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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]

The taxonomy of common dolphins (Delphinus sp.) has always been controversial, with over twenty described species since the original description of the type species of the genus (Delphinus delphis Linnaeus, 1758). Two species and four subspecies are currently accepted, but recent molecular data have challenged this view. In this study we investigated the molecular taxonomy of common dolphins through analyses of cytochrome b sequences of 297 individuals from most of their distribution. We included 37 novel sequences from the Southwestern Atlantic Ocean, a region where the short- and long-beaked morphotypes occur in sympatry, but which had not been well sampled before. Skulls of individuals from the Southwestern Atlantic were measured to test the validity of the rostral index as a diagnostic character and confirmed the presence of the two morphotypes in our genetic sample. Our genetic results show that all common dolphins in the Atlantic Ocean belong to a single species, Delphinus delphis. According to genetic data, the species Delphinus capensis is invalid. Long-beaked common dolphins from the Northeastern Pacific Ocean may constitute a different species. Our conclusions prompt the need for revision of currently accepted common dolphin species and subspecies and of Delphinus delphis distribution. [ABSTRACT FROM AUTHOR]

Management strategies for fisheries species require understanding their connectivity and population dynamics. The Brazilian slipper lobster, Scyllarides brasiliensis, is one of the most commercially important slipper lobster species in South America. We investigated, for the first time, the population genetic structure and evolutionary history of this species. Analyses of sequences of the cytochrome oxidase I gene (COI) and the control region (CR) did not reveal any significant genetic structure of S. brasiliensis (N=202) along 2700 km of the Atlantic coast (COI: ΦST = 0.0004, ΦCT = 0-0.005, P>0.05; CR: ΦST = 0.004, ΦCT = 0-0.029, P>0.05). The genetic homogeneity found suggests high levels of gene flow along the area that are possibly related to the high dispersal potential of the planktonic larvae of the species. Furthermore, the data indicate that demographic and geographical expansions of this slipper lobster population have occurred during the late and middle Pleistocene, which could be related to the fluctuating environmental conditions of that period. We investigated, for the first time, the population genetic structure and evolutionary history of Scyllarides brasiliensis. High genetic homogeneity was observed along 2700 km of south-west Atlantic coast, suggesting levels of gene flow promoted by the high dispersal potential of its larvae. This result has important implications for the conservation of the most commercially important slipper lobster species in South America. [ABSTRACT FROM AUTHOR]

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]

Molecular data have provided many insights into cetacean evolution but some unsettled issues still remain. We estimated the topology and timing of cetacean evolutionary relationships using Bayesian and maximum likelihood analyses of complete mitochondrial genomes. In order to clarify the phylogenetic placement of Sotalia and Steno within the Delphinidae, we sequenced three new delphinid mitogenomes. Our analyses support three delphinid clades: one joining Steno and Sotalia (supporting the revised subfamily Stenoninae); another placing Sousa within the Delphininae; and a third, the Globicephalinae, which includes Globicephala, Feresa, Pseudorca, Peponocephala and Grampus. We also conclude that Orcinus does not belong in the Globicephalinae, but Orcaella may be part of that subfamily. Divergence dates were estimated using the relaxed molecular clock calibrated with fossil data. We hypothesise that the timing of separation of the marine and Amazonian Sotalia species (2.3 Ma) coincided with the establishment of the modern Amazon River basin. [ABSTRACT FROM AUTHOR]

Phylogeography and population genetic studies in the Porifera have been limited by the lack of available polymorphic DNA markers. In this paper, we tested four new mitochondrial markers in nine demosponge species from a wide taxonomic range: partial sequences of the ATP synthase 6 (ATP6) and the cytochrome oxidase 2 (CO2) genes and two spacers: one located between ATP6 and CO2 and the other between the NADH dehydrogenase subunit 5 (ND5) and the small subunit ribosomal RNA (rns) genes. The new markers presented levels of nucleotide diversity up to 2.4 times higher (π = 0.015 for CO2) than those observed for the most commonly used mitochondrial marker in sponges, the cytochrome oxidase 1 gene (π = 0.006), making them suitable for alpha-level systematics, phylogeography and population genetics studies. [ABSTRACT FROM PUBLISHER]

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]

Phallusia nigra is a cosmopolitan solitary ascidian with a distinct niger-blue tunic that is considered to be an easy diagnostic feature, even in the field. The wide geographic distribution of this species may have been a result of the overconfidence of taxonomists and ecologists in the assignment of unknown specimens to this species, based on this simple diagnostic character. Indeed, there seems to be a correlation between cosmopolitanism and the presence of few, but very conspicuous diagnostic characters in benthic invertebrate species. Almost invariably, genetic studies have demonstrated that the cosmopolitanism of those species is artificial and that, rather, they are made up of groups of morphologically very similar, but genetically distinct, species. Thus, we decided to verify the specific status of Western Atlantic populations of P. nigra, from Miami (USA) to Sa˜o Paulo (southeastern Brazil) by estimating genetic variation and population structure levels along the entire range of this ascidian in the Western Atlantic. The analysis of 10 allozyme systems shows high levels of mean heterozygosity (H=0.28) so that P. nigra has genetic variation levels more related with other invertebrates than to their, phylogenetically closer, chordate relatives (that show lower levels of heterozygosity). The genetic structure of the population was relatively high (FST=0.083) for conspecific populations, but much lower than what would be expected if they belonged to different species. High levels of gene identity also indicate that the Western Atlantic population of P. nigra constitutes a single species. This result suggests an extremely high dispersal capability of the larvae of this ascidian or a relatively recent range expansion of its populations. Since this species is commonly found in harbors, the anthropogenic transport (p.e., in ballast water) may have contributed for the observed genetic homogeneity. [Copyright &y& Elsevier]

Fishing has a major impact on the biodiversity of elasmobranchs, a diverse and ancient group of fish. The illegal trade of products derived from endangered species is widespread and many times concealed by both deliberate and inadvertent mislabeling. In groups where data is sparse, such as guitarfishes, it is unknown which species are at a higher risk of extinction due to illegal trade. Brazil is currently one of the world's largest market for elasmobranch products, but it is uncertain whether the current regulatory measures are effective across all commercial sectors. Here, we applied molecular phylogenetics to identify the species sold as elasmobranchs in Rio de Janeiro. Products labeled as "shark", "ray" and "guitarfish" were sampled from fishmongers, supermarkets, restaurants and street markets (n = 221). Over 60% of the samples were derived from threatened species, reaching 90% in guitarfish and 100% in ray products. The endemic and critically endangered Pseudobatos horkelii was the only authentic guitarfish among all samples labeled as such (n = 75), all others were identified as threatened/endemic rays (Atlantoraja castelnaui , A. cyclophora) or sharks (Squatina guggenheim , S. occulta). S. guggenheim was also detected among the products labeled as "sharks" (n = 113), as were five other endangered shark species: Carcharhinus falciformis , C. signatus , Isurus oxyrhinchus , Sphyrna zygaena and S. lewini. While no mislabeling was observed in supermarkets, the prevalence was high in local trade, indicating that regulatory and awareness-raising measures must be adapted to this economically and socially important sector. [Display omitted] • Among all samples, 36% were mislabeled and 63% derived from endangered species. • Most of the endangered species we detected are endemic to Southwest Atlantic. • No guitarfish samples complied with legislation and 90% were from endangered species. • It is paramount to better regulate the local fresh-fish trade in Rio de Janeiro. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome ofCrassostrea gasarwas sequenced using the Ion Proton technology in combination with 454 Roche GS-FLX plataform data. We assembled a 17,686 bp complete circular mitochondrial genome, containing 13 protein-coding genes, a major non-coding region (MNR), two ribosomal RNA genes and 24 transfer RNA genes. Phylogenetic analysis of concatenated amino acid sequences from mitochondria showed monophyletic clades formed with high bootstrap values. This is the first complete mitochondrial sequence of an oyster from South America. Mitogenome sequence was deposited in GenBank under the accession number KR856227. [ABSTRACT FROM AUTHOR]

The land crab, Johngarthia lagostoma , occurs exclusively on Ascension Island and the Brazilian oceanic islands of Trindade, Atol das Rocas, and Fernando de Noronha. Like other gecarcinid crabs, it retains a marine planktotrophic larval phase, and as in some other gecarcinids the Megalops migrate inland into fully terrestrial habitats before moulting to the first crab instar. Due to their limited geographical distribution and their biological characteristics, the populations of J. lagostoma are especially vulnerable to environmental disturbances. The aim of this study was to assess, through analyses of mitochondrial DNA sequences, the genetic structure and diversity of J. lagostoma on the four islands where it occurs. The large differentiation observed indicates that three discrete land crab evolutionary significant units should be considered: Ascension Island, Trindade, and Atol das Rocas/Fernando de Noronha. [ABSTRACT FROM AUTHOR]

Abstract Genetic analyses of oyster seeds collected from settlement plates (in southeast Brazil Santa Catarina, N = 207) and from marsh plants (Argentina, Samborombón Bay, N = 20) revealed that most seeds did not belong to any of the oyster species recorded for the Atlantic. Phylogenetic analyses based on mitochondrial (Cytochrome c Oxidase subunit I and large ribosomal subunit) and nuclear (ribosomal Internal Transcribed Spacer 2) sequences positioned that species in the Asian oyster cluster of Crassostrea , suggesting an invasive origin and identifying the species as C. talonata , a species described for China and also recently found in Peru. The predominance of this species in cultivation settlement plates indicates that it outcompetes C. gasar , native of the South-Atlantic, making it a nuisance species for oyster cultivation. Since specimens of C. talonata have been found from the mouth of the Amazon to the coast of Argentina, it is likely that the species has a large ecological plasticity and possibly a strong invasive capacity, making it a major threat to oyster culture in the area. This is the first record of C. talonata for the Atlantic. Highlights • A small oyster has been hindering harvesting oyster seeds from the wild for cultivation in the Southwest Atlantic • Genetic analyses demonstrate that they belong to Crassostrea talonata , described here for the first time in the Atlantic • C. talonata recruits on plates less often in winter, when it is replaced by other nuisance species, of the genus Ostrea. • C. talonata is able to live under very broad environmental conditions, from the Amazon to the cold Argentinian waters. • This makes it a potential threat to oyster cultivation from tropical to temperate waters of the Atlantic. [ABSTRACT FROM AUTHOR]