Aim The Amazon‐Orinoco plume is the major biogeographical barrier between the Great Caribbean and the Brazilian Province. No study has so far addressed the influence of this barrier in a broad chrono‐phylogenetic context. Here, we evaluate the effects of the Amazon‐Orinoco plume barrier on the patterns of diversification of Western Atlantic reef fishes through time. Location Tropical Western Atlantic. Taxon Reef Fishes (Percomorpha). Methods We compiled DNA sequence data of 21 molecular markers from sister species/population pairs across 33 reef‐fish families in the Greater Caribbean biogeographical region and the Brazilian Province. The data included estimated divergence times between sister‐pairs based on previously published phylogenies and 94 newly proposed time‐trees. Divergence dates were compared with variations in the sedimentation discharge rate of the Amazon River and sea‐level fluctuations. To address the hypothesis that fishes with different adult sizes are affected differently by the Amazon‐Orinoco plume, we used a phylogenetic least squares regression to test the relationship between maximum total body length and divergence times between the Caribbean and Brazilian sister‐pairs. Results We identified an increase in the rates of lineage diversification between sister‐pairs of the Greater Caribbean and Brazilian Province reef fishes in the past 2.4 million years, in accordance with the period of higher sedimentation rates of the Amazon River and the more frequent sea‐level fluctuations in the Pleistocene. A strong relationship between total body length and effectiveness of the barrier through time was confirmed, with smaller species typically diverging earlier in periods when sedimentation rates of the Amazon River were significantly lower. Conclusions The strong biogeographical signal detected in this study across different lineages of reef fishes clearly indicates that the Amazon‐Orinoco plume played a significant role in the diversification of the Atlantic reef‐fish fauna. The temporal pattern of diversifications indicates a correlation between the permeability of the plume, sea‐level fluctuations, variability in the volume of the discharge and fish body size, with the barrier's influence being weaker on larger fishes.

Here we present the first phylogeny of the genus Scartella based on mitochondrial data. The analysis strongly corroborates the validity of all species of the genus and shows that Scartella cristata, a species with a disjunct distribution, is a lineage complex comprising five clades: two in Caribbean waters, another in the East Atlantic/Mediterranean and two in Brazil. Brazilian clades occur in sympatry from Rio de Janeiro to Rio Grande do Sul states (southern Brazil). One clade (BRA 1) is unique to Brazil, while the other (BRA 2) is closely related to the eastern Atlantic lineage. Possible explanations for this pattern include both natural and anthropic mechanisms.

Brazilian endemic batoid elasmobranch populations have declined dramatically in the past 40 years due to anthropic activities (e.g., overfishing). The Brazilian guitarfish, Pseudobatos horkelii, included in the IUCN red list of endangered species [Critically Endangered (CR)], has been captured as by-catch by trawling fishing boats to the edge of extinction. Despite governmental conservation initiatives, the species is still caught and commercialized along the Brazilian coast. In this study, the authors report three rare aggregation events for the Brazilian coast of P. horkelii, inside the only nearshore no-entry Brazilian marine protected area. Strategies for its protection are also discussed.

Background: A new record for Elacatinus figaro, an endangered Brazilian species, is documented for Pedra do Sal, Piauí coast. We present new data about its distribution, discussing on the limits of the Brazilian Province and commenting on the IUCN criteria for evaluation on threatening status. Results: Five specimens of E. figaro were collected about 550 km northward from its previously known boundary, overtaking the expectations around its real distribution as presented in the original description. Conclusions: Results from E. figaro range expansion and new records of species in Brazilian coast fit the hypothesis presented in Floeter et al. (J Biogeogr 35: 22-47, 2008) of a Brazilian Zoogeographic Province, also assigned by Briggs & Bowen (J Biogeogr 39: 12-30, 2012) on a review of Marine Zoogeographic Provinces.