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The high diversity and distribution of Bathygobius Bleeker, 1878 makes it an excellent group to study evolution patterns within the Atlantic. Thus, the aims of this work were to investigate the taxonomic status, geographical distribution and evolutionary history of Bathygobius in the Atlantic and to examine the genetic structure and demographic and phylogeographic history of two species widely distributed in the Atlantic, Bathygobius soporator and Bathygobius geminatus. Our results indicate that a new insular species, Bathygobius brasiliensis sp. nov., can be found in the Western Atlantic, which diverged from its sister species, Bathygobius antilliensis, around 3.03 Mya [cytochrome c oxidase I (COI) d = 0.063; cytochrome b (cyt b) d = 0.074]. There are several old mitochondrial lineages and limited gene flow among major biogeographic provinces of both B. soporator and B. geminatus (COI: overall ΦST = 0.32, P < 0.05; overall ΦST = 0.31, P < 0.05, respectively). We discuss how the Atlantic biogeographical barriers appear to have influenced the formation of the sister species of Bathygobius, and we formulate hypotheses on how the intermittent nature of biogeographical barriers, coupled with the ecological and biological traits of species and ecological and hydrological characteristics of the provinces, shaped the genetic structure and phylogeography of B. soporator and B. geminatus. [ABSTRACT FROM AUTHOR]

Trichogenes longipinnisBritski & Ortega is a narrowly distributed endemic and phenotypically variable catfish from the coastal basins of the Serra do Mar range in southeast Brazil. We examined patterns of mtDNA variation of this species in coastal basins of the Serra do Mar to determine the influences of past climatic and geomorphological processes in connection with the currently isolated basins. Allozyme data were also used to test the hypothesis that the different spotting patterns in the different areas could be the result of cryptic speciation. Regardless of body pigmentation,T. longipinnisspecimens from across the basins were found to belong to a single species, but the populations were structured in accordance with the current hydrological watersheds, in four management units across the three distinct basins of its geographic distribution. Thus, the current genetic distribution may be best explained by both marine regressions and orogeny. Based on the low levels of genetic variation and high population structure observed, we suggest thatT. longipinnisshould be classified as “vulnerable” in the Brazilian red list of threatened fauna. Furthermore, we propose that the headwaters of the Parati-Mirim River basin should be incorporated as an extension of the Bocaina National Park to protect its genetically differentiated lineages. [ABSTRACT FROM PUBLISHER]

Franciscanas are the most endangered dolphins in the Southwestern Atlantic. Due to their coastal and estuarine habits, franciscanas suffer from extensive fisheries bycatch, as well as from habitat loss and degradation. Four Franciscana Management Areas (FMA), proposed based on biology, demography, morphology and genetic data, were incorporated into management planning and in the delineation of research efforts. We re-evaluated that proposal through the analysis of control region sequences from franciscanas throughout their distribution range (N = 162), including novel sequences from the northern limit of the species and two other previously unsampled localities in Brazil. A deep evolutionary break was observed between franciscanas from the northern and southern portions of the species distribution, indicating that they must be managed as two Evolutionarily Significant Units (ESU). Furthermore, additional FMAs should be recognised to accommodate the genetic differentiation found in each ESU. These results have immediate consequences for the conservation and management of this endangered species. [ABSTRACT FROM AUTHOR]

Using a CA/CAA enriched library screening procedure, we isolated and characterised a total of seventeen polymorphic microsatellite loci for two species of Crassostrea with recognised economic importance. Eleven microsatellite loci were developed for C. rhizophorae, a Western Atlantic species for which no microsatellites were previously known. Another six loci were developed for C. gasar, a species that occurs on both sides of the South Atlantic, adding to the ten loci previously described for the species. The levels of polymorphism were estimated using 24 C. rhizophorae from Southeast Brazil (São Paulo) and 23 C. gasar individuals from North Brazil (Maranhão). The number of alleles per polymorphic locus varied from 3 to 27, and the observed and expected heterozygosities ranged between 0.174 and 0.958 and between 0.237 and 0.972 in C. rhizophorae and C. gasar, respectively. No linkage disequilibrium was found between any locus pair, and four of them exhibited deviations from Hardy–Weinberg expectations. Of the 17 loci developed, 8 cross-amplified in C. gigas and 13 in C. virginica. These markers are useful for evolution and population genetics studies of Crassostrea species and may provide fundamental data for the future cultivation of native oysters in Western Atlantic. [ABSTRACT FROM AUTHOR]

Marine sponges are an ecologically important and highly diverse component of marine benthic communities, found in all the world's oceans, at all depths. Although their commercial potential and evolutionary importance is increasingly recognized, many pivotal aspects of their basic biology remain enigmatic. Knowledge of historical biogeographic affinities and biodiversity patterns is rudimentary, and there are still few data about genetic variation among sponge populations and spatial patterns of this variation. Biodiversity analyses of tropical Australasian sponges revealed spatial trends not universally reflected in the distributions of other marine phyla within the Indo-West Pacific region. At smaller spatial scales sponges frequently form heterogeneous, spatially patchy assemblages, with some empirical evidence suggesting that environmental variables such as light and/or turbidity strongly contribute to local distributions. There are no apparent latitudinal diversity gradients at larger spatial scales but stochastic processes, such as changing current patterns, the presence or absence of major carbonate platforms and historical biogeography, may determine modern day distributions. Studies on Caribbean oceanic reefs have revealed similar patterns, only weakly correlated with environmental factors. However, several questions remain where molecular approaches promise great potential, e.g., concerning connectivity and biogeographic relationships. Studies to date have helped to reveal that sponge populations are genetically highly structured and that historical processes might play an important role in determining such structure. Increasingly sophisticated molecular tools are now being applied, with results contributing significantly to a better understanding of poriferan microevolutionary processes and molecular ecology. [ABSTRACT FROM AUTHOR]