A new species of notodiaptomus from the ecuadorian andes (Copepoda, calanoida, diaptomidae)

Notodiaptomus cannarensis sp. n. is described from a reservoir on the Amazonian slope of the Ecuadorian Andes. The new species is unique among diaptomid calanoid copepods in the display of hypertrophied, symmetrical wing-like extensions at each side of the female composite genital somite. Furthermore, it displays a female urosome reduced to only two somites due to the incorporation of abdominal somites III and IV to the composite genital double-somite, and a male right fifth leg with the outer spine of second exopodal segment recurved and implanted proximally on margin. It differs from any other Notodiaptomus in the display of a large rectangular lamella on proximal segment of exopod of male right fifth leg. The species is currently known only from Mazar reservoir, a eutrophic water body placed above 2127 m a.s.l. on the River Paute (Cañar Province; southern Ecuador), where it is the most common crustacean in the water column. © Miguel Alonso et al

New Diaptomidae records (Crustacea: Copepoda: Calanoida: Diaptomidae) in the Neotropical region

TIn this study we present 208 new diaptomids records, including 36 species from 10 genera. They are the result of new samplings as well as of the revision of samples from previous surveys from various localities in the Neotropical Region. In an attempt to clear elucidate about the species ranges we gathered all biogeographically important data and present them here, with comments about the relevance of each record to the understanding of the distribution of the group. © 2013 Check List and Authors

Revision of Brasilibathynellocaris Jakobi, 1972 (Copepoda: Harpacticoida: Parastenocarididae) with redefinition of the genus

Members of the genus Brasilibathynellocaris Jakobi, 1972 are typical neotropical Parastenocarididae. Their geographical distribution ranges from Central America to southern Brazil, with species occurring on both sides of the Andes mountain chain. The genus can be characterized and easily identified by the following characters: leg 4 with two strong spinules on anterior margin of coxa; exopod 1 (exp-1) short and with a proximal invagination on inner corner; leg 3 with exopod inwardly curved, ending in a long forceps formed by apophysis and thumb (both with a hyaline margin). In the present work we favour revalidation of Brasilibathynellocaris, arguing for its monophyly. Pararemaneicaris Jakobi, 1972 and Paraforficatocaris Jakobi, 1972 are new junior synonyms of Brasilibathynellocaris, as a result of transfer of their respective type species: Brasilibathynellocaris cuscatlanensis (Noodt, 1962) comb. nov., and Brasilibathynellocaris paranaensis (Jakobi, 1972) comb. nov. Two monophyletic species groups, together constituting Brasilibathynellocaris, are newly proposed and diagnosed: the Brasilibathynellocaris brasilibathynellae group and the Brasilibathynellocaris salvadorensis group. Neotypes are designated for B. brasilibathynellae and B. paranaensis. comb. n ov. Redescriptions are provided for all known species of Brasilibathynellocaris. © 2010 The Linnean Society of London

A new genus of Parastenocarididae (Copepoda, Harpacticoida) from the Tocantins River basin (Goiás, Brazil), and a phylogenetic analysis of the Parastenocaridinae

Eirinicaris antonioi gen. et sp. n. (Parastenocaridinae) is described from the Brazilian rocky savannas, an ecosystem under heavy anthropogenic pressure. The subfamily is distributed worldwide, with representatives in Africa, Asia, Australia, Europe, and North America. This is the first time a non-Remaneicaris Parastenocaridinae is described from a Neotropical region indicating that Parastenocaridinae species were already present in a vast geographical area, before the split of the Gondwana. The new taxon is included within the subfamily Parastenocaridinae based on the following characters: 1) segments 5, 6, and 7 of the male antennules forming a functional unit for clasping the female; 2) segment 7 with small process at the inner margin, forming an incipient "pocket-knife" structure with segment 6; 3) last segment pointing medially when closed; 4) the endopod of female leg 3 one-segmented and spiniform, without distal seta; 5) the apophysis and terminal seta of the exopod of male leg 3 are fused; 6) the genital field is rectangular and much broader than the height in the female; 7) the group of three lateral setae I, II, and III of the furca and the dorsal seta are situated at the same level in the female; and 8) the basis of leg 1 has an inner seta. The new taxon can be distinguished from all other Parastenocaridinae genera by the unique sexually dimorphic telson and furca. In the male, the dorsal seta is inserted at the midlength of the furca and setae I, II, and III are displaced anteroventrally. A phylogenetic analysis of the subfamily Parastenocaridinae is given based on the description of the type species of each genus and available descriptions of all Parastenocaridinae species. Eirinicaris gen. n. is the sister taxon of a clade formed by Kinnecaris and Monodicaris, sharing with them the long male and female leg 5 with a long spiniform process, and with Kinnecaris, a distal pore on the spiniform process. © Paulo H.C. Corgosinho et al

The density and biomass of mesozooplankton and ichthyoplankton in the Negro and the Amazon Rivers during the rainy season: The ecological importance of the confluence boundary

The boundary zone between two different hydrological regimes is often a biologically enriched environment with distinct planktonic communities. In the center of the Amazon River basin, muddy white water of the Amazon River meets with black water of the Negro River, creating a conspicuous visible boundary spanning over 10kmalong the Amazon River. Here, we tested the hypothesis that the confluence boundary between the white and black water rivers concentrates prey and is used as a feeding habitat for consumers by investigating the density, biomass and distribution of mesozooplankton and ichthyoplankton communities across the two rivers during the rainy season. Our results show that mean mesozooplankton density (2,730 inds. m-3) and biomass (4.8 mg m-33) were higher in the black-water river compared to the white-water river (959 inds. m-33; 2.4 mg m-33); however an exceptionally high mesozooplankton density was not observed in the confluence boundary. Nonetheless we found the highest density of ichthyoplankton in the confluence boundary (9.7 inds. m-3), being up to 9-fold higher than in adjacent rivers. The confluence between white and black waters is sandwiched by both environments with low (white water) and high (black water) zooplankton concentrations and by both environments with low (white water) and high (black water) predation pressures for fish larvae, and may function as a boundary layer that offers benefits of both high prey concentrations and low predation risk. This forms a plausible explanation for the high density of ichthyoplankton in the confluence zone of black and white water rivers. © 2017 Nakajima et al