The perils and merits (or the Good, the Bad and the Ugly) of DNA barcoding of sponges – a controversial discussion

DNA barcodes are defined as signature sequences used to identify unknown specimens. They have been proposed as a means to quickly solve the taxonomical impediment, through an organised and highly structured effort, using the same part of the mitochondrial sub-unit I of the Cytochrome c oxidase gene to identify all species of the planet. There has been much debate about the uses and misuses of DNA for taxonomy, and the radical proposition of DNA barcodes has heated the debate. In this paper we present two contrasting views of how DNA barcodes may or may not help sponge taxonomy

O ouriço Echinometra lucunter (Echinodermata, Echinoidea) como refúgio para o gobiídeo Elacatinus figaro (Perciformes, Gobiidae)

Elacatinus are small bright colored reef fish that have the habit of cleaning fishes and invertebrates. Elacatinus figaro are often found near the sea urchin Echinometra lucunter, suggesting a possible relationship between them. The addressed questions of this study are: (1) is the territory occupied by E. figaro related to the proximity of E. lucunter?; (2) does E. figaro show a refuge preference for E. lucunter spines?; and (3) are the densities of the two organisms correlated in the studied rocky reefs? Quadrats (1.0m2) were randomly sampled in three rocky reefs in Arraial do Cabo, RJ, Brazil. Before placing each quadrat on the substrate, the distances between each of the 89 E. figaro individuals observed and their nearest urchins were registered. While placing each quadrat, the escape behavior and the chosen refuge were observed. Furthermore, the densities of E. lucunter and E. figaro in each quadrat were quantified. From all observed E. figaro, around 57% were inside the perimeter of the urchins’ spines, 21% were less than 10cm far from them, 17% were between 10cm and 20cm away from them and less than 5% were more than 20cm away from the urchins. Most of the E. figaro (around 95%) that were out of the urchins spines’ perimeter promptly moved to the nearest urchin during the quadrat location. A positive correlation was observed between the densities of E. lucunter and E. figaro, suggesting a strict association between them, probably due to the use of the spines of the sea urchin as a refuge by this goby.Elacatinus são pequenos peixes recifais de colorido brilhante que possuem hábito de limpar peixes e invertebrados. Elacatinus figaro são freqüentemente encontrados junto aos ouriços Echinometra lucunter, sugerindo uma possível relação entre eles. As questões abordadas no presente estudo são: (1) o território ocupado por E. figaro está relacionado à proximidade com E. lucunter?; (2) E. figaro mostra preferência de refúgio pelos espinhos de E. lucunter?; e (3) as densidades dos dois organismos estão correlacionadas nos recifes estudados? Quadrados (1.0m2) foram aleatoriamente amostrados em três costões rochosos em Arraial do Cabo, RJ, Brasil. Antes do posicionamento de cada quadrado no substrato, a distância entre cada um dos 89 indivíduos de E. figaro observados e o ouriço mais próximo foi registrada. Durante a colocação de cada quadrado, o comportamento de fuga e o refúgio escolhido foram observados. Além disso, foram quantificadas as densidades de E. lucunter e de E. figaro em cada quadrado. Do total de E. figaro observados, aproximadamente 57% estavam dentro do perímetro dos espinhos do ouriço, 21% estavam a menos de 10cm de distância, 17% estavam entre 10cm e 20cm de distância, e menos de 5% a mais de 20cm de distância dos ouriços. A maioria dos E. figaro (aproximadamente 95%) que não se encontravam no perímetro dos espinhos do ouriço se deslocaram rapidamente para o ouriço mais próximo durante a colocação do quadrado. Uma correlação positiva foi observada entre as densidades de E. lucunter e E. figaro, sugerindo uma associação entre eles, provavelmente devido à utilização dos espinhos do ouriço como refúgio por este gobiídeo

Molecular testing of the São Francisco River as an ecological filter for the Brazilian large-eyed stingray Hypanus marianae (Dasyatidae, Myliobatiformes)

Ecological niche modeling (ENM) provides information on the potential environmental barriers to a species that can be tested in phylogeographic studies. A previous ENM analysis of the benthic coastal stingray Hypanus marianae revealed a low suitability area for its occurrence at the São Francisco River (SFR) mouth, the fourth largest river flowing into Southwestern Atlantic. Hence, phylogeographic analyses were used to test the hypothesis of two populations: one north and another south of SFR outflow. We sampled 109 specimens in six localities throughout the species’ geographic distribution and sequenced mitochondrial (cytb) and nuclear (rag1) markers. Our analyses corroborated the existence of two groups (ΦST = 0.68, P < 0.0001) within H. marianae, partially agreeing with the ENM results. The commonest mitochondrial haplotype (H2) was shared among almost all localities, except Salvador, where all individuals shared the same and unique haplotype. This group is restricted to a shallow bay area close to SFR, as predicted by the ENM. However, its plume was not effective in isolating a continental island 55 km off the Brazilian coast. While the broad north group is protected in a few Marine Protected Areas, our results suggest that the restricted southern one deserves to be managed specifically.Fil: Costa, Tiego L. A.. Universidade Federal do Rio Grande; BrasilFil: de Figueiredo Petean, Flávia. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina. Universidade Federal do Rio Grande; BrasilFil: Berbel Filho, Waldir M.. Universidade Federal do Rio Grande; BrasilFil: Solé Cava, Antonio M.. Universidade Federal do Rio de Janeiro; BrasilFil: Mendes, Liana F.. Universidade Federal do Rio Grande do Norte; BrasilFil: Lima, Sergio M. Q.. Universidade Federal do Rio Grande; Brasi

Population genetic structure of Brazilian shrimp species (Farfantepenaeus sp., F. brasiliensis, F. paulensis and Litopenaeus schmitti: Decapoda: Penaeidae)

Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In the Southwest Atlantic, Farfantepenaeus brasiliensis, F. paulensis, F. subtilis, Farfantepenaeus sp. and Litopenaeus schmitti are among the most important commercially exploited species. Despite their high commercial value, there is little information available on the different aspects of their biology or genetics and almost no data on their stock structure. We used allozymes to estimate variability levels and population genetic structure of F. brasiliensis, F. paulensis, L. schmitti and the recently detected species Farfantepenaeus sp. along as much as 4,000 km of Brazilian coastline. No population heterogeneity was detected in F. brasiliensis or L. schmitti along the studied area. In contrast, F ST values found for Farfantepenaeus sp. and F. paulensis indicate that the populations of those two species are genetically structured, comprising different fishery stocks. The largest genetic differences in F. paulensis were found between Lagoa dos Patos (South) and the two populations from Southeast Brazil. In Farfantepenaeus sp., significant differences were detected between the population from Recife and those from Fortaleza and Ilhéus