Taxonomia e padrões de distribuição de cascudinhos do gênero Hypoptopoma do grupo gulare (Siluriformes, Loricariidae) na Bacia Amazônica

The genus Hypoptopoma comprises eight valid species, being a group of the subfamily Hypoptopomatinae (Loricariidae), which is widely distributed in South America, from Venezuela to Argentina. Within the genus, the Hypoptopoma gulare group is composed by species with long pectoral spine and only two rows of complete abdominal plates, which are: H. gulare, H. joberti and H. steindachneri from Amazon, and H. inexspectatum from Paraná-Paraguay. Nevertheless, the specifics and geographical boundaries of these species remain unclear. Thus, this work aimed to revise the taxonomic composition of this group in the Amazon basin. Morphometric analyses (using measurements and counts) of the preserved specimens from ichthyological collections identified five morphotypes. One was associated to the nominal species, H. gulare, and the others were considered undescribed: Hypoptopoma sp. n. “Urucu”, Hypoptopoma sp. n. “Trombetas”, Hypoptopoma sp. n. “anão” e H. sp. n. “Marajó. In this revision it is suggested that H. steindachneri and H. joberti are junior synonymies of H. gulare. The geographic distribution of this species is expanded from Marañon/Ucayali to the Madeira Basin. The pattern of morphological variation found in H. gulare suggests the existence of a morphological (or phenotypical) cline, with a gradient of variation from upstream to downstream.O gênero Hypoptopoma compreende oito espécies válidas, constituindo um grupo da subfamília Hypoptopomatinae (Loricariidae) amplamente distribuído na América do Sul, desde a Venezuela até a Argentina. Dentro do gênero, o grupo gulare, composto por espécies com espinho peitoral longo e apenas duas séries completas de placas abdominais, possui três representantes amazônicos, H. gulare, H. joberti e H. steindachneri, e uma espécie da bacia Paraná-Paraguai, H. inexpectatum. No entanto, os limites específicos e geográficos dessas espécies não estão bem compreendidos. Dessa forma, este trabalho objetivou revisar a composição taxonômica desse grupo na bacia amazônica. Após registro de informações morfométricas e merísticas de exemplares depositados em coleções ictiológicas, foram diagnosticados cinco morfotipos, dos quais um foi associado à espécie nominal, H. gulare, e os demais a espécies não descritas: Hypoptopoma sp. n. “Urucu”, Hypoptopoma sp. n. “Trombetas”, Hypoptopoma sp. n. “anão” e Hypoptopoma sp. n. “Marajó). Nesta revisão sugere-se que H. steindachneri e H. joberti sejam sinônimos juniores de H. gulare, e esta espécie tem sua distribuição estendida desde o Marañon/Ucayali até a bacia do rio Madeira. O padrão de variação morfológica (ou fenotípica) encontrado para H. gulare indica a presença de clina morfológica, cujo gradiente se apresenta no sentido montante-jusante da bacia

Multilocus phylogeny and historical biogeography of Hypostomus shed light on the processes of fish diversification in La Plata Basin

Distribution history of the widespread Neotropical genus Hypostomus was studied to shed light on the processes that shaped species diversity. We inferred a calibrated phylogeny, ancestral habitat preference, ancestral areas distribution, and the history of dispersal and vicariance events of this genus. The phylogenetic and distribution analyses indicate that Hypostomus species inhabiting La Plata Basin do not form a monophyletic clade, suggesting that several unrelated ancestral species colonized this basin in the Miocene. Dispersal to other rivers of La Plata Basin started about 8 Mya, followed by habitat shifts and an increased rate of cladogenesis. Amazonian Hypostomus species colonized La Plata Basin several times in the Middle Miocene, probably via the Upper Paraná and the Paraguay rivers that acted as dispersal corridors. During the Miocene, La Plata Basin experienced marine incursions, and geomorphological and climatic changes that reconfigured its drainage pattern, driving dispersal and diversification of Hypostomus. The Miocene marine incursion was a strong barrier and its retraction triggered Hypostomus dispersal, increased speciation rate and ecological diversification. The timing of hydrogeological changes in La Plata Basin coincides well with Hypostomus cladogenetic events, indicating that the history of this basin has acted on the diversification of its biota.Fil: Cardoso, Yamila Paula. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Sistemática y Biología Evolutiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Jardim de Queiroz, Luiz. Universidad de Ginebra; SuizaFil: Bahechar, Ilham A.. Universidad de Ginebra; SuizaFil: Posadas, Paula Elena. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Sistemática y Biología Evolutiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Montoya Burgos, Juan Ignacio. Universidad de Ginebra; Suiz

A coleção ictiológica da Universidade Federal de Rondônia: Sua importância para o conhecimento da diversidade de peixes da Amazônia

Biological collections preserve the biodiversity of a nation. The fish collection of the Universidade Federal de Rondônia, recently established, contains about 41% of freshwater fish species known to occur in Brazil, and 24% of South America. The biological material is distributed into 1,067 species, 21,963 lots and 149,192 specimens, gathered during five years of work. From this collection, 99% of the lots have georeferenced location, and 94% of the species were sampled in the Madeira River basin, the largest tributary in flow, drainage area and sediment discharge of the Amazonas River basin. Among the 1,008 species collected in the Madeira River basin, 80% were reviewed by Brazilian, North American and French experts, and represents the highest richness among tributaries of the Amazonas River and other rivers worldwide. Fish collection from the Madeira River basin deposited in the ichthyological collection of the Universidade Federal de Rondônia accounts for about 75% of the lots and specimens of fish from that basin available for study in collections worldwide. © 2015 Eduem - Editora da Universidade Estadual de Maringa. All rights reserved

Fishes of Cuniã Lake, Madeira River Basin, Brazil

This study presents an inventory of the ichthyofauna of Cuniã Lake, situated in the floodplain of the Madeira River in Rondônia State, Brazil. A total of 11,949 specimens representing eight orders, 34 families, and 189 species were sampled with gill, seine, and hand nets during the dry and wet seasons between 2008 and 2012. Most of the species recorded in Cuniã Lake are commonly found in other locations in the central Amazonian floodplains, although some are rare in collections (e.g. Acestrorhynchus minimus, Triportheus culter, Oxybrycon parvulus, Tyttocharax madeirae, Trachycorystes trachycorystes and Scorpiodoras lyophisus) or represent new distributional records. © 2013 Check List and Authors

Processes that drive the population structuring of Jenynsia lineata (Cyprinidontiformes, Anablepidae) in the La Plata Basin

1. The distribution of genetic diversity across a species distribution range is rarely homogeneous, as the genetic structure among populations is related to the degree of isolation among them, such as isolation by distance, isolation by barrier, and isolation by environment. 2. Jenynsia lineata is a small viviparous fish that inhabits a wide range of habitats in South America. To decipher the isolation processes that drive population structuring in J. lineata, we analyzed 221 sequences of the mitochondrial cytochrome c oxidase I gene (COI), from 19 localities. Then, we examined the influence of the three most common types of isolation in order to explain the genetic variation found in this species. 3. Our results revealed a marked structuration, with three groups: (a) La Plata/ Desaguadero Rivers (sampling sites across Argentina, Uruguay, and Southern Brazil), (b) Central Argentina, and (c) Northern Argentina. A distance-based redundancy analysis, including the explanatory variables geographical distances, altitude, latitude, and basin, was able to explain up to 65% of the genetic structure. A variance partitioning analysis showed that the two most important variables underlying the structuration in J. lineata were altitude (isolation by environment) and type of basin (isolation by barrier). 4. Our results show that in this species, the processes of population diversification are complex and are not limited to a single mechanism. The processes that play a prominent role in this study could explain the high rate of diversity that characterizes freshwater fish species. And these processes in turn are the basis for possible speciation events.Instituto de Limnología "Dr. Raúl A. Ringuelet"Laboratorio de Sistemática y Biología Evolutiv

Climate, immigration and speciation shape terrestrial and aquatic biodiversity in the European Alps.

Quaternary climate fluctuations can affect speciation in regional biodiversity assembly in two non-mutually exclusive ways: a glacial species pump, where isolation in glacial refugia accelerates allopatric speciation, and adaptive radiation in underused adaptive zones during ice-free periods. We detected biogeographic and genetic signatures associated with both mechanisms in the assembly of the biota of the European Alps. Age distributions of endemic and widespread species within aquatic and terrestrial taxa (amphipods, fishes, amphibians, butterflies and flowering plants) revealed that endemic fish evolved only in lakes, are highly sympatric, and mainly of Holocene age, consistent with adaptive radiation. Endemic amphipods are ancient, suggesting preglacial radiation with limited range expansion and local Pleistocene survival, perhaps facilitated by a groundwater-dwelling lifestyle. Terrestrial endemics are mostly of Pleistocene age and are thus more consistent with the glacial species pump. The lack of evidence for Holocene adaptive radiation in the terrestrial biome is consistent with faster recolonization through range expansion of these taxa after glacial retreats. More stable and less seasonal ecological conditions in lakes during the Holocene may also have contributed to Holocene speciation in lakes. The high proportion of young, endemic species makes the Alpine biota vulnerable to climate change, but the mechanisms and consequences of species loss will likely differ between biomes because of their distinct evolutionary histories

Linking human impacts to community processes in terrestrial and freshwater ecosystems.

Human impacts such as habitat loss, climate change and biological invasions are radically altering biodiversity, with greater effects projected into the future. Evidence suggests human impacts may differ substantially between terrestrial and freshwater ecosystems, but the reasons for these differences are poorly understood. We propose an integrative approach to explain these differences by linking impacts to four fundamental processes that structure communities: dispersal, speciation, species-level selection and ecological drift. Our goal is to provide process-based insights into why human impacts, and responses to impacts, may differ across ecosystem types using a mechanistic, eco-evolutionary comparative framework. To enable these insights, we review and synthesise (i) how the four processes influence diversity and dynamics in terrestrial versus freshwater communities, specifically whether the relative importance of each process differs among ecosystems, and (ii) the pathways by which human impacts can produce divergent responses across ecosystems, due to differences in the strength of processes among ecosystems we identify. Finally, we highlight research gaps and next steps, and discuss how this approach can provide new insights for conservation. By focusing on the processes that shape diversity in communities, we aim to mechanistically link human impacts to ongoing and future changes in ecosystems