41 +/- 2.5 SD mm of width.  Each egg capsule measured in average 32.3 +/- 6.4 SD mm of diameter and 0.4 +/- 0.09 SD mm of thickness.  These spawns were attached to seaweeds for one of the extremities. All the egg capsules of the spawn of T.laevigata were fixed by the basal membrane, the extremity was modified to hold itself to the substratum. Each egg capsule had a convex and a concave surface, and plaited edges, that drew out until the basal membrane, to which they joined forming a medial ridge.  In some capsules, it was found a disruption in the center, where there is fewer eggs, corresponding probably to the escape opening. The egg capsules in the two extremities of the spawn were smaller than the others, and the terminal capsule was always empty.  The number of eggs presented in each capsule was, in average, 240.  This species apparently produces a great amount of nurse eggs.  The early juveniles measured in mean 6.4 +/- 0.7 SD mm of length and the presented a  protoconch with 3 whorls. Descriptors: Reproduction, Mollusca, Turbinellidae