[show abstract][hide abstract] ABSTRACT: Four Brazilian populations of Anomalocardia brasiliana were tested for mutual genetic homogeneity, using data from 123 sequences of the mtDNA cytochrome oxidase c subunit I gene. A total of 36 haplotypes were identified, those shared being H3 (Canela Island, Prainha and Acupe) and both H5 and H9 (Prainha and Acupe). Haplotype diversity values were high, except for the Camurupim population, whereas nucleotide values were low in all the populations, except for that of Acupe. Only the Prainha population showed a deviation from neutrality and the SSD test did not reject the demographic expansion hypothesis. Fst values showed that the Prainha and Acupe populations represent a single stock, whereas in both the Canela Island and Camurupim stocks, population structures are different and independent. The observed structure at Canela Island may be due to the geographic distance between this population and the remainder. The Camurupim population does not share any haplotype with the remaining populations in northeastern Brazil. The apparent isolation could be due to the rocky barrier located facing the mouth of the Mamanguape River. The results highlight the importance of wide-scale studies to identify and conserve local genetic diversity, especially where migration is restricted.
Genetics and Molecular Biology 04/2009; 32(2):423-30. · 0.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: As a result of phenotypic plasticity, the cupped oysters (Crassostrea) are difficult to identify by means of their morphology. However, molecular DNA markers are a useful means of discriminating among these species. Cupped oysters are one of the most widely cultured marine invertebrates and correct species identification is important in aquaculture. Moreover, the molecular phylogeny of the genus Crassostrea and the subfamily Crassostreinae is still not clear. In order to identify the Brazilian cupped oysters and to clarify the phylogenetic relationships of these species, we sequenced a fragment of mitochondrial DNA (16S rRNA gene) from 120 specimens collected at nine different sites distributed along the Brazilian coast. The results identified two native species of oyster:Crassostrea gasar, from the Amazon to the Parnaiba delta; and Crassostrea rhizophorae, from the northeast (Fortim) to the south of Brazil. An exotic Crassostrea species, closely related to Indo-Pacific Crassostrea, was found in one location in the north of Brazil. Crassostreashowed monophyly and the Atlantic oysters are clearly separated from the Indo-Pacific cluster.
Journal of Molluscan Studies 08/2007; 73:229-234. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: The epibenthic encrusting fauna of 2 creeks of the Caeté mangrove estuary, northern Brazil, was studied over a 13month period
using collectors fixed at 2.5 and 3.5m above the creek bottom and in which upper and lower sides of ceramic and wooden panels
were used as settlement substrates. The number of individuals of the most abundant organisms (barnacles, oysters and mussels)
settling per panel was determined each month, for each substrate type, panel orientation and height above creek bottom. The
barnacle, Fistulobalanus citerosum has a peak settlement period during the wet season whereas both peaks in the numbers of settlers of the oyster Crassostrea rhizophorae were recorded during the dry season and such discrete temporal patterns in settlement have also been observed for barnacles
and oysters in other mangroves and estuaries. In contrast to other studies, settlement of the mussel Mytella falcata was generally low during the study period and may be related to over-exploitation of stocks in the region. Overall, settler
density was usually greater on the underside of ceramic panels close to the creek bottom, similar to results of other studies
of epibenthic settlement in diverse habitats.
Wetlands Ecology and Management 01/2006; 14(1):67-78. · 1.08 Impact Factor