Embryonic development of the tropical bivalve Tivela mactroides (Born, 1778) (Veneridae: subfamily Meretricinae): a SEM study

Abstract : The embryonic development of Tivela mactroides, from fertilization to straight-hinge veliger D-stage larva occurs in 18 hours at 25°C. Scanning electronic observations show that morphogenetic processes result in a gastrula with two depressions 4 hours after fertilization (T0 + 4h). Two hours later, one depression, located at the animal pole, develops into an open cave, the floor of which becomes the shell field located below the lower face of the prototrochal pad. The invagination located at the vegetal pole features the blastopore. At T0 + 6h, the late gastrula has differentiated into a typical motile trochophore with a shell field synthetizing the organic part of the shell. At T0 + 8h, the shell field, located between the prototroch and the telotroch, appears as a saddle-shaped region with a wrinkled surface extending on both sides of the embryo, establishing bilateral symmetry. At T0 + 12h, the prototroch slides toward the anterior region by outgrowth of the shell material. At T0 + 18h, the prodissoconch I formation is completed and the D-stage larvae possess a calcified shell. At this stage of development, the functional velum is composed of four bands of cilia. Our observations seem to confirm the interpretation of shell differentiation proposed recently by Mouëza et al. (2006) for bivalves even if Transmission Electronic observations will be necessary to validate definitively such a model in the Meretricinae sub-family.
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Article dans une revue
Cahiers de Biologie Marine, Station Biologique, 2006, 47, pp.243-251
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https://hal.univ-antilles.fr/hal-00753022
Contributeur : Pamphile Isch <>
Soumis le : vendredi 16 novembre 2012 - 20:44:47
Dernière modification le : mercredi 21 mars 2018 - 18:57:07

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  • HAL Id : hal-00753022, version 1

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Olivier Gros, Thomas Silberfeld. Embryonic development of the tropical bivalve Tivela mactroides (Born, 1778) (Veneridae: subfamily Meretricinae): a SEM study. Cahiers de Biologie Marine, Station Biologique, 2006, 47, pp.243-251. 〈hal-00753022〉

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