Six new species of Elpidium Müller, 1880 (Podocopida: Limnocytheridae) from Eastern Brazil.

Elpidium is the most common ostracod genus occurring in phytotelmata in the Neotropical region, with distributions ranging from Florida, USA in the north to Rio Grande do Sul, Brazil in the south. However, the genus remains poorly known both in terms of diversity and of the distributional pattern of its species. Here, we describe six new species of Elpidium, E. oxumae n. sp., E. cordiforme n. sp., E. picinguabaense n. sp., E. eriocaularum n. sp., E. higutiae n. sp., E. purium n. sp., all from phytotelm environments in the Brazilian Atlantic rain forest. In addition, we discuss the distributional pattern and endemicity levels of Elpidium species in the light of these new taxonomic results and argue about possible misunderstandings on the distribution of the type species E. bromeliarum.

Redescription of the type species of the genus Cypretta (Ostracoda, Crustacea), with notes on the taxonomy of the genus.

With 53 formally described species, the genus Cypretta is one of the most common freshwater ostracod genera in the world. It has a mainly circumtropical distribution. The type species, Cypretta tenuicauda (Vávra, 1895), was described from Zanzibar (Africa) in a superficial way. Therefore, the morphology and identity of this species and of the genus remained problematic until today. Here, we redescribe Cypretta tenuicauda from the original type material and discuss the morphology of the species and the diagnosis of the genus. The species is characterized by the presence of anterior marginal septa in both valves, the sub-triangular carapace shape in lateral view, the right valve overlapping the left valve, the generally wide carapace and the presence of a serrated posteroventral inner list in the right valve. In addition, both α and ß setae on the mandibular palp are long and thin, claws Ga and Gp on the caudal ramus are elongated and seta-like, while the caudal ramus itself is equally slender. The caudal ramus attachment is reduced to a simple branch. The present redescription of the type species will assist in creating order in what is now a taxonomically confused genus.

Seven new species and two new genera of Physocypria sensu latu (Crustacea, Ostracoda) from Brazilian floodplains.

We describe seven new species in two new genera of the Physocypria sensu latu clade (Cyclocypridinae) from three of the main Brazilian floodplains. Brasilocypria pea gen. et spec. nov. and Brasilocypria ricardopintoi gen. et spec. nov. occur in the Upper Paraná River floodplain and the South Matogrossense Pantanal, Claudecypria mesquitai gen. et spec. nov., Brasilocypria alisonae gen. et spec. nov. and Claudecypria rochei gen. et spec. nov. were found in the South Matogrossense Pantanal, and Brasilocypria lordi gen. et spec. nov. and Brasilocypria namiotkoi gen. et spec. nov. occur in the Amazon River floodplain. All new species here described were found as sexual populations. Generally, they have a short and suboval carapace, with the left valve overlapping the right valve on all sides, except for the dorsal side in some species. The morphology of the hemipenis and the prehensile palps, together with the shape of the valves, were the most important characters to distinguish the species. Size differences between species can be substantial. Several characters, such as the absence in all new species of the short accompanying seta of the five natatory setae on the antenna; the presence in all new species of a long seta next to the two a-setae on the first thoracopod, and the presence/absence or differences in length of specific setae on the second and third thoracopod, are relevant for the generic diagnoses. We also redefine Keysercypria Karanovic, 2011.

On a new genus and four new species of the subfamily Cyprettinae (Crustacea, Ostracoda) from Brazilian floodplains.

We describe the new genus Triangocypretta gen. nov. and four new species from Brazilian floodplains. Triangocypretta angustus gen. et spec. nov. and Triangocypretta labiata gen. et spec. nov. were described from the Amazon floodplain only, while Triangocypretta nates gen. et spec. nov. was described from Amazon, Araguaia, and Paran River floodplains. Triangocypretta hirsuta gen. et spec. nov. was recorded from all four floodplains: Amazon, Araguaia, Pantanal and Paran. The new genus is characterized by the triangular shape of the carapace in lateral view, the absence of teeth on the posteroventral inner list in the right valve and the presence of anterior marginal septa in both valves, as well as by the relatively short and thin and -setae on the mandibular palp. All populations found were asexual. Owing to the clear differences in valve anatomy and limb chaetotaxy as compared to species of Cypretta s.s., the four species were allocated to a new genus in the subfamily Cyprettinae.

On two new species of Cypricercus Sars, 1895 (Crustacea, Ostracoda) from Brazil with a discussion on the taxonomy of the genus.

We describe two new species of Cypricercus, Cypricercus alfredo sp. nov. and Cypricercus tiao sp. nov., and briefly redescribe the female of Cypricercus centrurus (Klie, 1940) from Brazilian floodplains. Both new species have the elongated carapace which is characteristic of the genus. Cypricercus alfredo sp. nov. was found as both sexual and asexual populations and has a posterior spine on the right valve and differs from the Brazilian C. centrurus by the position and the size of spine and the size and shape of the carapace. Cypricercus tiao sp. nov. was found as one asexual population only and lacks a posterior spine on the right valve. Cypricercus populations in Brazil mostly consist exclusively of asexual females, but some sexual populations and populations with mixed reproduction can also be found. This genus occurs primarily in the Southern Hemisphere, but some species can also be found in the southern part of North America and in India. We also present a re-appraisal of all species presently allocated to the genus, primarily based on original descriptions.

Taxonomic revision of Strandesia s.s. (Crustacea, Ostracoda) from four Brazilian floodplains, with the description of three new species.

The present paper is a contribution to the taxonomy of the genus Strandesia. Here, we describe three new species: S. thomazi nov. sp., S. galeati nov. sp. and S. nakatanii nov. sp. We also describe the male of Strandesia obtusata (Sars, 1901); this is the first record of sexual populations of a Brazilian Strandesia species. Nine other Strandesia species from the Amazon, Araguaia, Pantanal and Paraná river floodplains are redescribed. We also propose that Strandesia trichosa Roessler, 1990 is a synonym of Strandesia psittacea Sars, 1901. Most of the species analyzed here are endemic to the Neotropical region, with the exception of Strandesia bicuspis (Claus, 1892) G.W. Müller, which occurs also (as an alien invasive species) in the Palaearctic. This genus occurs in water bodies with a wide range of abiotic variables and in many different aquatic macrophyte species. The species analyzed here have a highly conservative soft part morphology, but an impressive variety of carapace shapes.

A database of freshwater fish species of the Amazon Basin.

The Amazon Basin is an unquestionable biodiversity hotspot, containing the highest freshwater biodiversity on earth and facing off a recent increase in anthropogenic threats. The current knowledge on the spatial distribution of the freshwater fish species is greatly deficient in this basin, preventing a comprehensive understanding of this hyper-diverse ecosystem as a whole. Filling this gap was the priority of a transnational collaborative project, i.e. the AmazonFish project - https://www.amazon-fish.com/. Relying on the outputs of this project, we provide the most complete fish species distribution records covering the whole Amazon drainage. The database, including 2,406 validated freshwater native fish species, 232,936 georeferenced records, results from an extensive survey of species distribution including 590 different sources (e.g. published articles, grey literature, online biodiversity databases and scientific collections from museums and universities worldwide) and field expeditions conducted during the project. This database, delivered at both georeferenced localities (21,500 localities) and sub-drainages grains (144 units), represents a highly valuable source of information for further studies on freshwater fish biodiversity, biogeography and conservation.

Unexpected fish diversity gradients in the Amazon basin.

Using the most comprehensive fish occurrence database, we evaluated the importance of ecological and historical drivers in diversity patterns of subdrainage basins across the Amazon system. Linear models reveal the influence of climatic conditions, habitat size and sub-basin isolation on species diversity. Unexpectedly, the species richness model also highlighted a negative upriver-downriver gradient, contrary to predictions of increasing richness at more downriver locations along fluvial gradients. This reverse gradient may be linked to the history of the Amazon drainage network, which, after isolation as western and eastern basins throughout the Miocene, only began flowing eastward 1-9 million years (Ma) ago. Our results suggest that the main center of fish diversity was located westward, with fish dispersal progressing eastward after the basins were united and the Amazon River assumed its modern course toward the Atlantic. This dispersal process seems not yet achieved, suggesting a recent formation of the current Amazon system.

On Argentodromas bellanella gen. nov., sp. nov. (Crustacea, Ostracoda) from a Stream in Northeastern Argentina (South America).

Analia Díaz and Koen Martens (2018) Argentodromas bellanella gen. nov., sp. nov. is here described from streams in the province of Misiones, in northeastern Argentina. The new genus and species belong to the family Notodromadidae. Most species in the family have morphological adaptations to a hyponeustic mode of life: their carapaces have lip-like protrusions of the valve margins near the mouth and a flat plate-like expansion of the ventral part. The new genus can be distinguished from other genera in the subfamily Notodromadinae based on valve ornamentation (surface of valves covered with polygonal elevations and many pores with setae), the ventral plate-like expansion which is set with 3-4 rows of rounded elevations and bordered with an elevated outer list, eye tubercles softly pronounced, and soft parts features (male prehensile palps moderately asymmetrical and both with elongated first segments, posterior seta of caudal ramus longer than terminal claws and anterior seta present, hemipenis with rounded outer lobe and small rounded inner lobe). For comparative purposes, valves and carapaces of species in three other Notodromadinae genera (Newnhamia, Kennethia, Notodromas) are also illustrated and re-diagnosed.

Aquatic long-distance dispersal and vicariance shape the evolution of an ostracod species complex (Crustacea) in four major Brazilian floodplains.

Cladogenesis is often driven by the interplay of dispersal and vicariance. The importance of long-distance dispersal in biogeography and speciation is increasingly recognised, but still ill-understood. Here, we study faunal interconnectivity between four large Brazilian floodplains, namely the Amazon, Araguaia, Pantanal (on Paraguay River) and Upper Paraná River floodplains, investigating a species complex of the non-marine ostracod genus Strandesia. We use DNA sequence data from the mitochondrial COI and the nuclear Elongation Factor 1 alpha genes to construct molecular phylogenies and minimum spanning networks, to identify genetic species, analyse biogeographic histories and provide preliminary age estimates of this species complex. The Strandesia species complex includes five morphological and eleven genetic species, which doubles the known diversity in this lineage. The evolutionary history of this species complex appears to comprise sequences of dispersal and vicariance events. Faunal and genetic patterns of connectivity between floodplains in some genetic species are mirrored in modern hydrological connections. This could explain why we find evidence for (aquatic) long-distance dispersal between floodplains, thousands of kilometres apart. Our phylogenetic reconstructions seem to mostly indicate recent dispersal and vicariance events, but the evolution of the present Strandesia species complex could span up to 25 Myr, which by far exceeds the age of the floodplains and the rivers in their current forms.

Checklist de ostrácodes (Crustacea, Ostracoda) dulcícolas do Pantanal Sul Mato-grossense, Brasil

ABSTRACT Nowadays there are about 2,000 species of non-marine Ostracoda described in diverse aquatic environments in the world, of which 117 species from 37 genera are known in Brazil. The present survey of ostracods of the Pantanal of the state of Mato Grosso do Sul, recorded 35 species belonging to the families Cyprididae, Candonidae, Limnocytheridae and Darwinulidae. The ostracod fauna of Brazil is still poorly known and the ostracods biodiversity from several habitats ( e.g. interstitial) remains unknown. In this sense, there is a great probability to find new records and new taxa of ostracods in the Pantanal, as well as throughout Brazil.

RESUMO Atualmente existem cerca de 2.000 espécies de Ostracoda dulcícolas descritas em diversos ambientes aquáticos do mundo, das quais cerca de 117 espécies em aproximadamente 37 gêneros são conhecidas no Brasil. O presente levantamento de ostrácodes do Pantanal Sul Mato-grossense, registrou 35 espécies pertencentes às famílias Cyprididae, Candonidae, Limnocytheridae e Darwinulidae. A fauna de ostrácodes do Brasil ainda é pouco conhecida e a biodiversidade de ostrácodes de vários habitats (por exemplo, instersticial) ainda permanecem desconhecidos. Neste sentido, existe grande probabilidade de se encontrar novos registros e novos táxons de ostrácodes no Pantanal, assim como em todo território brasileiro.

Checklist de ostrácodes (Crustacea, Ostracoda) dulcícolas do Pantanal Sul Mato-grossense, Brasil

Nowadays there are about 2,000 species of non-marine Ostracoda described in diverse aquatic environments in the world, of which 117 species from 37 genera are known in Brazil. The present survey of ostracods of the Pantanal of the state of Mato Grosso do Sul, recorded 35 species belonging to the families Cyprididae, Candonidae, Limnocytheridae and Darwinulidae. The ostracod fauna of Brazil is still poorly known and the ostracods biodiversity from several habitats ( e.g. interstitial) remains unknown. In this sense, there is a great probability to find new records and new taxa of ostracods in the Pantanal, as well as throughout Brazil.

Atualmente existem cerca de 2.000 espécies de Ostracoda dulcícolas descritas em diversos ambientes aquáticos do mundo, das quais cerca de 117 espécies em aproximadamente 37 gêneros são conhecidas no Brasil. O presente levantamento de ostrácodes do Pantanal Sul Mato-grossense, registrou 35 espécies pertencentes às famílias Cyprididae, Candonidae, Limnocytheridae e Darwinulidae. A fauna de ostrácodes do Brasil ainda é pouco conhecida e a biodiversidade de ostrácodes de vários habitats (por exemplo, instersticial) ainda permanecem desconhecidos. Neste sentido, existe grande probabilidade de se encontrar novos registros e novos táxons de ostrácodes no Pantanal, assim como em todo território brasileiro.

Checklist de ostrácodes (Crustacea, Ostracoda) dulcícolas do Pantanal Sul Mato-grossense, Brasil

Nowadays there are about 2,000 species of non-marine Ostracoda described in diverse aquatic environments in the world, of which 117 species from 37 genera are known in Brazil. The present survey of ostracods of the Pantanal of the state of Mato Grosso do Sul, recorded 35 species belonging to the families Cyprididae, Candonidae, Limnocytheridae and Darwinulidae. The ostracod fauna of Brazil is still poorly known and the ostracods biodiversity from several habitats ( e.g. interstitial) remains unknown. In this sense, there is a great probability to find new records and new taxa of ostracods in the Pantanal, as well as throughout Brazil.(AU)

Atualmente existem cerca de 2.000 espécies de Ostracoda dulcícolas descritas em diversos ambientes aquáticos do mundo, das quais cerca de 117 espécies em aproximadamente 37 gêneros são conhecidas no Brasil. O presente levantamento de ostrácodes do Pantanal Sul Mato-grossense, registrou 35 espécies pertencentes às famílias Cyprididae, Candonidae, Limnocytheridae e Darwinulidae. A fauna de ostrácodes do Brasil ainda é pouco conhecida e a biodiversidade de ostrácodes de vários habitats (por exemplo, instersticial) ainda permanecem desconhecidos. Neste sentido, existe grande probabilidade de se encontrar novos registros e novos táxons de ostrácodes no Pantanal, assim como em todo território brasileiro.(AU)

Contribution to the knowledge of the genus Vestalenula Rossetti & Martens, 1998 (Crustacea, Ostracoda, Darwinulidae), with the description of a new species, V. carinata n. sp., from the island of Florianópolis, Brazil.

The genus Vestalenula is the most species rich in the putative ancient asexual ostracod Family Darwinulidae. Several new Recent species were described from various continents, mostly based on carapace shape and structure. These species were found in a variety of aquatic and (semi-) terrestrial habitats, including springs, streams, interstitial waters, leaf litter in forests and in splash zones of waterfalls. Here, we describe V carinata n. sp. from moist leaf litter, collected from the Brazilian island of Florian6polis. The species belongs to the danielopoli-lineage within the genus because of its elongated internal tooth in the left valve and elongated external keel on the right valve. It can be distinguished from all other species in this group by its size, its L/H ratio and the relative length of the keel. The relationship of this new species to the enigmatic, putative marine species Senidarwinula terraenuxforna Choe, 1988, is discussed. An identification key to species of the genus is provided.