Fishes (Actinopterygii) of the rapids and associated environments in the lower Vaupés River Basin: an undiscovered Colombian Amazon diversity.

The Vaupés River stands out as one of the few within the Amazon basin due to its numerous rapids. These riverine fast-flowing sections not only provide habitat to highly specialized fishes but also function as natural barriers hindering the movement of fish along its course. During a fish-collecting expedition in the lower Vaupés River basin in Colombia, 95 species were registered belonging to 30 families and seven orders. Despite recent inventories in the region, our comprehensive sampling efforts particularly focused on the rapids and associated rheophilic fauna, allowing us to contribute the first records of four fish species in Colombia (Mylopluslucienae Andrade, Ota, Bastos & Jégu, 2016, Tometesmakue Jégu, Santos & Jégu, 2002, also first record of the genus, Leptodoraspraelongus (Myers & Weitzman, 1956), and Eigenmanniamatintapereira Peixoto, Dutra & Wosiacki, 2015) and six presumably undescribed species (i.e., Jupiaba sp., Moenkhausia sp., Phenacogaster sp., Bunocephalus sp., Hemiancistrus sp., and Archolaemus sp.). In this study, a commented list of the ichthyofauna of these environments is presented, as well as a photographic catalog of fish species integrated into the CaVFish Project - Colombia.

Accelerated Diversification Explains the Exceptional Species Richness of Tropical Characoid Fishes.

The Neotropics harbor the most species-rich freshwater fish fauna on the planet, but the timing of that exceptional diversification remains unclear. Did the Neotropics accumulate species steadily throughout their long history, or attain their remarkable diversity recently? Biologists have long debated the relative support for these museum and cradle hypotheses, but few phylogenies of megadiverse tropical clades have included sufficient taxa to distinguish between them. We used 1288 ultraconserved element loci spanning 293 species, 211 genera, and 21 families of characoid fishes to reconstruct a new, fossil-calibrated phylogeny and infer the most likely diversification scenario for a clade that includes a third of Neotropical fish diversity. This phylogeny implies paraphyly of the traditional delimitation of Characiformes because it resolves the largely Neotropical Characoidei as the sister lineage of Siluriformes (catfishes), rather than the African Citharinodei. Time-calibrated phylogenies indicate an ancient origin of major characoid lineages and reveal a much more recent emergence of most characoid species. Diversification rate analyses infer increased speciation and decreased extinction rates during the Oligocene at around 30 Ma during a period of mega-wetland formation in the proto-Orinoco-Amazonas. Three species-rich and ecomorphologically diverse lineages (Anostomidae, Serrasalmidae, and Characidae) that originated more than 60 Ma in the Paleocene experienced particularly notable bursts of Oligocene diversification and now account collectively for 68% of the approximately 2150 species of Characoidei. In addition to paleogeographic changes, we discuss potential accelerants of diversification in these three lineages. While the Neotropics accumulated a museum of ecomorphologically diverse characoid lineages long ago, this geologically dynamic region also cradled a much more recent birth of remarkable species-level diversity. [Biodiversity; Characiformes; macroevolution; Neotropics; phylogenomics; ultraconserved elements.].

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.

Species delimitation reveals an underestimated diversity of Andean catfishes of the family Astroblepidae (Teleostei: Siluriformes)

Catfishes of the family Astroblepidae form a group composed by 82 valid species of the genus Astroblepus inhabiting high-gradient streams and rivers throughout tropical portions of the Andean Cordillera. Little has been advanced in the systematics and biodiversity of astroblepids other than an unpublished thesis, a single regional multilocus study and isolated species descriptions. Here, we examined 208 specimens of Astroblepus that apparently belong to 16 valid species from several piedmont rivers from northern Colombia to southern Peru. Using three single-locus approaches for species delimitation in combination with a species tree analysis estimated from three mitochondrial genes, we identified a total of 25 well-delimited lineages including eight valid and 17 potential undescribed species distributed in two monophyletic groups: the Central Andes Clade, which contains 14 lineages from piedmont rivers of the Peruvian Amazon, and the Northern Andes Clade with 11 lineages from trans- and cis-Andean rivers of Colombia and Ecuador, including the Orinoco, Amazon, and Magdalena-Cauca basins and Pacific coastal drainages. Results of species delimitation methods highlight several taxonomical incongruences in recently described species denoting potential synonymies.(AU)

Los bagres de la familia Astroblepidae son un grupo compuesto por 82 especies válidas del género Astroblepus que habitan quebradas y ríos de alto gradiente a través de la porcion tropical en la Cordillera de los Andes. Poco se ha avanzado en la sistemática y biodiversidad de los astroblepidos aparte de una tesis no publicada, un único estudio multilocus regional y descripciones aisladas de especies. Aquí, examinamos 208 especímenes de Astroblepus que aparentemente pertenecen a 16 especies válidas provenientes de ríos de pie de monte de la cordillera de los Andes, desde el norte de Colombia hasta el sur de Perú. Utilizando tres metodologías de delimitación de especies para un único locus en combinación con análisis de un árbol de especies a partir de tres genes mitocondriales, identificamos un total de 25 linajes bien definidos que incluyen ocho especies válidas y 17 potenciales especies no descritas distribuidas en dos grupos monofiléticos: un clado de los andes centrales, que contiene 14 especies de los ríos de pie de monte de la Amazonía peruana y un clado de los andes del norte con 11 especies de los ríos trans y cisandinos de Colombia y Ecuador, incluyendo las cuencas del Orinoco, Amazonas y Magdalena-Cauca así como drenajes costeros del Pacífico. Los resultados de los métodos de delimitación de especies destacan varias incongruencias taxonómicas en especies recientemente descritas que denotan posibles sinonimias.(AU)

Three new species of the Eigenmannia trilineata species group (Gymnotiformes: Sternopygidae) from northwestern South America

Eigenmannia is one of the more taxonomically complex genera within the Gymnotiformes. Here we adopt an integrative taxonomic approach, combining osteology, COI gene sequences, and geometric morphometrics to describe three new species belonging to the E. trilineata species group from Colombian trans-Andean region. These new species increase the number of species in the E. trilineata complex to 18 and the number of species in the genus to 25. The distribution range of the E. trilineata species group is expanded to include parts of northwestern South America and southern Central America.(AU)

Eigenmannia es uno de los géneros taxonómicamente más complejos dentro de los Gymnotiformes. En este artículo adoptamos un enfoque taxonómico integrador, que combina osteología, secuencias del gene COI y morfometría geométrica, para describir tres nuevas especies que pertenecen al grupo de especies de E. trilineata de la región transandina de Colombia. Estas nuevas especies aumentan el número de especies en el complejo E. trilineata a 18 y el número de especies en el género a 25. El rango de distribución del grupo de especies de E. trilineata se ha expandido al noroeste de Sudamérica y el sur de América Central.(AU)

Three new species of the Eigenmannia trilineata species group (Gymnotiformes: Sternopygidae) from northwestern South America

Eigenmannia is one of the more taxonomically complex genera within the Gymnotiformes. Here we adopt an integrative taxonomic approach, combining osteology, COI gene sequences, and geometric morphometrics to describe three new species belonging to the E. trilineata species group from Colombian trans-Andean region. These new species increase the number of species in the E. trilineata complex to 18 and the number of species in the genus to 25. The distribution range of the E. trilineata species group is expanded to include parts of northwestern South America and southern Central America.(AU)

Eigenmannia es uno de los géneros taxonómicamente más complejos dentro de los Gymnotiformes. En este artículo adoptamos un enfoque taxonómico integrador, que combina osteología, secuencias del gene COI y morfometría geométrica, para describir tres nuevas especies que pertenecen al grupo de especies de E. trilineata de la región transandina de Colombia. Estas nuevas especies aumentan el número de especies en el complejo E. trilineata a 18 y el número de especies en el género a 25. El rango de distribución del grupo de especies de E. trilineata se ha expandido al noroeste de Sudamérica y el sur de América Central.(AU)

Species delimitation reveals an underestimated diversity of Andean catfishes of the family Astroblepidae (Teleostei: Siluriformes)

Catfishes of the family Astroblepidae form a group composed by 82 valid species of the genus Astroblepus inhabiting high-gradient streams and rivers throughout tropical portions of the Andean Cordillera. Little has been advanced in the systematics and biodiversity of astroblepids other than an unpublished thesis, a single regional multilocus study and isolated species descriptions. Here, we examined 208 specimens of Astroblepus that apparently belong to 16 valid species from several piedmont rivers from northern Colombia to southern Peru. Using three single-locus approaches for species delimitation in combination with a species tree analysis estimated from three mitochondrial genes, we identified a total of 25 well-delimited lineages including eight valid and 17 potential undescribed species distributed in two monophyletic groups: the Central Andes Clade, which contains 14 lineages from piedmont rivers of the Peruvian Amazon, and the Northern Andes Clade with 11 lineages from trans- and cis-Andean rivers of Colombia and Ecuador, including the Orinoco, Amazon, and Magdalena-Cauca basins and Pacific coastal drainages. Results of species delimitation methods highlight several taxonomical incongruences in recently described species denoting potential synonymies.(AU)

Los bagres de la familia Astroblepidae son un grupo compuesto por 82 especies válidas del género Astroblepus que habitan quebradas y ríos de alto gradiente a través de la porcion tropical en la Cordillera de los Andes. Poco se ha avanzado en la sistemática y biodiversidad de los astroblepidos aparte de una tesis no publicada, un único estudio multilocus regional y descripciones aisladas de especies. Aquí, examinamos 208 especímenes de Astroblepus que aparentemente pertenecen a 16 especies válidas provenientes de ríos de pie de monte de la cordillera de los Andes, desde el norte de Colombia hasta el sur de Perú. Utilizando tres metodologías de delimitación de especies para un único locus en combinación con análisis de un árbol de especies a partir de tres genes mitocondriales, identificamos un total de 25 linajes bien definidos que incluyen ocho especies válidas y 17 potenciales especies no descritas distribuidas en dos grupos monofiléticos: un clado de los andes centrales, que contiene 14 especies de los ríos de pie de monte de la Amazonía peruana y un clado de los andes del norte con 11 especies de los ríos trans y cisandinos de Colombia y Ecuador, incluyendo las cuencas del Orinoco, Amazonas y Magdalena-Cauca así como drenajes costeros del Pacífico. Los resultados de los métodos de delimitación de especies destacan varias incongruencias taxonómicas en especies recientemente descritas que denotan posibles sinonimias.(AU)

Species delimitation of neotropical Characins (Stevardiinae): Implications for taxonomy of complex groups.

Accurate species delimitation is crucial for studies of phylogeny, phylogeography, ecology, conservation and biogeography. The limits of species and genera in the Characidae family are controversial due to its uncertain phylogenetic relationships, high level of morphological homoplasy and the use of ambiguous morphological characters for descriptions. Here we establish species boundaries for Bryconamericus, Hemibrycon, Knodus and Eretmobrycon (Stevardiinae: Characidae), previously diagnosed with morphology, using three different barcoding approaches (GMYC, PTP, ABGD). Results revealed that species delimitation was successful by the use of a single-gene approach and by following a workflow in the context of integrative taxonomy, making evident problems and mistakes in the cataloging of Characidae species. Hence, it was possible to infer boundaries at genus level for clusters in the trees (GMYC and PTP) and automatic partitions (ABGD) which were consistent with some of recent taxonomic changes proposed in Characidae. We found that discordance cases between methods were linked to limitations of the methods and associated to putative species cluster closely related, some historically problematic in their diagnosis and identification. Furthermore, we suggested taxonomic changes and possibly new species, revealing a high degree of hidden diversity. Finally, we propose a workflow as a fast, accurate and objective way to delimit species from mitochondrial DNA sequences and to help clarify the classification of this group.

Comparative phylogeography of trans-Andean freshwater fishes based on genome-wide nuclear and mitochondrial markers.

The Neotropical region represents one of the greatest biodiversity hot spots on earth. Despite its unparalleled biodiversity, regional comparative phylogeographic studies are still scarce, with most focusing on model clades (e.g. birds) and typically examining a handful of loci. Here, we apply a genome-wide comparative phylogeographic approach to test hypotheses of codiversification of freshwater fishes in the trans-Andean region. Using target capture methods, we examined exon data for over 1,000 loci combined with complete mitochondrial genomes to study the phylogeographic history of five primary fish species (>150 individuals) collected from eight major river basins in Northwestern South America and Lower Central America. To assess their patterns of genetic structure, we inferred genealogical concordance taking into account all major aspects of phylogeography (within loci, across multiple genes, across species and among biogeographic provinces). Based on phylogeographic concordance factors, we tested four a priori biogeographic hypotheses, finding support for three of them and uncovering a novel, unexpected pattern of codiversification. The four emerging inter-riverine patterns are as follows: (a) Tuira + Atrato, (b) Ranchería + Catatumbo, (c) Magdalena system and (d) Sinú + Atrato. These patterns are interpreted as shared responses to the complex uplifting and orogenic processes that modified or sundered watersheds, allowing codiversification and speciation over geological time. We also find evidence of cryptic speciation in one of the species examined and instances of mitochondrial introgression in others. These results help further our knowledge of the historical geographic factors shaping the outstanding biodiversity of the Neotropics.

Fishes of the Cusiana River (Meta River basin, Colombia), with an identification key to its species.

The Cusiana River sub-basin has been identified as a priority conservation area in the Orinoco region in Colombia due to its high species diversity. This study presents an updated checklist and identification key for fishes of the Cusiana River sub-basin. The checklist was assembled through direct examination of specimens deposited in the main Colombian ichthyological collections. A total of 2020 lots from 167 different localities from the Cusiana River sub-basin were examined and ranged from 153 to 2970 m in elevation. The highest number of records were from the piedmont region (1091, 54.0 %), followed by the Llanos (878, 43.5 %) and Andean (51, 2.5 %). 241 species distributed in 9 orders, 40 families, and 158 genera were found. The fish species richness observed (241), represents 77.7 % of the 314 estimated species (95 % CI=276.1-394.8). The use of databases to develop lists of fish species is not entirely reliable; therefore taxonomic verification of specimens in collections is essential. The results will facilitate comparisons with other sub-basins of the Orinoquia, which are not categorized as areas of importance for conservation in Colombia.

ResumenLa sub-cuenca del rio Cusiana ha sido designada como una de las áreas prioritarias para la conservación en la región del Orinoco en Colombia debido a su alta diversidad de especies. Este estudio presenta una lista actualizada y una clave de identificación para los peces del área. Para ello se revisaron los especímenes depositados en las principales colecciones ictiológicas colombianas. Se examinaron un total de 2020 lotes de 167 localidades diferentes de la sub-cuenca del río Cusiana, que oscilaron entre 153 y 2970 m en altitud. El mayor número de registros corresponde a la región del piedemonte (1091, 54.0%), seguida por los Llanos (878, 43.5%) y Andina (51, 2.5%). Encontramos 241 especies distribuidas en 9 órdenes, 40 familias y 158 géneros. La riqueza de especies de peces observada (241), representan el 77.7% de las 314 especies estimadas (IC 95% = 276.1-394.8). El uso de bases de datos para elaborar listas de especies de peces no es del todo fiable, por lo tanto, es esencial la verificación taxonómica de los especímenes en las colecciones. Estos resultados permitirán evaluar otras sub-cuencas de la Orinoquia, las cuales no están categorizadas como áreas de importancia para la conservación en Colombia.

Mitochondrial genomes of the South American electric knifefishes Eigenmannia humboldtii (Steindachner 1878), Eigenmannia limbata (Schreiner and Miranda Ribeiro 1903), Sternopygus aequilabiatus (Humboldt 1805) and Sternopygus macrurus (Bloch and Schneider 1801), (Gymnotiformes, Sternopygidae).

We report four mitochondrial genomes of South American electric knifefishes, derived from target capture and Illumina sequencing (HiSeq 2500 PE100). Two trans-Andean species Eigenmannia humboldtii (mitochondrial consensus genome of 25 individuals) and Sternopygus aequilabiatus (mitochondrial consensus genome of 30 individuals) from Colombia and two cis-Andean species Eigenmannia limbata from Suriname and Sternopygus macrurus from Argentina. Regarding Eigenmannia humboldtii, Eigenmannia limbata, and Sternopygus macrurus mitochondrial genomes have 13 protein-coding genes, 1 D-loop, 2 ribosomal RNAs, 22 transfer RNAs, and are 13,394 bp, 10,921 bp, and 13,013 bp in length respectively, for Sternopygus aequilabiatus mitochondrial genomes have 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and is 14,270 bp in length.

Mitochondrial genomes of the headstanders Megaleporinus muyscorum (Steindachner 1900) and Megaleporinus obtusidens (Valenciennes 1837), (Characiformes, Anostomidae).

We report two mitochondrial genomes of headstanders, derived from target capture and Illumina sequencing (HiSeq 2500 PE100). One trans-Andean species Megaleporinus muyscorum (mitochondrial consensus genome of 25 individuals) from Colombia and one cis-Andean species M. obtusidens from Argentina. Regarding M. muyscorum, mitochondrial genome has 13 protein-coding genes, 1 D-loop, 2 ribosomal RNAs, 21 transfer RNAs, and is 14,434 bp in length, for M. obtusidens mitochondrial genome has 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and is 15,546 bp in length.

Checklist of the freshwater fishes of Colombia: a Darwin Core alternative to the updating problem.

The present work is part of a process to create a Catalogue of the Freshwater Fishes of Colombia and consisted in the depuration and updating of the taxonomic and geographic components of the checklist of the freshwater fishes of Colombia. An exhaustive revision of the 1435 species recorded in 2008 was necessary to: 1. Add new species described since 2009 and species originally described from Colombia but inadvertently omitted in 2008; 2. Add new records of already described species; 3. Delete species whose presence in Colombia was not supported by voucher specimens in ichthyological collections; and 4. Revise the geographic distribution of the species listed in 2008. This process resulted in the following numbers: 1. Total number of freshwater fish species in Colombia: 1494; 2. Number of species recorded by hydrographic region - Amazon: 706, Orinoco: 663, Caribbean: 223, Magdalena-Cauca: 220, Pacific: 130; and 3. Number of endemic species: 374 (76% from the trans-Andean region). Updating the current checklist is a fundamental requirement to ensure its incorporation in the decision-making process with regard to the conservation of Colombian aquatic species and ecosystems, which are facing transformation processes as a result of activities such as mining, construction of hydroelectric plants, expansion of the agricultural frontier and subsequent deforestation, industrial and domestic pollution, development of waterways, introduction of exotic species, and climate change.

ResumenEl presente trabajo es parte de un proceso para crear un Catálogo de Peces de Agua Dulce de Colombia y consistió en la depuración y actualización de los componentes taxonómico y geográfico del listado de peces de agua dulce de Colombia. Una revisión exhaustiva de las 1435 especies registradas en 2008 fue necesaria para: 1. Adicionar las especies nuevas descritas desde 2009 y especies descritas originalmente para Colombia pero omitidas inadvertidamente en 2008; 2. Adicionar nuevos registros de especies ya descritas; 3. Eliminar especies cuya presencia en Colombia no estaba soportada por especímenes en colecciones ictiológicas; y 4. Revisar la distribución geográfica de las especies listadas en 2008. Este proceso resultó en las siguientes cifras: 1. Número total de especies de peces de agua dulce en Colombia: 1494; 2. Número de especies registradas por región hidrográfica - Amazonas: 706, Orinoco: 663, Caribe: 223, Magdalena-Cauca: 220, Pacífico: 130; y 3. Número de especies endémicas 374 (76% distribuidas en la región transandina). La actualización del presente listado es un requerimiento fundamental para asegurar su incorporación en el proceso de toma de decisiones en lo concerniente a la conservación de las especies y ecosistemas acuáticos colombianos, los cuales están enfrentando procesos de transformación, como resultado de actividades como la minería, construcción de plantas hidroeléctricas, expansión de la frontera agropecuaria y subsecuente desforestación, polución industrial y doméstica, desarrollo de hidrovías, introducción de especies exóticas y cambio climático.

Evolution of electric communication signals in the South American ghost knifefishes (Gymnotiformes: Apteronotidae): A phylogenetic comparative study using a sequence-based phylogeny.

The electric communication signals of weakly electric ghost knifefishes (Gymnotiformes: Apteronotidae) provide a valuable model system for understanding the evolution and physiology of behavior. Apteronotids produce continuous wave-type electric organ discharges (EODs) that are used for electrolocation and communication. The frequency and waveform of EODs, as well as the structure of transient EOD modulations (chirps), vary substantially across species. Understanding how these signals have evolved, however, has been hampered by the lack of a well-supported phylogeny for this family. We constructed a molecular phylogeny for the Apteronotidae by using sequence data from three genes (cytochrome c oxidase subunit 1, recombination activating gene 2, and cytochrome oxidase B) in 32 species representing 13 apteronotid genera. This phylogeny and an extensive database of apteronotid signals allowed us to examine signal evolution by using ancestral state reconstruction (ASR) and phylogenetic generalized least squares (PGLS) models. Our molecular phylogeny largely agrees with another recent sequence-based phylogeny and identified five robust apteronotid clades: (i) Sternarchorhamphus+Orthosternarchus, (ii) Adontosternarchus, (iii) Apteronotus+Parapteronotus, (iv) Sternarchorhynchus, and (v) a large clade including Porotergus, 'Apteronotus', Compsaraia, Sternarchogiton, Sternarchella, and Magosternarchus. We analyzed novel chirp recordings from two apteronotid species (Orthosternarchus tamandua and Sternarchorhynchus mormyrus), and combined data from these species with that from previously recorded species in our phylogenetic analyses. Some signal parameters in O. tamandua were plesiomorphic (e.g., low frequency EODs and chirps with little frequency modulation that nevertheless interrupt the EOD), suggesting that ultra-high frequency EODs and "big" chirps evolved after apteronotids diverged from other gymnotiforms. In contrast to previous studies, our PGLS analyses using the new phylogeny indicated the presence of phylogenetic signals in the relationships between some EOD and chirp parameters. The ASR demonstrated that most EOD and chirp parameters are evolutionarily labile and have often diversified even among closely related species.

Variation in freshwater fish assemblages along a regional elevation gradient in the northern Andes, Colombia.

Studies on elevation diversity gradients have covered a large number of taxa and regions throughout the world; however, studies of freshwater fish are scarce and restricted to examining their changes along a specific gradient. These studies have reported a monotonic decrease in species richness with increasing elevation, but ignore the high taxonomic differentiation of each headwater assemblage that may generate high ß-diversity among them. Here, we analyzed how fish assemblages vary with elevation among regional elevation bands, and how these changes are related to four environmental clines and to changes in the distribution, habitat use, and the morphology of fish species. Using a standardized field sampling technique, we assessed three different diversity and two structural assemblage measures across six regional elevation bands located in the northern Andes (Colombia). Each species was assigned to a functional group based on its body shape, habitat use, morphological, and/or behavioral adaptations. Additionally, at each sampling site, we measured four environmental variables. Our analyses showed: (1) After a monotonic decrease in species richness, we detected an increase in richness in the upper part of the gradient; (2) diversity patterns vary depending on the diversity measure used; (3) diversity patterns can be attributed to changes in species distribution and in the richness and proportions of functional groups along the regional elevation gradient; and (4) diversity patterns and changes in functional groups are highly correlated with variations in environmental variables, which also vary with elevation. These results suggest a novel pattern of variation in species richness with elevation: Species richness increases at the headwaters of the northern Andes owing to the cumulative number of endemic species there. This highlights the need for large-scale studies and has important implications for the aquatic conservation of the region.

Abundancia relativa y dieta de Grundulus bogotensis (Characiformes: Characidae) en el altiplano Cundiboyacense, Colombia / Relative abundance and diet of Grundulus bogotensis (Characiformes: Characidae) in the Cundiboyacense plateau, Colombia

Se comparó la abundancia relativa de Grundulus bogotensisentre dos cuencas y la dieta entre poblaciones de tres cuencas delaltiplano Cundiboyacense. Entre marzo y junio de 2006 se realizaronmuestreos en 10 localidades utilizando un equipo de electropesca. Laabundancia relativa de cada localidad se expresó como el número deindividuos capturado por hora en un tramo de 100m. Se utilizó untest de Kruskal-Wallis para determinar diferencias significativas en laabundancia relativa entre cuencas. Para cuantificar la dieta se utilizóel método volumétrico y para determinar el grado de similaridadentre cuencas se recurrió a tres análisis multivariados: análisis deescalonamiento multidimensional no métrico (NMDS), análisisde similaridad (ANOSIM) y análisis de porcentaje de similaridad(SIMPER). Se capturaron en total 675 individuos, empleando 600minutos de esfuerzo de captura. La abundancia de la especie en lacuenca del río Bogotá fue significativamente menor respecto a ladel río Suárez. La composición de la dieta y volumen de ítems entrecuencas fue similar. El material consumido fue de origen autóctonoy los ítems más importantes fueron los insectos inmaduros y losmicrocrustáceos. La abundancia relativa de las poblaciones de G.bogotensis en la cuenca del río Bogotá fue menor que en la cuenca delrío Suárez. La cuenca del río Suárez probablemente soporta la mayorabundancia de la especie en todo su rango de distribución y los datossugieren condiciones favorables para la sobrevivencia de la Guapuchaen el lago de Tota. El análisis de la dieta indicó una similaridad mayoral 60% en la utilización del recurso alimentar en las tres cuencas...

To compare the relativeabundance of Grundulus bogotensis in two river basinsand the diet of the populations of three basins in theCundiboyacense plateau, we sampled 10 localities usingelectrofishing equipment between March and June 2006.The relative abundance in each locality was expressedas the number of fish caught per hour on a 100mstretch; any significant differences in relative abundanceamong basins were identified via a Kruskal-Wallis test.To quantify the diet, we used the volumetric method.Similarities between the basins were determined usingthree multivariate analyzes: nonmetric multidimensionalscaling, analysis of similarity and similarity percentages.In the end, we collected a total of 675 individuals during600 minutes of capture effort. The abundance of thisspecies in the Bogotá river basin was significantly lowercompared to that of the Suárez basin. The dietarycomposition, of autochthonous origin, primarilyimmature insects and microcrustaceans and the volumeof items proved similar between the basins. In conclusion,the dietary analysis indicated a similarity exceeding 60%in the feed resource use for the three basins. The relativeabundance of populations of G. bogotensis in the Bogotáriver basin was lower than in the Suárez river basin, thelatter having, possibly, the greatest abundance of thisspecies throughout its range. The data suggests the mostfavorable conditions for the survival of the species inLake Tota...

Comparar a abundância relativa de Grundulus bogotensisentre duas bacias e a dieta entre populações de três bacias do planaltoCundiboyacense. Entre março e junho de 2006 foram realizadascoletas em 10 localidades utilizando equipamento de pesca elétrica. Aabundância relativa da espécie em cada localidade foi expressa comoo número de indivíduos capturados por hora em um trecho de 100mde extensão. Foi utilizado o teste de Kruskal-Wallis para determinardiferenças significativas na abundância relativa entre as bacias.Para quantificar a dieta foi utilizado o método volumétrico e paradeterminar o grau de similaridade entre bacias foram utilizadas trêsanálises multivariadas: análise de escalonamento multidimensionalnão métrico (NMDS), análise de similaridade (ANOSIM) e análise deporcentagem de similaridade (SIMPER). No total foram capturados675 indivíduos, empregando 600 minutos de esforço de captura. Aabundância desta espécie na bacia do rio Bogotá foi significativamentemenor que na bacia do rio Suárez. A composição da dieta e volumedos itens de alimento entre bacias foram similares. Os recursosconsumidos foram de origem autóctone e os itens mais abundantesforam insetos imaturos e microcrustáceos. A abundância relativa daspopulações de G bogotensis na bacia do rio Bogotá foi menor do quena bacia do rio Suárez. A bacia do rio Suárez provavelmente suporta amaior abundância da espécie em toda a área de distribuição e os dadossugerem condições favoráveis para a sobrevivência da Guapucha noLago de Tota. A análise da dieta indicou uma similaridade maior a60% na utilização do recurso alimentar nas três bacias...

On Apteronotus magdalenensis (Miles, 1945) (Gymnotiformes: Apteronotidae): a poorly known species endemic to the río Magdalena basin, Colombia

Based on the examination of the two available paratypes and recently collected material, we present new data and information on the electric knifefish Apteronotus magdalenensis, a species endemic to the río Magdalena-Cauca basin in Colombia. Since Miles' description in 1945, this species was not collected until recent field work at the Torrents of Honda and additional localities. We present data on the external morphology, morphometrics, pigmentation and electric organ discharges (EODs), of A. magdalenensis. We also review its distribution, ecology and conservation status.

Basados en la revisión de los dos paratipos disponibles y material recientemente colectado, presentamos nuevos datos e informaciones del pez cuchillo eléctrico Apteronotus magdalenensis, una especie endémica de la cuenca del río Magdalena-Cauca en Colombia. Desde su descripción en 1945 por Miles, esta especie no fue colectada hasta trabajo de campo llevado a cabo recientemente en los rápidos de Honda y localidades adicionales. Presentamos datos sobre la morfología externa, morformetría, pigmentación y descarga del órgano eléctrico (EOD) de A. magdalenensis. También revisamos su distribución, ecología y estatus de conservación.

On Apteronotus magdalenensis (Miles, 1945) (Gymnotiformes: Apteronotidae): a poorly known species endemic to the río Magdalena basin, Colombia

Based on the examination of the two available paratypes and recently collected material, we present new data and information on the electric knifefish Apteronotus magdalenensis, a species endemic to the río Magdalena-Cauca basin in Colombia. Since Miles' description in 1945, this species was not collected until recent field work at the Torrents of Honda and additional localities. We present data on the external morphology, morphometrics, pigmentation and electric organ discharges (EODs), of A. magdalenensis. We also review its distribution, ecology and conservation status.(AU)

Basados en la revisión de los dos paratipos disponibles y material recientemente colectado, presentamos nuevos datos e informaciones del pez cuchillo eléctrico Apteronotus magdalenensis, una especie endémica de la cuenca del río Magdalena-Cauca en Colombia. Desde su descripción en 1945 por Miles, esta especie no fue colectada hasta trabajo de campo llevado a cabo recientemente en los rápidos de Honda y localidades adicionales. Presentamos datos sobre la morfología externa, morformetría, pigmentación y descarga del órgano eléctrico (EOD) de A. magdalenensis. También revisamos su distribución, ecología y estatus de conservación.(AU)