An annotated checklist of freshwater copepoda (crustacea, hexanauplia) from continental Ecuador and the Galapagos archipelago

An annotated checklist of the free-living freshwater Copepoda recorded in different regions in Ecuador (including the Amazon, the Andes, the coastal region, and the Galapagos Islands) is here provided. We revised all published records, critically evaluated the validity of each taxon and provided short taxonomic and biogeographical remarks for each one. A total of 27 taxa have been reported, including species and records at the generic level only. The species and taxa identified only up to the generic level belong to five families and 14 genera. The Cyclopoida is the most diverse group with 16 records belonging to species (or identified to the generic level only) and eight genera, followed by the Harpacticoida with six species, one identification to the generic level only, and four genera, and Calanoida with four species belonging to two genera. A total of 18 taxa are recorded for the Andes. Six have been recorded in the Amazon, two are recorded for the coastal region, and six for the Galapagos. One species is shared between the Amazon and the Andes. One species is shared between the coastal region and the Amazon. Seventeen are only reported from the Andes and four are only reported from the Amazon. At the current status of the knowledge, any attempt to analyze and generalize distributional patterns of copepods in Ecuador is premature due to the scarcity of available information, and evidently there is an urgent need for more extensive field collections. A few working hypothesis for future studies are identified

Copepod diversity along the Congo River Basin: a first approach

peer reviewedThe free-living copepods of the Congo River Basin in Africa, the second largest in the world just after the Amazonas River Basin, are still insufficiently known because of problematic accessibility and complex logistics related to sampling. We analyzed samples from 82 sites obtained during expeditions in 2010 and 2013. The Congo River main channel and its main mouth tributaries (1700km; between Kisangani and Kinshasa), and the Kasai River and its main mouth tributaries (600km) were visited. A Schindler-Patallas trap was used in the open waters, with five samplings at each site. Twenty-five taxa were found, with dominance of immature forms (nauplii and copepodites). We recognized three undescribed species of Cyclopoida. The most speciose genera were: Microcyclops (five species), Mesocyclops, , and (three species each). The most frequent species were: Microcyclops varicans (27,6% of the samples) and Cryptocyclops sp. (10,6%). Few presumably cosmopolitan species were found, like pocyclops prasinus, , and Microcyclops varicans. Few diaptomid calanoids were found. Rarefaction and extrapolation curves revealed that the diversity found is about half that estimated considering just the open water species here studied. Spatially, the highest species richness was found in the main channel of the Congo River (23) compared to Kasai (20) and other tributaries (14, 9 from the Congo tributaries, 6 from the Kasai). The abundance of adult individuals was low, with an average of 2,36 individuals per sample when considering all water bodies. A distance-based redundancy analysis based on abundance and Bray Curtis dissimilarity index revealed two large groups of copepod species in the sites of the Congo main channel, plus two minor groups with mixed sites among Congo and Kasai main channels, and tributaries of both rivers, the latter being represented by small groups correlated with nitrogen forms, total phosphorus, and oxygen concentrations. Concerning the two large Congo´s channel groups of species, one was associated with water transparency, chlorophyll, and phytoplankton dominated by Dinophyceae, Chlorophyceae, Cryptophyceae, and diatoms. The other was correlated with conductivity, chlorophyll-a and Cyanophyceae. Kasai main channel sampling sites were dispersed among the four groups resulting from our analysis. Our results indicate that the copepod species in the area are separated into two large groups associated with black and white waters, with low and high primary productivity, respectively. The results showed a high copepod diversity along the Congo Basin as expected for large tropical rivers, and a low abundance for the adult copepods, as in other lotic environments. More species are expected to be discovered in this basin with the continuation of this investigation

Neotropical and Afrotropical freshwater copepods: recent advances

peer reviewedI present new perspectives and advances on the knowledge of free-living copepods in large tropical river basins. Currently, the greatest copepod diversity is known from the Palearctic region, with a surface about twice or thrice that of the Neotropical and Afrotropical areas, respectively. Interestingly, biological diversity estimators suggest a much higher and largely unexplored diversity in the two latter regions, potentially reaching or exceeding that of the Palearctic. I show trends for both regions, focused on Brazil and Congo Basins. Brazil comprises almost 40 % of the Neotropical region surface, including four rivers among the 20 largest in the world. Based on the literature review, there are 190 free-living copepod species in the country. Among the 12 hydrographic regions in Brazil, the richest are the Amazon and the Paraná basins, with the largest surface. Taxonomical studies on Brazilian copepods were predominant until 1979, yet, between 1980 and 1989 ecologically-oriented works were developed and became a main trend after 1990, representing over 80% of copepod studies after 2000. Molecular diversity and functional ecology are still poorly studied. Ecological studies with molecular-based diversity parameters, functional attributes or comprehensive spatialtemporal data of copepod species behavior and environmental variables have been used to detect effects of environmental changes both at population and community levels. Cyclopoid copepods composition and abundance changes according to the trophic level, but calanoids appear to be influenced by conductivity. The presence of cyanobacteria and phytoplankton of lower nutritional value can cause a bottom-up effect on the copepods, resulting in low functional diversity and increase of functional uniformity. Large filtering copepods can be replaced by small cyclopoids at increasing eutrophicated conditions. The Afrotropical region comprises four of the largest rivers worldwide. The most studied environments have been the great lakes of the rift valley (e.g. Tanganyika, Victoria, Kivu), the Nile River, and several places in South Africa. The Congo River, the second largest in the world, is almost entirely unknown in terms of copepod composition and ecology. Herein, I show initial data revealing the lack of knowledge of the l extant Congo copepod diversity, with a high potential for new species. Two expeditions made in 2013 and 2015 along the Congo and the Kasai River revealed 15 copepod species, but rarefaction and extrapolation diversity curves suggest the presence of at least double of this number. There are four large groups of copepods species in the Congo Basin, being the two largest separated by differences in primary productivity (white waters rivers) or microbial food web (black waters rivers). Copepods within the main channel of the Congo River seem to be less dissimilar than tributaries, thus reinforcing the effect of upstream basins, a trend observed in other large tropical river basins. Each large river has different copepod species especially for diaptomid calanoids and also for some Cyclopoida species, but just the last have shared species between Afrotropical and Neotropical regions. The river continuum and the flood pulse concepts were applied in these large tropical rivers, but both were disrupted by reservoirs. The large rivers of these tropical regions appear seem proportionally equal in copepod diversity according to this surface, and linked to their historical biogeography

Shedding light on zooplankton diversity from the Congo River Basin

peer reviewedThe Congo River Basin is the second largest in the world, and its plankton biota remains completely unknown. We studied the zooplankton diversity across 1700 km of the main channel (from the cities of Kisangani to Kinshasa) and subsequently in the mouths of the 25 largest tributaries during 2013 (N=39), and across 500 km of Kasai-Kwa River and tributaries in 2015 (N=25). We recorded 135 zooplankton species (26 for Testate Amoebae, 56 for Rotifera, 27 for Cladocera and 26 for Copepoda). At least five cladoceran and four copepod species are new. A non-metric multidimensional statistical analysis with Bray Curtis dissimilarity revealed that the zooplankton composition within Congo main channel was more similar than within the mouths of several tributaries and the Kasai-Kwa River basin. In the later, the tributaries were distinct from each other and from the main channel of Kasai River. A distance-based redundancy analysis using Bray-Curtis dissimilarity on abundance data revealed two main groups of species and limnological variables, one comprising sites with high total suspended matter, conductivity, chlorophyll, phytoplanktonabundance (white water rivers), and other with sites with high transparency and dissolved organic carbon concentration (black water rivers). Zooplankton diversity was uniform in the Congo main channel and in the Kasai-Kwa River, with low difference among sites. There was also a distinct third group, unrelated to variables. This study reveals a high diverse zooplankton community in the Congo basin, with new species and distinct community between the studied rivers, but homogeneous along each one

Trends in freshwater microcrustaceans studies in Brazil between 1990 and 2014

Abstract This study presents a review of scientiometric data about freshwater microcrustaceans (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca, Notostraca and Conchostraca) in Brazil from 1990-2014. This review is based on 179 papers published across four databases, using the following keywords in the search: microcrustaceans, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, zooplankton, reservoir, river, ponds, reservoirs, wetlands, caves, lakes, limnology, ecology, aquatic, taxonomy, systematics, morphology and biogeography. No studies were identified that addressed freshwater microcrustaceans in four (Amapá, Roraima, Alagoas and Espírito Santo) of the 27 Brazilian Federative States. Forty-five percent of the included studies were concentrated within three of the most populous states (São Paulo, Minas Gerais and Paraná), which also have a long tradition of limnological study. The included studies mostly addressed reservoirs for hydropower generation (22%), multiple environments (22%), rivers (14%) and small artificial reservoirs (11%). Pools, ponds, small lakes, wetlands and phytothelma were not widely studied. Cladocera (48%) and Copepoda (48%) were the most studied groups. No studies were identified that addressed Notostraca, Anostraca or Conchostraca. The sharp increase in the number of published freshwater studies after 2000 is likely a result of increased internet facilities and the implementation of the Scielo platform. Ecology was most frequently the study focus (~50%), followed by taxonomy. Three journals (two Brazilian and one international) accounted for the publication of 44% of the Brazilian studies on microcrustaceans. We expect the frequency of studies employing newer technologies to increase in the coming years. Based on our findings, we propose that future studies should focus on the least well-studied states and should integrate biogeography and systematic approaches. Further data on the fauna within environmental sub-types in Brazil is required