Phylogeographic patterns of Cyphocharax from trans-Andean rivers and northward expansion to lower Central America (Teleostei, Curimatidae).

Phylogenetic analyses of mitochondrial and nuclear data of 31 specimens of Cyphocharax from trans-Andean rivers support the presence of one lineage of Cyphocharax aspilos in Lago Maracaibo and three cryptic lineages of Cyphocharax magdalenae: (1) Cauca-Magdalena and Ranchería, (2) León and Atrato, and (3) Chucunaque-Tuira, Santa María, and Chiriquí basins of Central America. Results suggest that the Serranía del Perijá facilitated Late Miocene cladogenetic events, whereas post-Isthmian C. magdalenae expansion was enabled by gene flow across the lower Magdalena valley and Central American lowlands. Time-calibrated phylogenetics indicate that the C. magdalenae colonized lower Central America in the Pliocene (3.7 MYA; Ma), the divergence Atrato-Magdalena occurred in Late Pliocene (3.0 Ma) and the split Ranchería-Magdalena during the Middle Pleistocene (1.3 Ma). Updated geographic distribution data support the hypothesis that the Cordillera de Talamanca functions as a barrier to northward expansion of C. magdalenae in Central America.

Molecular species delimitation and description of a new species of Phenacogaster (Teleostei, Characidae) from the southern Amazon basin.

Phenacogaster is the most species-rich genus of the subfamily Characinae with 23 valid species broadly distributed in riverine systems of South America. Despite the taxonomic diversity of the genus, little has been advanced about its molecular diversity. A recent molecular phylogeny indicated the presence of undescribed species within Phenacogaster that is formally described here. We sampled 73 specimens of Phenacogaster and sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene in order to undertake species delimitation analyses and evaluate their intra- and interspecific genetic diversity. The results show the presence of 14 species, 13 of which are valid and one undescribed. The new species is known from the tributaries of the Xingu basin, the Rio das Mortes of the Araguaia basin, and the Rio Teles Pires of the Tapajós basin. It is distinguished by the incomplete lateral line, position of the humeral blotch near the pseudotympanum, and shape of the caudal-peduncle blotch. Meristic data and genetic differentiation relative to other Phenacogaster species represent strong evidence for the recognition of the new species and highlight the occurrence of an additional lineage of P.franciscoensis.

Phylogenomic analysis of the Neotropical fish subfamily Characinae using ultraconserved elements (Teleostei: Characidae).

Characinae is one of the most species-rich subfamilies of Characidae and holds special taxonomic importance because it includes Charax, type-genus of Characidae and Characiformes. Currently, the monophyly and the hypotheses of intergeneric and interspecific relationships of Characinae are based on a few morphological and molecular studies but all with low species coverage. Given their diversity, taxonomic importance, and the lack of a taxon-dense phylogeny, we sought to buttress the systematic understanding of Characinae collecting DNA sequence data from ultraconserved elements (UCEs) of the genome from 98 specimens covering 57 species (61%) plus 17 characiforms as outgroups. We used maximum likelihood, Bayesian inference, and coalescent-based species tree approaches and the resulting phylogeny with 1,300 UCE loci (586,785 characters) reinforced the monophyly of the subfamily as well as of six genera: Acestrocephalus, Charax, Cynopotamus, Galeocharax, Phenacogaster, and Roeboides. The phylogeny provides a hypothesis of intergeneric and interspecific relationships for the subfamily with Phenacogaster sister to all genera, and Acanthocharax sister to Cynopotamini (Cynopotamus (Acestrocephalus Galeocharax)) and Characini (Charax Roeboides). We propose a new tribe Acanthocharacini to allocate Acanthocharax, two subclades for Phenacogaster, two for Cynopotamus, three for Charax, and reinforced the four subclades for Roeboides previously identified by morphological studies. Additionally, we generated a time-calibrated phylogeny for Characinae that suggested an initial diversification during the Miocene at around 19 million years ago and discussed historical biogeographic events for major subclades. The results obtained here will contribute to the development of further research on the evolutionary processes modulating species diversification in Characinae.

Biogeography of curimatid fishes reveals multiple lowland-upland river transitions and differential diversification in the Neotropics (Teleostei, Curimatidae).

The Neotropics harbors a megadiverse ichthyofauna comprising over 6300 species with approximately 80% in just three taxonomic orders within the clade Characiphysi. This highly diverse group has evolved in tropical South America over tens to hundreds of millions of years influenced mostly by re-arrangements of river drainages in lowland and upland systems. In this study, we investigate patterns of spatial diversification in Neotropical freshwater fishes in the family Curimatidae, a species-rich clade of the order Characiformes. Specifically, we examined ancestral areas, dispersal events, and shifts in species richness using spatially explicit biogeographic and macroevolutionary models to determine whether lowlands-uplands serve as museums or cradles of diversification for curimatids. We used fossil information to estimate divergence times in BEAST, multiple time-stratified models of geographic range evolution in BioGeoBEARS, and alternative models of geographic state-dependent speciation and extinction in GeoHiSSE. Our results suggest that the most recent common ancestor of curimatids originated in the Late Cretaceous likely in lowland paleodrainages of northwestern South America. Dispersals from lowland to upland river basins of the Brazilian and Guiana shields occurred repeatedly across independently evolving lineages in the Cenozoic. Colonization of upland drainages was often coupled with increased rates of net diversification in species-rich genera such as Cyphocharax and Steindachnerina. Our findings demonstrate that colonization of novel aquatic environments at higher elevations is associated with an increased rate of diversification, although this pattern is clade-dependent and driven mostly by allopatric speciation. Curimatids reinforce an emerging perspective that Amazonian lowlands act as a museum by accumulating species along time, whereas the transitions to uplands stimulate higher net diversification rates and lineage diversification.

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.].

Molecular and morphological diversity in species of Kronichthys (Teleostei, Loricariidae) from Atlantic coastal rivers of Brazil.

The Neotropical catfish genus Kronichthys contains three species distributed along coastal rivers of southern and southeastern Brazil. Although phylogenetic hypotheses are available, the molecular and morphological diversity and species boundaries within the genus remain unexplored. In this study, the authors generated mitochondrial data for 90 specimens combined with morphometric and meristic data to investigate species diversity, species boundaries and putative morphological signatures in Kronichthys. Phylogenetic and species delimitation results clearly show the presence of four genetic lineages, three within Kronichthys heylandi along the coast from Rio de Janeiro to southern São Paulo and a single lineage encompassing both the nominal species Kronichthys lacerta and Kronichthys subteres from the Ribeira de Iguape basin to Santa Catarina in southern Brazil. Nonetheless, morphological data show overlapped ranges in morphometrics and a definition of only two morphotypes, with clear phenotypic differences in the teeth number: K. heylandi differs from K. subteres + K. lacerta by the higher number of premaxillary teeth (30-52 vs. 19-28) and higher number of dentary teeth (28-54 vs. 17-28). Headwater captures and connections of paleodrainages because of sea-level fluctuations represent the two major biogeographic processes promoting species diversification and lineage dispersal of Kronichthys in the Atlantic coastal range of Brazil.

Phylogenomics of the Neotropical fish family Serrasalmidae with a novel intrafamilial classification (Teleostei: Characiformes).

The Neotropical fish family Serrasalmidae comprises 16 extant genera and 101 species widespread through major Neotropical rivers with relevant importance for regional fisheries and aquaculture. The monophyly of Serrasalmidae and the recognition of three main clades are recurrent between morphological and molecular phylogenies. However, both intergeneric and interspecific relationships within each of those clades remain uncertain. Here, we used 81 terminals of 69 species (68%) and all 16 genera of Serrasalmidae to sequence 1553 loci of ultraconserved elements (UCEs), multiple nuclear loci widely applied in phylogenetic studies, and performed maximum likelihood, Bayesian, and species tree analyses. We obtained highly supported phylogenies in all applied methods corroborating the monophyly of Serrasalmidae and the three-clade hypotheses herein proposed as two subfamilies and two tribes: (Colossomatinae (Serrasalminae (Myleini + Serrasalmini))). Morphological features for each subfamily involve the absence (Colossomatinae) or presence (Serrasalminae) of a pre-dorsal spine. Morphological diagnoses among tribes include the pre-dorsal spine being continuous (Myleini) or discontinuous (Serrasalmini) relative to the first unbranched dorsal-fin ray. Our results highlight the complexity of the relationships especially the non-monophyly of Myleus, Mylesinus, Myloplus, Tometes, and Utiaritichthys within Myleini, as well as of Serrasalmus and Pristobrycon within Serrasalmini.

Molecular delimitation and taxonomic revision of the wimple piranha Catoprion (Characiformes: Serrasalmidae) with the description of a new species.

A taxonomic revision of wimple piranhas of the genus Catoprion is performed in combination with a molecular analysis using mtDNA. Molecular phylogenetic analyses of 49 specimens using genetic distances, conventional likelihood and four delimitation methods yielded two distinct lineages of Catoprion, with the morphological analyses of 198 specimens of Catoprion corroborating the molecular results. We provide a redescription of Catoprion mento, from the Paraguay, Orinoco, and tributaries of western Amazon basin, keeping Mylesinus macropterus as a junior synonym of C. mento, and the description of Catoprion absconditus n. sp., from the Amazon and Essequibo basins. C. absconditus n. sp. differs from C. mento by the presence of 86-94 perforated scales in the lateral line (vs. 65-86 scales) and the presence of 35-40 circumpeduncular scales (vs. 29-34 scales). The distribution of C. mento follows the Amazonas-Paraguay-Orinoco lowlands, whereas C. absconditus follows the eastern Amazon biogeographic pattern.

Phylogenomic analysis of trichomycterid catfishes (Teleostei: Siluriformes) inferred from ultraconserved elements.

The family Trichomycteridae is one of the most diverse groups of freshwater catfishes in South and Central America with eight subfamilies, 41 genera and more than 300 valid species. Its members are widely distributed throughout South America, reaching Costa Rica in Central America and are recognized by extraordinary anatomical specializations and trophic diversity. In order to assess the phylogenetic relationships of Trichomycteridae, we collected sequence data from ultraconserved elements (UCEs) of the genome from 141 specimens of Trichomycteridae and 12 outgroup species. We used a concatenated matrix to assess the phylogenetic relationships by Bayesian inference (BI) and maximum likelihood (ML) searches and a coalescent analysis of species trees. The results show a highly resolved phylogeny with broad agreement among the three distinct analyses, providing overwhelming support for the monophyletic status of subfamily Trichomycterinae including Ituglanis and Scleronema. Previous relationship hypotheses among subfamilies are strongly corroborated, such as the sister relationship between Copionodontinae and Trichogeninae forming a sister clade to the remaining trichomycterids and the intrafamilial clade TSVSG (Tridentinae-Stegophilinae-Vandelliinae-Sarcoglanidinae-Glanapteryginae). Monophyly of Glanapteryginae and Sarcoglanidinae was not supported and the enigmatic Potamoglanis is placed outside Tridentinae.

New species of Curimatopsis from the río Caroni, Orinoco basin, Venezuela, with comments on C. macrolepis (Characiformes: Curimatidae)

A new species of Curimatopsis is described from the highlands of the western Guiana Shield in the río Carapo and río Paragua, tributaries of the río Caroni in the Orinoco basin, southeastern Venezuela. The new species belongs to the Curimatopsis macrolepis clade due to its possession of a long lower jaw that projects past the anterior margin of the upper jaw, and separate first and second hypurals. The new species is diagnosed from remaining species of the Curimatopsis macrolepis clade by having a small-sized inconspicuous dark spot on the midlateral surface of the caudal peduncle, by details of body and fin pigmentation, and by additional morphometric characters. The distribution of C. macrolepis in the Amazon and Orinoco basins is updated based on the examination of museum specimens.(AU)

Uma nova espécie de Curimatopsis é descrita da porção oeste do Escudo das Guianas dos ríos Carapo e Paragua, tributários do río Caroni, bacia do Orinoco no sudeste da Venezuela. A nova espécie pertence ao clado Curimatopsis macrolepis por possuir uma maxila inferior longa que se projeta além da margem anterior da maxila superior e primeiro e segundo hipurais separados. A nova espécie é diagnosticada das demais espécies do clado Curimatopsis macrolepis por possuir uma mácula escura pequena, inconspícua na superfície lateral do pedúnculo caudal, por detalhes de pigmentação do corpo e nadadeiras, e por dados morfométricos adicionais. A distribuição geográfica de C. macrolepis nas bacias do rio Amazonas e río Orinoco é atualizada baseada na análise de espécimes depositados em museus.(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)

Molecular Data Reveal Multiple Lineages in Piranhas of the Genus Pygocentrus (Teleostei, Characiformes).

Carnivorous piranhas are distributed in four serrasalmid genera including Pygocentrus, which inhabit major river basins of South America. While P. cariba and P. piraya are endemics of the Orinoco and São Francisco basins, respectively, P. nattereri is widely distributed across the Amazonas, Essequibo, lower Paraná, Paraguay, and coastal rivers of northeastern Brazil, with recent records of introductions in Asia. Few studies have focused on the genetic diversity and systematics of Pygocentrus and the putative presence of additional species within P. nattereri has never been the subject of a detailed molecular study. Here we aimed to delimit species of Pygocentrus, test the phylogeographic structure of P. nattereri, and access the origin of introduced specimens of P. nattereri in Asia. Phylogenetic analyses based on a mitochondrial dataset involving maximum-likelihood tree reconstruction, genetic distances, Bayesian analysis, three delimitation approaches, and haplotype analysis corroborate the morphological hypothesis of the occurrence of three species of Pygocentrus. However, we provide here strong evidence that P. nattereri contains at least five phylogeographically-structured lineages in the Amazonas, Guaporé (type locality), Itapecuru, Paraná/Paraguay, and Tocantins/Araguaia river basins. We finally found that the introduced specimens in Asia consistently descend from the lineage of P. nattereri from the main Rio Amazonas. These results contribute to future research aimed to detect morphological variation that may occur in those genetic lineages of Pygocentrus.

Phylogenomic reappraisal of the Neotropical catfish family Loricariidae (Teleostei: Siluriformes) using ultraconserved elements.

Neotropical freshwaters host more than 6000 fish species, of which 983 are suckermouth armored catfishes of the family Loricariidae - the most-diverse catfish family and fifth most species-rich vertebrate family on Earth. Given their diversity and ubiquitous distribution across many habitat types, loricariids are an excellent system in which to investigate factors that create and maintain Neotropical fish diversity, yet robust phylogenies needed to support such ecological and evolutionary studies are lacking. We sought to buttress the systematic understanding of loricariid catfishes by generating a genome-scale data set (1041 loci, 328,330 bp) for 140 species spanning 75 genera and five of six previously proposed subfamilies. Both maximum likelihood and Bayesian analyses strongly supported the monophyly of Loricariidae. Our results also reinforced the established backbone of loricariid interrelationships: Delturinae as sister to all other analyzed loricariids, with subfamily Rhinelepinae diverging next, followed by Loricariinae sister to Hypostominae + Hypoptopomatinae. Previous DNA-based relationships within Hypostominae and Loricariinae were strongly supported. However, we evaluated for the first time DNA-based relationships among many Hypoptopomatinae genera and found significant differences with this subfamily's current genus-level classification, prompting several taxonomic changes. Finally, we placed our topological results within a fossil-calibrated temporal context indicating that early Loricariidae diversification occurred across the Cretaceous-Paleogene boundary ∼65 million years ago (Ma). Our study lays a strong foundation for future research to focus on relationships among species and the macroevolutionary processes affecting loricariid diversification rates and patterns.

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)

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.

Little Divergence Among Mitochondrial Lineages of Prochilodus (Teleostei, Characiformes).

Evidence that migration prevents population structure among Neotropical characiform fishes has been reported recently but the effects upon species diversification remain unclear. Migratory species of Prochilodus have complex species boundaries and intrincate taxonomy representing a good model to address such questions. Here, we analyzed 147 specimens through barcode sequences covering all species of Prochilodus across a broad geographic area of South America. Species delimitation and population genetic methods revealed very little genetic divergence among mitochondrial lineages suggesting that extensive gene flow resulted likely from the highly migratory behavior, natural hybridization or recent radiation prevent accumulation of genetic disparity among lineages. Our results clearly delimit eight genetic lineages in which four of them contain a single species and four contain more than one morphologically problematic taxon including a trans-Andean species pair and species of the P. nigricans group. Information about biogeographic distribution of haplotypes presented here might contribute to further research on the population genetics and taxonomy of Prochilodus.

A new species of Tetragonopterus (Characiformes: Characidae) from Central Amazon lowlands, Brazil

A new species of Tetragonopterus is described from lowland rivers of Central Amazon. It differs from congeners by having a vertically-oriented patch of dark pigmentation limited to posterior portion of the caudal peduncle and by bearing five thin and sharp teeth on dentary, along with other morphometric and meristic features. We hypothesize that the new taxon belongs to the herein named "Tetragonopterus anostomus clade" that includes T. anostomus, T. denticulatus, T. kuluene, and T. juruena.(AU)

Uma espécie nova de Tetragonopterus é descrita de rios de terra baixa da Amazônia Central. Ela difere de suas congêneres por possuir uma mancha escura orientada verticalmente, limitada à porção posterior do pedúnculo caudal, e por possuir cinco dentes principais finos e afiados no dentário, além de outras características morfométricas e merísticas. Nós levantamos a hipótese que o novo táxon pertença ao clado Tetragonopterus anostomus, o qual inclui T. anostomus, T. denticulatus, T. kuluene e T. juruena.(AU)

Cyphocharax boiadeiro, a new species from the upper rio Araguaia, Amazon basin, Brazil (Characiformes: Curimatidae).

Cyphocharax boiadeiro, new species, is described from the upper rio Araguaia, a tributary of the Amazon basin in central Brazil. The new species is readily distinguished from its congeners by the presence of a distinct longitudinal dark stripe from supracleithrum to the caudal peduncle and by a combination of morphometric, meristic, and pigmentation features. Morphological characters supporting putative subunits of Cyphocharax are also discussed.

New species of Parotocinclus (Siluriformes: Loricariidae) from coastal drainages of Rio de Janeiro, southeastern Brazil.

A new species of Parotocinclus is described from tributaries of rio São João, an Atlantic coastal river of Rio de Janeiro, southeastern Brazil. The new species is distinguished from its congeners by the possession of a triangular patch of dark pigmentation on the anterior portion of the dorsal-fin base, a fully developed adipose fin, complete exposure of the ventral surface of the pectoral girdle, and a distinctive pigmentation pattern of the caudal fin. The caudal fin has a hyaline background with a large black blotch covering its anterior portion, tapering irregularly through distal portions of the ventral lobe with a hyaline rounded area, and a small patch of dark pigmentation on distal portions of the dorsal lobe.