Molecular phylogenetics of Neotropical detritivorous fishes of the family Curimatidae (Teleostei: Characiformes).

Curimatidae, the fourth largest family of detritivorous Neotropical characiform fishes, encompasses eight extant genera and over 110 species dwelling in diverse freshwater habitats from Costa Rica to Argentina. Extensive phylogenetic analyses of soft anatomy and osteology provided evidence for intergeneric and most interspecific relationships, and formed the basis of curimatid taxonomy for nearly 40 years. However, that morphological phylogeny demonstrated incomplete phylogenetic resolution at various scales and has never been tested with extensive molecular data. Herein, we infer molecular phylogenies spanning ∼70% of the known species diversity using three nuclear and three mitochondrial loci. Topologies from concatenated likelihood and Bayesian analyses and coalescent Bayesian species trees agree broadly with each other, and with the prior morphological hypothesis in many, but not all respects. All molecular analyses support the monophyly of Curimatidae and of six of its constituent genera, and agree on the placement of Curimatopsis as sister to all other curimatids. DNA-based intergeneric relationships differ substantially from prior morphological hypotheses by placing Curimata sister to Potamorhina and Psectrogaster sister to Pseudocurimata, rather than in a ladderized arrangement. Our results also resolve a major uncertainty in the morphological tree by revealing Cyphocharax, a genus for which no anatomical synapomorphy has ever been proposed, as a paraphyletic assemblage containing a monophyletic Steindachnerina and a polyphyletic Curimatella. Overall, the phylogeny expands substantially our understanding of the morphology, phylogenetics and evolution of the Curimatidae, and will guide future intrageneric studies by improving precision in the choice of comparative taxa.

Trophic evolution in African citharinoid fishes (Teleostei: Characiformes) and the origin of intraordinal pterygophagy.

The African freshwater suborder Citharinoidei (Characiformes) includes 110 species that exhibit a diversity of feeding modes comparable to those characteristic of more speciose groups such its sister, the Characoidei (2000+ species) or the distantly related Cichlidae (1600+ species). Feeding habits of the Citharinoidei range from generalist omnivores to highly specialized feeding modes including ectoparasitic fin-eating, i.e. pterygophagy. We examine diet preference evolution in the Citharinoidei using newly inferred multi-gene-based hypotheses of phylogenetic relationships for representatives of 12 of the 15 genera in the suborder. Ancestral character state reconstructions onto our best tree indicate that the three most-generalist diets - pelophage/planktivore, omnivore and invertivore - are also the most primitive conditions within the Citharinoidei. The feeding mode of the most recent common ancestor of the Citharinoidei was characterized by high uncertainty. The more specialized feeding habits - herbivory, piscivory and pterygophagy - originated later in the Citharinoidei, likely from invertivore ancestors and possibly across a short time period. Highly specialized fin eaters (Belonophago, Phago and Eugnatichthys) share a common origin along with a strict piscivore (Mesoborus) and an invertivore (Microstomatichthyoborus). The largely piscivorous, but facultative fin eater, Ichthyborus is not exclusively related to them. Our results demonstrate that overall diet preference transitions in the Citharinoidei were rare events with very few reversals or parallelisms, and that evolutionary shifts in trophic ecology have not played a major role in intraordinal diversification. This situation contrasts with other groups in which dietary transitions have played key roles in species diversification.

Herbivory Promotes Dental Disparification and Macroevolutionary Dynamics in Grunters (Teleostei: Terapontidae), a Freshwater Adaptive Radiation.

Trophic shifts into new adaptive zones have played major (although often conflicting) roles in reshaping the evolutionary trajectories of many lineages. We analyze data on diet, tooth, and oral morphology and relate these traits to phenotypic disparification and lineage diversification rates across the ecologically diverse Terapontidae, a family of Australasian fishes. In contrast to carnivores and most omnivores, which have retained relatively simple, ancestral caniniform tooth shapes, herbivorous terapontids appear to have evolved a variety of novel tooth shapes at significantly faster rates to meet the demands of plant-based diets. The evolution of herbivory prompted major disparification, significantly expanding the terapontid adaptive phenotypic continuum into an entirely novel functional morphospace. There was minimal support for our hypothesis of faster overall rates of integrated tooth shape, spacing, and jaw biomechanical evolution in herbivorous terapontids in their entirety, compared with other trophic strategies. There was, however, considerable support for accelerated disparification within a diverse freshwater clade containing a range of specialized freshwater herbivores. While the evolutionary transition to herbivorous diets has played a central role in terapontid phenotypic diversification by pushing herbivores toward novel fitness peaks, there was little support for herbivory driving significantly higher lineage diversification compared with background rates across the family.

Molecular phylogenetics of the Neotropical fish family Prochilodontidae (Teleostei: Characiformes).

Migratory detritivores of the characiform family Prochilodontidae occur throughout the freshwaters of much of South America. Prochilodontids often form massive populations and many species achieve substantial body sizes; a combination that makes them one of the most commercially important fish groups on the continent. Their economic significance notwithstanding, prochilodontids have never been the subject of a comprehensive molecular phylogenetic analysis. Using three mitochondrial and three nuclear loci spanning all prochilodontid species, we generated a novel phylogenetic hypothesis for the family. Our results strongly support monophyly of the family and the three included genera. A novel, highly supported placement of Ichthyoelephas sister to the clade containing Prochilodus and Semaprochilodus diverges from a previous morphological hypothesis. Most previously hypothesized interspecific relationships are corroborated and some longstanding polytomies within Prochilodus and Semaprochilodus are resolved. The morphologically similar P. brevis, P. lacustris, P. nigricans and P. rubrotaeniatus are embedded within what is herein designated as the P. nigricans group. Species limits and distributions of these species are problematic and the group clearly merits taxonomic revision.

A morphological supermatrix-based phylogeny for the Neotropical fish superfamily Anostomoidea (Ostariophysi: Characiformes): phylogeny, missing data and homoplasy.

Although 11 studies have addressed the systematics of the four families and 281 fish species of the ecomorphologically diverse Anostomoidea, none has proposed a global hypothesis of relationships. We synthesized these studies to yield a supermatrix with 463 morphological characters among 174 ingroup species, and inferred phylogeny with parsimony and Bayesian optimization. We evaluated the applicability of the supermatrix approach to morphological datasets, tested its sensitivity to missing data, determined the impact of homoplastic characters on phylogenetic resolution, and determined the distribution of homologies and homoplasies on the topology. Despite more than 60% missing data, analyses supported the monophyly of all families, and phylogenetic structure degraded only with inclusion of species with high percentages of missing data and in analyses limited to homoplasies. The latter differs modestly from the full matrix indicating phylogenetic signal in homoplastic characters. Character distributions differ across the phylogeny, with a greater prevalence of homologies at deeper nodes and homoplasies nearer the tips than expected by chance. This may suggest early diversification into distinct bauplans with subsequent diversification of faster evolving character systems. The morphological supermatrix approach is powerful and allows integration of classical data with modern methods to examine the evolution of multiple character systems.

The first molecular phylogeny of Chilodontidae (Teleostei: Ostariophysi: Characiformes) reveals cryptic biodiversity and taxonomic uncertainty.

Chilodontidae is a small family of eight described characiform species popularly known as headstanders. These small to moderately sized fishes are well known to aquarists, who prize their striking spotted pigmentation and unusual behaviors, and to systematists, who have revised both chilodontid genera in recent memory and studied their phylogenetic relationships using a comprehensive morphological dataset. However, no molecular phylogeny for the family has ever been proposed. Here, we reconstruct phylogenetic relationships for all eight known chilodontid species using three mitochondrial and two nuclear loci. Results largely agree with the previous morphological hypothesis, and confirm the monophyly of the family as well as its included genera, Caenotropus and Chilodus. The molecular topology differs slightly from the morphological hypothesis by placing Caenotropus maculosus rather than C. mestomorgmatos as the sister to the remaining three congeners, and by reconstructing the Curimatidae as the closest outgroup family, rather than the Anostomidae. However, the topologies supported by the morphological data were only slightly less likely and could not be rejected via Shimodaira-Hasegawa tests. Within Chilodus, two described species with distinctive pigmentation (C. fritillus and C. zunevei) appear embedded within the broad distributed C. punctatus clade, suggesting the presence of cryptic taxa with polymorphic pigmentation within the present concept of C. punctatus. Future work should combine morphological and molecular data to revisit the taxonomy and systematics of Chilodus and determine species limits within the C. punctatus-group sensu lato.

Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling.

BACKGROUND: With nearly 1,100 species, the fish family Characidae represents more than half of the species of Characiformes, and is a key component of Neotropical freshwater ecosystems. The composition, phylogeny, and classification of Characidae is currently uncertain, despite significant efforts based on analysis of morphological and molecular data. No consensus about the monophyly of this group or its position within the order Characiformes has been reached, challenged by the fact that many key studies to date have non-overlapping taxonomic representation and focus only on subsets of this diversity. RESULTS: In the present study we propose a new definition of the family Characidae and a hypothesis of relationships for the Characiformes based on phylogenetic analysis of DNA sequences of two mitochondrial and three nuclear genes (4,680 base pairs). The sequences were obtained from 211 samples representing 166 genera distributed among all 18 recognized families in the order Characiformes, all 14 recognized subfamilies in the Characidae, plus 56 of the genera so far considered incertae sedis in the Characidae. The phylogeny obtained is robust, with most lineages significantly supported by posterior probabilities in Bayesian analysis, and high bootstrap values from maximum likelihood and parsimony analyses. CONCLUSION: A monophyletic assemblage strongly supported in all our phylogenetic analysis is herein defined as the Characidae and includes the characiform species lacking a supraorbital bone and with a derived position of the emergence of the hyoid artery from the anterior ceratohyal. To recognize this and several other monophyletic groups within characiforms we propose changes in the limits of several families to facilitate future studies in the Characiformes and particularly the Characidae. This work presents a new phylogenetic framework for a speciose and morphologically diverse group of freshwater fishes of significant ecological and evolutionary importance across the Neotropics and portions of Africa.

Phylogenomic incongruence, hypothesis testing, and taxonomic sampling: The monophyly of characiform fishes.

Phylogenomic studies using genome-wide datasets are quickly becoming the state of the art for systematics and comparative studies, but in many cases, they result in strongly supported incongruent results. The extent to which this conflict is real depends on different sources of error potentially affecting big datasets (assembly, stochastic, and systematic error). Here, we apply a recently developed methodology (GGI or gene genealogy interrogation) and data curation to new and published datasets with more than 1000 exons, 500 ultraconserved element (UCE) loci, and transcriptomic sequences that support incongruent hypotheses. The contentious non-monophyly of the order Characiformes proposed by two studies is shown to be a spurious outcome induced by sample contamination in the transcriptomic dataset and an ambiguous result due to poor taxonomic sampling in the UCE dataset. By exploring the effects of number of taxa and loci used for analysis, we show that the power of GGI to discriminate among competing hypotheses is diminished by limited taxonomic sampling, but not equally sensitive to gene sampling. Taken together, our results reinforce the notion that merely increasing the number of genetic loci for a few representative taxa is not a robust strategy to advance phylogenetic knowledge of recalcitrant groups. We leverage the expanded exon capture dataset generated here for Characiformes (206 species in 23 out of 24 families) to produce a comprehensive phylogeny and a revised classification of the order.

Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator.

Is there only one electric eel species? For two and a half centuries since its description by Linnaeus, Electrophorus electricus has captivated humankind by its capacity to generate strong electric discharges. Despite the importance of Electrophorus in multiple fields of science, the possibility of additional species-level diversity in the genus, which could also reveal a hidden variety of substances and bioelectrogenic functions, has hitherto not been explored. Here, based on overwhelming patterns of genetic, morphological, and ecological data, we reject the hypothesis of a single species broadly distributed throughout Greater Amazonia. Our analyses readily identify three major lineages that diverged during the Miocene and Pliocene-two of which warrant recognition as new species. For one of the new species, we recorded a discharge of 860 V, well above 650 V previously cited for Electrophorus, making it the strongest living bioelectricity generator.

Data on the multilocus molecular phylogenies of the Neotropical fish family Prochilodontidae (Teleostei: Characiformes).

The data presented herein support the article "Molecular phylogenetics of the Neotropical fish family Prochilodontidae (Teleostei: Characiformes)" (B.F. Melo, B.L. Sidlauskas, B.W. Frable, K. Hoekzema, R.P. Vari, C. Oliveira, 2016) [1], which inferred phylogenetic relationships of the prochilodontids from an alignment of three mitochondrial and three nuclear loci (5279 bp) for all 21 recognized prochilodontid species and 22 related species. Herein, we provide primer sequences, museum voucher information and GenBank accession numbers. Additionally, we more fully describe the maximum-likelihood and Bayesian phylogenetic analyses of the concatenated dataset, detail the Bayesian species tree analysis, and provide the maximum likelihood topologies congruent with prior morphological hypotheses that were compared with the unconstrained tree using Shimodaira-Hasegawa tests.

VARSEDIG: an algorithm for morphometric characters selection and statistical validation in morphological taxonomy.

We present and discuss VARSEDIG, an algorithm which identifies the morphometric features that significantly discriminate two taxa and validates the morphological distinctness between them via a Monte-Carlo test. VARSEDIG is freely available as a function of the RWizard application PlotsR (http://www.ipez.es/RWizard) and as R package on CRAN. The variables selected by VARSEDIG with the overlap method were very similar to those selected by logistic regression and discriminant analysis, but overcomes some shortcomings of these methods. VARSEDIG is, therefore, a good alternative by comparison to current classical classification methods for identifying morphometric features that significantly discriminate a taxon and for validating its morphological distinctness from other taxa. As a demonstration of the potential of VARSEDIG for this purpose, we analyze morphological discrimination among some species of the Neotropical freshwater family Characidae.

Development of the splanchnocranium in Prochilodus argenteus (Teleostei: Characiformes) with a discussion of the basal developmental patterns in the Otophysi.

Development of the mandibular, hyoid and gill arches, which constitute the splanchnocranium, are described for Prochilodus argenteus, order Characiformes, one of the basal lineages of the Otophysi. Development was examined from just hatched larvae through juveniles using whole specimens cleared and counterstained for cartilage and bone as well as histological preparations. Observations are compared with the developmental trends reported for Cypriniformes, the basalmost clade of the Otophysi. Shortened developmental sequences for Prochilodus compared to the cypriniform Catostomus were discovered in the ontogeny of the ceratohyals, ceratobranchials 1-5, epibranchials 1-4 and the symplectic portion of the hyosymplectic. Prochilodus also differs from Catostomus in having the basihyal plus the anterior copula appearing at different stages of ontogeny rather than simultaneously. Contrary to previous assumptions, developmental information indicates that hypobranchial 4 as well as likely basibranchial 5 are present in Prochilodus. Various developmental patterns in Prochilodus considered basal for the Otophysi, the predominant component of the Ostariophysi, are likely conserved from patterns prevalent in basal groups in the Actinopterygii.

Revalidation and redescription of Steindachnerina nigrotaenia and redescription of S. insculpta (Characiformes: Curimatidae)

Steindachnerina nigrotaenia is resurrected from the synonym of S. brevipinna and considered a valid species. The previous designation of the lectotype of S. nigrotaenia is considered invalid and a new lectotype is designated herein. Steindachnerina nigrotaenia and S. insculpta are redescribed based on type specimens and on additional material from the rio Paraguai and the upper rio Paraná basins, respectively. The two species can be separated by the number of scales of the lateral line and of the transverse series and by phylogenetic analyses of molecular data.(AU)

Steindachnerina nigrotaenia é retirada da sinonímia de S. brevipinna e considerada uma espécie válida. A designação do lectótipo de S. nigrotaenia é considerada inválida e um novo lectótipo é aqui designado. Steindachnerina nigrotaenia e S. insculpta são redescritas com base no material tipo e em exemplares adicionais das bacias do rio Paraguai e alto rio Paraná, respectivamente. As duas espécies se diferenciam pelo número de escamas da linha lateral e da série transversal e por análises filogenéticas de dados moleculares.(AU)

The jaw adductor muscle complex in teleostean fishes: evolution, homologies and revised nomenclature (osteichthyes: actinopterygii).

The infraclass Teleostei is a highly diversified group of bony fishes that encompasses 96% of all species of living fishes and almost half of extant vertebrates. Evolution of various morphological complexes in teleosts, particularly those involving soft anatomy, remains poorly understood. Notable among these problematic complexes is the adductor mandibulae, the muscle that provides the primary force for jaw adduction and mouth closure and whose architecture varies from a simple arrangement of two segments to an intricate complex of up to ten discrete subdivisions. The present study analyzed multiple morphological attributes of the adductor mandibulae in representatives of 53 of the 55 extant teleostean orders, as well as significant information from the literature in order to elucidate the homologies of the main subdivisions of this muscle. The traditional alphanumeric terminology applied to the four main divisions of the adductor mandibulae - A1, A2, A3, and Aω - patently fails to reflect homologous components of that muscle across the expanse of the Teleostei. Some features traditionally used as landmarks for identification of some divisions of the adductor mandibulae proved highly variable across the Teleostei; notably the insertion on the maxilla and the position of muscle components relative to the path of the ramus mandibularis trigeminus nerve. The evolutionary model of gain and loss of sections of the adductor mandibulae most commonly adopted under the alphanumeric system additionally proved ontogenetically incongruent and less parsimonious than a model of subdivision and coalescence of facial muscle sections. Results of the analysis demonstrate the impossibility of adapting the alphanumeric terminology so as to reflect homologous entities across the spectrum of teleosts. A new nomenclatural scheme is proposed in order to achieve congruence between homology and nomenclature of the adductor mandibulae components across the entire Teleostei.

The untold story of the caudal skeleton in the electric eel (ostariophysi: gymnotiformes: electrophorus).

Alternative hypotheses had been advanced as to the components forming the elongate fin coursing along the ventral margin of much of the body and tail from behind the abdominal region to the posterior margin of the tail in the Electric Eel, Electrophorus electricus. Although the original species description indicated that this fin was a composite of the caudal fin plus the elongate anal fin characteristic of other genera of the Gymnotiformes, subsequent researchers proposed that the posterior region of the fin was formed by the extension of the anal fin posteriorly to the tip of the tail, thereby forming a "false caudal fin." Examination of ontogenetic series of the genus reveal that Electrophorus possesses a true caudal fin formed of a terminal centrum, hypural plate and a low number of caudal-fin rays. The confluence of the two fins is proposed as an additional autapomorphy for the genus. Under all alternative proposed hypotheses of relationships within the order Gymnotiformes, the presence of a caudal fin in Electrophorus optimized as being independent of the occurence of the morphologically equivalent structure in the Apteronotidae. Possible functional advantages to the presence of a caudal fin in the genus are discussed.

A new genus of Neotropical rheophilic catfishes, with four new species (Teleostei: Siluriformes: Pseudopimelodidae)

Rhyacoglanis, a new genus of the South American freshwater catfish family Pseudopimelodidae is described from cis-Andean portions of the continent. Rhyacoglanis is distinguished from other genera of the family by three synapomorphies: presence of a light blotch on the cheek; a connection between the middle of the dark caudal-fin stripe and the dark caudal-peduncle pigmentation; and 30-35 total vertebrae. Species of Rhyacoglanis are rheophilic and strongly associated with rapids and other swift-flowing waters. A phylogenetic analysis based on 41 morphological characters yields a hypothesis of monophyly of the Pseudopimelodidae and Rhyacoglanis. Pimelodus pulcher Boulenger, 1887, from the western Amazon basin is designated as type-species of the new genus and redescribed. Four new species are described: Rhyacoglanis annulatus, from the río Orinoco basin, with a nearly ringed dark band on the caudal peduncle, and a larger distance between anus and anal-fin origin; R. epiblepsis, from the rio Madeira basin, with numerous dark spots scattered on the body, and rounded caudal-fin lobes; R. paranensis, from the upper rio Paraná basin, with three distinct dark bands on the body, and 31-33 total vertebrae; and R. seminiger, from the rio Juruena basin, with subdorsal and subadipose dark bands fused anteroposteriorly, and a separate dark band on the caudal peduncle.(AU)

Rhyacoglanis, um novo gênero de bagre da América do Sul da família Pseudopimelodidae é descrito da porção cisandina do continente. Rhyacoglanis é distinto de Pseudopimelodus e outros gêneros da família por três sinapomorfias: uma mancha clara na região lateral da cabeça, a faixa escura da nadadeira caudal confluente ao meio da mancha escura do pedúnculo caudal, e 30-35 vértebras totais. As espécies de Rhyacoglanis são reofílicas com uma forte preferência por corredeiras e outras águas rápidas. Uma análise filogenética com base em 41 caracteres morfológicos produziu uma hipótese de monofilia da família e de Rhyacoglanis. Pimelodus pulcher Boulenger, 1887 é designada a espécie-tipo do gênero novo e redescrita. Quatro espécies novas são descritas: Rhyacoglanis annulatus, da bacia do río Orinoco, com a banda escura do pedúnculo caudal aproximadamente circular, e uma maior distância entre o ânus e a origem da nadadeira anal; R. epiblepsis, da bacia do rio Madeira, com o corpo pintalgado e lobos da nadadeira caudal arredondados; R. paranensis, da bacia do alto rio Paraná, com três bandas escuras distintas no corpo, e 31-33 vértebras totais; e R. seminiger, da bacia do rio Juruena, com uma banda escura larga no tronco composta pelas bandas subdorsal e subadiposa fundidas anteroposteriormente, e uma banda escura separada no pedúnculo caudal.(AU)

Checklist of Gymnotiformes (Osteichthyes: Ostariophysi) and catalogue of primary types

A list of all valid names of species of Neotropical electric fishes (Gymnotiformes) is presented herein. The list is arranged by family and genus and includes all available synonyms. The list is comprehensive through 2016 and includes 240 valid species distributed among 34 genera and five families, including one monotypic genus known only from the fossil record. The presented classification reflects recently published interpretations about the validity of the included names which, in general, are widely accepted. When the validity of a particular name is disputed in recent literature, we followed one of the published interpretations and provide relevant information on the alternate interpretation(s) in the remarks section of that name. Synonymies of some names need to be considered tentative, inasmuch as the types underlying those names are either absent or appear to be based on more than one taxon. First reviser actions (e.g., lectotype and neotype designations, resolution of simultaneous synonyms, etc.) are reported and include erroneous subsequent attempts at problem resolutions. Herein, we include one new first reviser action by selecting Gymnotus aequilabiatus Humboldt, 1805, as type species of Sternopygus because previous attempts to select a type did not follow the provisions of the Code of Zoological Nomenclature.(AU)

Uma lista de todas as espécies válidas de peixes elétricos neotropicais (Gymnotiformes) é apresentada. A lista é organizada por família e gênero, e inclui todos os sinônimos válidos. A lista encontra-se atualizada até 2016 e inclui 240 espécies válidas viventes distribuídas entre os 34 gêneros e cinco famílias, e um gênero monotípico conhecido apenas por registros fósseis. A presente classificação reflete as recentes interpretações publicadas sobre a validade dos nomes incluídos, nos quais, em geral, são amplamente aceitos. Quando a validade de um nome em particular é disputada na literatura recente, nós seguimos uma das interpretações publicadas, e fornecemos informações relevantes sobre a(s) interpretação(ões) na seção de comentários do nome em questão. Sinônimos de alguns nomes precisam ser considerados com cautela, tendo em vista que os tipos para estes nomes são ausentes, ou parecem ser baseados em mais de um táxon. As primeira ações de revisão (e.g., designação de lectótipos e neótipos, resolução na designação simultânea de sinônimos, etc.) são registradas e incluem os esforços errôneos subsequentes para a solução do problema. Aqui, nós incluímos uma primeira ação de revisão selecionando Gymnotus aequilabiatus Humboldt, 1805, como a espécie-tipo de Sternopygus, porque os esforços prévios para selecionar o tipo não seguiram as recomendações do Código de Nomenclatura Zoológica.(AU)

Protocheirodon, a new genus of Characidae (Teleostei: Characiformes) with the redescription of the poorly known protocheirodon pi

Protocheirodon, a new genus of the Characidae, is proposed to include a species previously assigned to Leptagoniates . This action is supported by molecular and morphological phylogenetic hypotheses that place Protocheirodon pi as the sister group of the remaining tribes in the Cheirodontinae versus the traditional assignment of the species to the Aphyocharacinae. The phylogenetic position of Protocheirodon is recognized as a new tribe, the Protocheirodontini. Protocheirodon pi , originally described based on a small number of specimens from a single location in the río Mamoré basin in the southwestern Amazon, is redescribed on the basis of larger series of specimens from the western and central portions of the Amazon basin.

Protocheirodon, um gênero novo de Characidae é proposto para incluir uma espécie previamente alocada em Leptagoniates . Esta decisão é suportada por hipóteses filogenéticas moleculares e morfológicas que apontam Protocheirodon pi como grupo-irmão das demais tribos de Cheirodontinae, ao invés da alocação tradicional em Aphyocharacinae. A posição filogenética de Protocheirodon é reconhecida como uma tribo nova, Protocheirodontini. Protocheirodon pi , originalmente descrito com base em poucos exemplares de uma única localidade na bacia do rio Mamoré, no sudoeste da Amazônia, é redescrito com base em grandes séries de espécimes coletados em rios das porções centrais e ocidentais da bacia do rio Amazonas.

New species of the catfish genus Tatia (Siluriformes: Auchenipteridae) from the rio Teles Pires, upper rio Tapajós basin, Brazil

Analysis of specimens of the auchenipterid catfish genus Tatia collected in the rio Teles Pires, a tributary of the rio Tapajós, along the border between the states of Pará and Mato Grosso, Brazil, revealed it to be an undescribed species. This new species is distinguished from all congeners with the exception of T. carolae and T. musaica by the intense, clearly demarcated, dark coloration on the dorsal and to varying degrees lateral and sometimes ventrolateral portions of the body versus the very lightly colored regions which are translucent in life on the remainder of the body. Various details of head, body and dorsal and caudal-fin pigmentation along with meristic and morphometric features distinguish the new species from T. carolae and T. musaica. The new species provides further evidence that the upper and middle rio Tapajós is a region of ichthyofaunal endemism.

A análise de espécimes do bagre auquenipterídeo do gênero Tatia, provenientes do rio Teles Pires, um tributário do rio Tapajós, na divisa entre os estados do Pará e Mato Grosso, Brasil, revelou se tratar de uma espécie ainda não descrita. Esta espécie nova distingue-se de seus congêneres, com exceção de T. carolae e T. musaica, por sua intensa e distintamente demarcada, coloração escura sobre o dorso a variados graus na porção lateral e algumas vezes ventro-lateral do corpo em contraste com regiões de coloração muito clara, a qual é translúcida em vida, no restante do corpo. Vários detalhes da pigmentação da cabeça, corpo, e nadadeira caudal e dorsal juntamente com características merísticas e morfométricas distinguem a espécie nova de T. carolae e T. musaica. A espécie nova fornece evidência adicional de que a porção alta e média da bacia do rio Tapajós é uma região de endemismo da ictiofauna.

New species of cyphocharax (characiformes: curimatidae) from the upper rio Negro, Amazon basin

A new species of Cyphocharax, Curimatidae, apparently endemic to the blackwater upper rio Negro of the Amazon basin in northern Brazil, is described. The new species is readily distinguished from its congeners by the presence of a distinctly longitudinally elongate, posteriorly vertically expanding patch of dark pigmentation along the midlateral surface of the caudal peduncle, with the patch extending from the base of the middle caudal-fin rays anteriorly past the vertical through the posterior terminus of the adipose fin. The new species additionally differs from all congeners in details of body and fin pigmentation and meristic and morphometric ratios. Evidence for the assignment of the species to Cyphocharax and the occurrence of other species of the Curimatidae apparently endemic to the upper rio Negro catchment is discussed.

Uma espécie nova de Cyphocharax, Curimatidae, aparentemente endêmica das águas escuras do rio Negro, bacia amazônica no norte do Brasil, é descrita. A espécie nova é prontamente distinguida de suas congêneres pela presença de uma mancha escura distintamente alongada longitudinalmente e posteriormente expandida na vertical ao longo da superfície lateral do pedúnculo caudal, sendo estendida da base dos raios medianos da nadadeira caudal até a linha vertical do término da nadadeira adiposa. Adicionalmente, a espécie nova difere de todas as congêneres nos detalhes do corpo, pigmentação das nadadeiras e nas proporções merísticas e morfométricas. As evidências para alocação da espécie no gênero Cyphocharax e a ocorrência de outras espécies de Curimatidae aparentemente endêmicas do alto rio Negro são discutidas.