Systematics of the Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae)

Genetic evidence for a species complex within the piranha Serrasalmus maculatus (Characiformes, Serrasalmidae) from three Neotropical river basins based on mitochondrial DNA sequences

Mitochondrial molecular markers (DNA sequences of D-loop, cytochrome b and cytochrome c oxidase I) were employed to characterize populations of the piranha Serrasalmus maculatus from Upper Paraná, Upper Paraguay and Tocantins River basins. D-loop sequences of S. maculatus population from Paraná-Paraguay River basin exhibited tandem repeats of short motifs (12 base pairs) and variable numbers depending on specimens, accounting for length variation. Concatenated mitochondrial sequences suggested that S. maculatus encompasses different mitochondrial DNA lineages. Although sampling was restricted to three river basins, phylogenetic analysis clearly indicated that the species currently recognized as S. maculatus presents high genetic variability. Maximum likelihood and Bayesian analysis clustered S. maculatus populations according to their locations. However, the highest genetic differentiation was identified between populations from Paraná-Paraguay system and Tocantins River basin. Three species delimitation analyses (PTP, GMYC, and ABGD) suggested that there are at least two species among the analyzed populations. The analysis of the mitochondrial sequences evidenced genetic differentiation among populations corresponding to related, but different species, suggesting that at least S. maculatus from the Tocantins River and Paraná-Paraguay River basins are most likely different species. Therefore, S. maculatus should be considered a species complex with morphologically cryptic diversity. An integrative revision is suggested.

Molecular characterization and genetic relationships of seven piranha species of the genera Serrasalmus and Pygocentrus (Characiformes: Serrasalmidae) from Paraná-Paraguay, São Francisco and Tocantins River basins in Brazil

Genetic and phylogenetic relationships among seven piranha species of the genera Serrasalmus and Pygocentrus from the Paraná-Paraguay, São Francisco and Tocantins River basins were evaluated in the present study by partial sequences of two mitochondrial genes, Cytochrome b and Cytochrome c Oxidase I. Phylogenetic analysis of Maximum-Likelihood and Bayesian inference were performed. Results indicated, in general, greater genetic similarity between the two species of Pygocentrus (P. nattereri and P. piraya), between Serrasalmus rhombeus and S. marginatus and between S. maculatus, S. brandtii and S. eigenmanni. Pygocentrus nattereri, S. rhombeus and S. maculatus showed high intraspecific genetic variability. These species have each one, at least two different mitochondrial lineages that, currently, occur in sympatry (S. rhombeus) or in allopatry (P. nattereri and S. maculatus). Species delimitation analysis and the high values of genetic distances observed between populations of S. rhombeus and of S. maculatus indicated that each species may corresponds to a complex of cryptic species. The non-monophyletic condition of S. rhombeus and S. maculatus reinforces the hypothesis. The geographic distribution and the genetic differentiation pattern observed for the piranha species analyzed herein are discussed regarding the geological and hydrological events that occurred in the hydrographic basins.

An appraisal of the phylogenetic relationships of Hypoptopomatini cascudinhos with description of two new genera and three new species (Siluriformes: Loricariidae)

ABSTRACT The discovery of three new taxa of Hypoptotopomatini with ambiguous generic assignment prompted a reanalysis of the phylogenetic relationships of the tribe. The analysis focused on a data matrix of 56 terminals and 107 morphological characters comprising the three new taxa, most species of Hypoptopoma and Otocinclus, and all other species of the tribe. The 162 maximally parsimonious trees of 382 steps, consistency index of 0.41, and retention index of 0.83 were then summarized in a strict consensus tree. The results confirm the monophyly of the Hypoptopomatini, recover four genera as monophyletic (Acestridium, Hypoptopoma, Niobichthys, and Otocinclus), revealed Hypoptopoma and Oxyropsis to be non-monophyletic; and revealed two new genera within Hypoptopomatini. Additionally, Otocinclus was found to be sister to a group with all remaining genera of the tribe; Acestridium and Niobichthys were found to be sister to each other and that clade sister to a group formed by ((Leptotocinclus + Hypoptopoma [part]) + (Nannoxyropsis (Oxyropsis + Hypoptopoma [part]))). Based on this framework, changes to the classification and the taxonomy of the Hypoptopomatini are suggested and the new taxa are described.

GA, Ortega-Lara A, Villa-Navarro FA, Oviedo JSU, Maldonado-Ocampo JA. 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.

Biogeography of Amazonian fishes: deconstructing river basins as biogeographic units

ABSTRACT Biogeography of Amazonian fishes (2,500 species in vastly disjunct lineages) is complex and has so far been approached only partially. Here, we tackle the problem on the basis of the largest database yet on geographical distribution and phylogenetic relationships of Amazonian fishes, including all information available. Distributions of 4,095 species (both Amazonian and outgroups) and 84 phylogenetic hypotheses (comprising 549 phylogenetically-informative nodes) were compiled, qualified and plotted onto 46 areas (29 Amazonian and 17 non-Amazonian). The database was analyzed with PAE, CADE, BPA and BPA0, yielding largely congruent results and indicating that biogeographic signal is detectable on multiple dimensions of fish distribution, from single species ranges to cladistic congruence. Agreement is especially pronounced in deeper components, such as Trans-Andean, Cis-Andean, Western Amazon and Orinoco basins. Results show that all major Amazonian tributaries, as well as the Amazon basin itself, are non-monophyletic and constitute hybrid sets of heterogeneous biotic partitions. Amazonian drainages should not be assumed a priori as historically cohesive areas, contrary to widespread practice. Our hypothesis allows re-evaluation of broader issues in historical biogeography, such as the predictive power of biogeographic hypotheses, the vicariant/dispersal duality, the significance of widely distributed taxa, and the need for temporal dimension in biogeographic patterns.

An RNA-based approach to sequence the mitogenome of Hypoptopoma incognitum (Siluriformes: Loricariidae)

Hypoptopoma incognitum is a fish of the fifth most species-rich family of vertebrates and abundant in rivers from the Brazilian Amazon. Only two species of Loricariidae fish have their complete mitogenomes sequence deposited in the Genbank. An innovative RNA-based approach was used to assemble the complete mitogenome of H. incognitum with an average coverage depth of 5292×. The typical vertebrate mitochondrial features were found; 22 tRNA genes, two rRNA genes, 13 protein-coding genes, and a non-coding control region. Moreover, the use of this approach allowed the measurement of mtRNA expression levels, the punctuation pattern of editing, and the detection of heteroplasmies.

Phylogenetic relationships of the species of Acestridium Haseman, 1911 (Siluriformes: Loricariidae)

A phylogeny of the species of the loricariid genus Acestridium and relevant outgroups is presented based on a parsimony analysis of 52 unweighted and unordered morphological characters. Acestridium is diagnosed as monophyletic based on the possession of the 17 exclusive synapomorphies. Two primary trees were found, and the strict consensus among those alternative trees resulted in the following relationships: ((A. dichromum + A. triplax)(A. gymnogaster + A. scutatum + (A. discus (A. colombiensis + A. martini)))). Acestridium was found to be sister to Niobichthys with this clade subsequently the sister-group to Oxyropsis + Hypoptopoma.

A preliminary inventory of the catfishes of the lower Rio Nhamundá, Brazil (Ostariophysi, Siluriformes)

The Rio Nhamundá is a poorly-known clearwater river draining the southern Guiana Shield of Brazil. In this study we report the findings of a preliminary ichthyological survey, focusing on catfishes (Siluriformes). We identify a total of 36 species (31 genera, seven families) from the Nhamundá, including 11 species already recorded from the river. Overall, our survey results show that even rapid surveys can provide important information on Amazon fish biodiversity, suggesting potential new species, providing range extensions for nominal species, and additionally highlighting taxa in need of taxonomic revision and genetic study. As well as the traditional forms of data collected on biodiversity surveys (i.e. preserved specimen vouchers), our study also provides "new" types of data in the form of DNA barcodes and images of fishes exhibiting colouration in life, information that will be invaluable in future work addressing difficult groups. O Rio Nhamundá é um rio de água clara, pouco conhecido, que drena parte do Escudo das Guianas em território brasileiro. Nesse estudo, nós reportamos os resultados de um levantamento ictiofaunístico preliminar dessa área, tendo como foco os bagres (Siluriformes). Nós identificamos um total de 36 espécies (31 gêneros, sete famílias) provenientes de nossa coleta, e adicionamos 11 espécies já conhecidas para o rio. De maneira geral, os resultados de nossa pesquisa mostram que mesmo levantamentos rápidos podem gerar informações importantes sobre a biodiversidade de peixes amazônicos, sugerindo potenciais espécies novas, ampliando a área de distribuição de espécies, além de apontar a necessidade de revisões taxonômicas e estudos genéticos para alguns taxa. Para além das formas tradicionais de dados coletados em pesquisas de biodiversidade (i.e. espécimes preservados), nosso estudo fornece "novas" formas de dados, como DNA barcodes e imagens com o padrão de coloração dos espécimes vivos, informações essas que serão de valor inestimável para futuros estudos que abordem grupos taxonômicos difíceis.

Molecular phylogeny of the Neoplecostominae and Hypoptopomatinae (Siluriformes: Loricariidae) using multiple genes

A phylogenetic analysis is provided for representatives of more than one hundred species of the catfish family Loricariidae, including nearly all genera of the subfamilies Neoplecostominae and Hypoptopomatinae. This analysis is based on fragments of the subunit 1 of the cytochrome c oxidase gene (COI), the recombination activating genes 1 (RAG1) and 2 (RAG2), and the F-Reticulon 4 gene. We obtained an alignment of 4678 contiguous nucleotides for 136 species of 50 loricariid genera from five loricariid subfamilies, and ten outgroup species from five loricarioid families. Our results from Maximum Parsimony, Maximum Likelihood, and Bayesian analyses show the following set of interrelationships ((((Hypoptopomatinae, Neoplecostominae) Hypostominae), Loricariinae) Delturinae). However, neither Hypoptopomatinae nor Neoplecostominae were recovered as monophyletic groups. A previously hypothesized monophyly of Hypoptopomatini and Otothyrini was refuted. Furthermore, the genera Pareiorhaphis, Pareiorhina, Hisonotus and Parotocinclus were recovered as polyphyletic.