Desenvolvimento embrionário, morfometria da concha e uso de habitat do molusco entremarés Echinolittorina lineolata (d’Orbigny, 1840) (Gastropoda, Littorinidae)

Abstract

Of the marine invertebrate groups, the Mollusca phylum is the second largest group of the Animal kingdom, the Gastropoda class being the largest in number of species. Among the gastropods, those of the Littorinidae family are the most common inhabiting the majority of habitats intertidal worldwide. In Brazil, the species Echinolittorina lineolata (d' Orbigny, 1840) is distributed throughout the coast, where some studies on genetics, herbivory and ecological aspects have already been carried out, such as population density. This thesis was divided in three chapters, in search of to fill gaps on the biology and ecology of this species. In this way, chapter one had as objectives: to characterize the spawnings and the larval development of the species. Chapter two is an approach to the morphometry of the species with a focus on size in relation to different latitudes on the Brazilian coast. Chapter three analyzes the use of dead barnacles by males and females of E. lineolata, and the oxygen consumption of these animals when submitted to submerged and emergent conditions. Echinolittorina lineolata shows pelagic spawning and mixed larval development. Regarding morphometry, our results indicated that the animals present a size gradient partially consistent with the Bergmann rule, with the exception of latitude 23 °. Of the morphometric variables, the length and the width of the shell are the most representative variables that influence the animals in the different latitudes. These variables were also representative among males and females, with females being more predominant in all latitudes, with length and width of the larger shells. When using the habitat, in this case occupation of the barnacles, the individuals of E. lineolata occupied more than 50% of the dead barnacles throughout and the highest rate of oxygen consumption was when the gastropods were submerged. The use of barnacles throughout the period studied mainly by females may be related to mechanical protection and desiccation, since the animals are directly exposed to the action of the waves, being the largest one of oxygen consumption when the animals were submerged.