RESUMEN

A new species of Characidium shared by adjacent tributaries of the upper portions of the Tapajós and Xingu river basins is described. Characidium varii, new species, can be distinguished from the congeners by having distinctly speckled pattern of colouration, including dark blotches on cheek and ventral surface of head, by having conspicuous dark marks on fins, along with a single row of dentary teeth, isthmus completely covered by scales, 14 circumpeduncular scales, and swimbladder reduced. Molecular data reinforce the validation of the new species. The distribution of C. varii supports the hypothesis of the existence of a faunistic mixing between Tapajós and Xingu river basins, corresponding to the region of the Serra do Cachimbo and surrounding areas, previously proposed in the literature.

RESUMEN

A new miniature species of Characidium is described from the midde rio Guaporé, rio Madeira basin, Rondônia, Brazil. The new species can be readily distinguished from all congeners by the sexual dichromatism, with females having narrow dark bars on body absent in males, and by the presence, in both sexes, of a black midventral dashed line extending from area between contralateral pectoral fins to at least the anal-fin origin. It can also be diagnosed from congeners by having strongly tricuspid teeth, with well developed and similar sized cusps in the premaxilla and outer series of dentary, and short lateral line with 6­8 perforated scales. Morphological novelties to Characidium observed in the new species include a rounded process on the first pleural rib near the vertebra, three or four haemal spines of the first caudal vertebrae distinctly elongate, neural and haemal spines of the antepenultimate vertebra not reaching origins of dorsal and ventral procurrent rays nor the origin of the caudal-fin rays.(AU)

Uma nova espécie miniatura de Characidium é descrita do médio rio Guaporé, bacia do rio Madeira, Rondônia, Brasil. A nova espécie pode ser facilmente distinguida de todas as congêneres pelo dicromatismo sexual, com barras escuras estreitas no corpo das fêmeas ausentes nos machos, e por ter uma linha preta mediana ventral tracejada em ambos os sexos, que se estende da área entre as bases das nadadeiras peitorais até pelo menos a origem da nadadeira anal. A espécie também pode ser diagnosticada das congêneres por ter dentes fortemente tricúspides, com cúspides bem desenvolvidas e de tamanho semelhante no pré-maxilar e série externa do dentário, e linha lateral curta com 6­8 escamas perfuradas. Novidades morfológicas para Characidium observadas na nova espécie incluem presença de um processo arredondado na primeira costela pleural próximo à vértebra, três ou quatro espinhos hemais das primeiras vértebras caudais distintamente alongados, espinhos neurais e hemais da antepenúltima vértebra não atingindo as origens dos raios procorrentes dorsal e ventral, nem a origem dos raios da nadadeira caudal.(AU)

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The Northeastern Mata Atlântica freshwater ecoregion (NMAF) is recognized for the high degree of endemism of its ichthyofauna, whose evolutionary and biogeographic histories are still poorly understood. Oligosarcus acutirostris is a freshwater fish species endemic to the NMAF, which is distributed in coastal rivers and streams draining Bahia, Espírito Santo, and part of Minas Gerais states in eastern Brazil. Its widespread distribution in currently isolated river basins along the NMAF prompted this study, which aimed to understand what scenarios would be involved in determining its current distribution pattern, and to contribute to a better understanding of the biogeographic history of the NMAF. For this, mitochondrial and nuclear DNA sequences were analyzed based on samples from different localities along the species distribution, including its type locality. Overall, phylogeographic analyses indicate a strong genetic structure within the species evidenced mainly by the non-sharing of haplotypes between most of the basins analyzed. According to the AMOVA results, the current distribution of haplotypes is better explained by the Pleistocene coastal paleodrainages. The results are also used to test and complement a biogeographic hypothesis previously proposed for the drainages of the NMAF.(AU)

A ecorregião de água doce Mata Atlântica Nordeste (NMAF) é reconhecida pelo alto grau de endemismo da sua ictiofauna, cujas histórias evolutiva e biogeográfica ainda são pouco compreendidas. Oligosarcus acutirostris é uma espécie de peixe de água doce endêmica da NMAF, que está distribuída em rios e riachos costeiros que drenam os estados da Bahia, Espírito Santo e parte de Minas Gerais, no leste do Brasil. Sua ampla distribuição em bacias atualmente isoladas ao longo da NMAF motivou este estudo, que teve como objetivos entender quais cenários estariam envolvidos na determinação do seu padrão atual de distribuição e contribuir para uma melhor compreensão da história biogeográfica da NMAF. Para isto, foram analisadas sequências de DNA nuclear e mitocondrial, a partir de amostras de diferentes localidades ao longo da distribuição da espécie, incluindo sua localidade tipo. No geral, as análises filogeográficas indicam forte estruturação genética na espécie, evidenciada principalmente pelo não compartilhamento de haplótipos entre a maioria das bacias analisadas. De acordo com os resultados da AMOVA, a distribuição atual dos haplótipos é melhor explicada pelas paleodrenagens costeiras do Pleistoceno. Os resultados obtidos também são utilizados para testar e complementar hipótese biogeográfica previamente proposta para as drenagens da NMAF.(AU)

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A new species of Characidium is described from the tributaries of the upper and middle rio Doce basin, Minas Gerais, Brazil. The new species is distinguished from most congeners, except C. cricarense, C. hasemani, C. helmeri, C. kalunga, C. pterostictum, C. schubarti, C. summus, and C. travassosi by lacking scales in the area between the anterior limit of the isthmus and the anterior margin of cleithrum. The new species differs from the aforementioned species by a series of characters, including the presence of the adipose fin, 2­-4 scales between the anus and anal fin, two rows of dentary teeth, presence of the parietal branch of the supraorbital canal, 4 scale rows above the lateral line, and absence of two conspicuous inclined dark bands on each caudal-fin lobe. The new species further differs from most congeners with an unscaled ventral surface of the isthmus by the presence of 33-34 pored scales on the lateral line and by the dark dashes on the caudal fin-rays not forming well-defined bands.(AU)

Uma nova espécie de Characidium é descrita de afluentes do alto e médio curso da bacia do rio Doce, Minas Gerais, Brasil. A nova espécie se distingue da maioria das congêneres, exceto C. cricarense, C. hasemani, C. helmeri, C. kalunga, C. pterostictum, C. schubarti, C. summus e C. travassosi pela falta de escamas na área entre o limite anterior do istmo e a margem anterior do cleitro. A nova espécie difere das espécies acima mencionadas por uma série de caracteres, incluindo a presença de nadadeira adiposa, 2-4 escamas entre o ânus e a nadadeira anal, duas séries de dentes no dentário, ramo parietal do canal supraorbital presente, 4 séries de escamas acima da linha lateral e ausência de duas bandas escuras inclinadas em cada lobo da nadadeira caudal. A nova espécie difere ainda mais da maioria das congêneres com superfície ventral sem escamas no istmo por ter 33-34 escamas perfuradas na linha lateral e traços escuros nos raios da nadadeira caudal não formando bandas bem definidas.(AU)

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Characidium cacah, new species, apparently endemic to the rio das Velhas sub-basin, upper rio São Francisco basin, Brazil, is described. The new species is easily distinguished from congeners, except C. chicoi, C. helmeri, C. mirim, C. nana, C. nupelia, C. stigmosum and C. xavante, by having an incomplete lateral line and for lacking an adipose fin. The new species can be diagnosed from the aforementioned species by a series of characters, including the presence of 12 circumpeduncular scales, the isthmus completely scaled, a thin inconspicuous or dashed midlateral dark stripe, the absence of a conspicuous peduncular blotch, and humeral blotch and basicaudal spot variably marked.

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Tambaba environmentally protected area is situated on the south coast of Paraíba State, within the Atlantic forest biome of the northeastern region in Brazil. The Tambaba environmentally protected area consists of a series of independent drainages: Graú, Mucatú, and Bucatú river micro-basins, and Caboclo River sub-basin that belongs to Gurugi River micro-basin. Ichthyological samples were collected in five scientific expeditions between months of June and July in 2015. Twenty-nine sites from different habitats (e.g., spanning tributaries, streams, rivers, and estuaries) were accessed for sampling. A total of 44 species distributed within 38 genera, 25 families, and 17 orders were assigned to the Tambaba hydrographic region. Freshwater species comprised 36% (n = 16) and marine-estuarine species 64% (n = 28) of the total collected specimens. Two invasive species occur in the freshwater sites: Cichla monoculus and Poecilia reticulata. Cheirodon jaguaribensis, Cichlasoma orientale, and Crenicichla brasiliensis are endemic to the Brazilian Northeast region with the first species restricted to the Northeast Caatinga and Coastal drainages hydrographic ecoregion.(AU)

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Tambaba environmentally protected area is situated on the south coast of Paraíba State, within the Atlantic forest biome of the northeastern region in Brazil. The Tambaba environmentally protected area consists of a series of independent drainages: Graú, Mucatú, and Bucatú river micro-basins, and Caboclo River sub-basin that belongs to Gurugi River micro-basin. Ichthyological samples were collected in five scientific expeditions between months of June and July in 2015. Twenty-nine sites from different habitats (e.g., spanning tributaries, streams, rivers, and estuaries) were accessed for sampling. A total of 44 species distributed within 38 genera, 25 families, and 17 orders were assigned to the Tambaba hydrographic region. Freshwater species comprised 36% (n = 16) and marine-estuarine species 64% (n = 28) of the total collected specimens. Two invasive species occur in the freshwater sites: Cichla monoculus and Poecilia reticulata. Cheirodon jaguaribensis, Cichlasoma orientale, and Crenicichla brasiliensis are endemic to the Brazilian Northeast region with the first species restricted to the Northeast Caatinga and Coastal drainages hydrographic ecoregion.

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Characidium tapuia, a new species apparently endemic to the rio Parnaíba basin, Brazil, is described. The new species is easily distinguished from congeners, except C. lanei, C. nana, and C. samurai, by having a broad and conspicuous dark lateral stripe, extending from the tip of snout to the end of caudal peduncle and by the absence of dark vertical bars on body of specimens larger than 23.0 mm SL. Characidium tapuia differs from the aforementioned species by a series of features, including 12 circumpeduncular scales (vs. 13 or 14 in C. lanei and C. samurai), presence of parietal branch of the supraorbital canal (vs. absence in C. lanei and C. nana), complete lateral line and adipose fin present (vs. lateral line incomplete and adipose fin absent in C. nana), and midlateral stripe with irregular borders (vs. lateral stripe with overall straight borders in C. samurai).

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Abstract: The Mamanguape River Basin is located in a peripheral semi-arid area of South America, with its headwaters and middle reaches running through the Caatinga (from wetter to drier) and its lower reaches through the Atlantic Forest. The objective of this study was to inventory the fish fauna of the Mamanguape river basin through a comprehensive sampling and to discuss its ichthyofaunal dominance pattern. Sampling was conducted between 2015 and 2016 at 38 points throughout. The main river course was sampled at 18 fixed points during two expeditions (dry and wet seasons) using traw nets, cast nets, and dip nets, with a standardized effort. The tributaries were sampled during the dry season at 20 points using an adaptaptation of the AquaRAP methodology. A total of 32 freshwater fish species belonging to 26 genera, 16 families and six orders were recorded, predominantly from the order Characiformes and the family Characidae. Astyanax fasciatus had widest distribution and greatest abundance in the basin. Siluriformes were the second most prevalent order, with five species recorded. Cichla cf. monoculus, Poecilia reticulata and Oreochromis niloticus were non-native records for the basin. Apareiodon davisi, an Endangered species, was recorded.

Resumo: A bacia do rio Mamanguape está situada numa área periférica do semiárido, suas nascentes e porção média correndo em área de domínio da Caatinga - de mais úmida a mais seca, e sua porção baixa em área de Mata Atlântica. O estudo teve por objetivo inventariar a fauna de peixes da bacia do rio Mamanguape, através de uma amostragem abrangente de suas drenagens, e discutir o padrão de dominância de sua ictiofauna. O trabalho de coleta foi realizado entre os anos de 2015 e 2016, em 38 pontos distribuídos em toda a bacia. Dezoito pontos foram amostrados ao longo do curso principal do rio (Pontos Fixos), em duas expedições (seca e cheia), através de arrasto, tarrafa e puçá, com esforço padronizado. Os afluentes foram amostrados durante a estação seca, em 20 pontos, utilizando-se uma adaptação da metodologia AquaRap. Foram registradas 32 espécies de peixes de água doce pertencentes a 26 gêneros, 16 famílias e seis ordens, com predominância da ordem Characiformes e da família Characidae, sendo Astyanax fasciatus a espécie de maior distribuição e abundância na bacia. Siluriformes foi a segunda ordem de maior predominância, com cinco espécies. Cichla cf. monoculus, Oreochromis niloticus e Poecilia reticulata constituíram registros de introdução na bacia; foi registrada Apareiodon davisi, uma espécie ameaçada de extinção (Em Perigo).

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Abstract: Freshwater ichthyofauna from Brazil Northeast region was considered as being poorly known until recent years, with a considerable number of publications becoming available in the last decade. The present study provides an inventory of freshwater fish species from the Paraíba do Norte River basin located in Paraíba State, Brazil. This inventory is intended to contribute to the of knowledge to the regional fish diversity, pre-transposition of the São Francisco River. Collecting data was obtained from ichthyological databases of both national and foreign institutions. A total of 47 freshwater fish species are registered within the Paraíba do Norte River basin, represented by 38 genera, 20 families and six orders. Characiformes, comprising 47% (22 species), Cichliformes, and Siluriformes are among the most representative orders, 19% (9 species) each, of total recorded species. Seven species of Cichliformes are reported as introduced species in this basin. Cyprinodontiformes and Gobiiformes also registered in this region and correspond to 5% (two species) and Gymnotiformes, Perciformes and Synbranchiformes, 2% (one species each) of total recorded species. Paraíba do Norte River basin stands out in the current national scenario as it comprises the first region from the Mid-Northeastern Caatinga freshwater ecoregion to receive water from the transposition of the São Francisco River. The current inventory is important as it provides scientific data related to the ichthyofauna of Paraíba do Norte River basin prior to the commencement of the river transposition process. An identification key is also given for the freshwater fish species of the region.

Resumo: A ictiofauna de água doce do Nordeste brasileiro durante muito tempo foi considerada pouco conhecida. No entanto, este paradigma vem sendo mudado nas últimas décadas com aumento significativo no número de publicações desta ictiofauna. Para contribuir com mais informações sobre a diversidade de peixes do Nordeste brasileiro, o presente estudo realizou um inventário das espécies de peixes de água doce da bacia do rio Paraíba do Norte, localizada no Estado da Paraíba, pré-transposição do Rio São Francisco. Os dados foram provenientes de acervos ictiológicos de instituições nacionais e estrangeiras. Foram registradas 47 espécies, distribuídas em 38 gêneros, 20 famílias e seis ordens de peixes na bacia do rio Paraíba do Norte. As ordens mais representativas foram Characiformes (22 espécies/47% do total), Cichliformes e Siluriformes (9/19%). Sete espécies de Cichliformes são reportadas como introduzidas na bacia. Além das ordens citadas, foram registrados dois Cyprinodontiformes and Gobiiformes (2/5%), e Gymnotiformes, Perciformes e Synbranchiformes (1/2% cada). A bacia do Paraíba do Norte tem se destacado no cenário atual por ser a primeira da região Nordeste Médio-Oriental a receber águas da transposição do rio São Francisco. Com isso, este inventário é de fundamental importância, por apresentar dados da ictiofauna da bacia do rio Paraíba do Norte antes da transposição. Esse trabalho também apresenta uma chave para identificação das espécies de peixes da bacia.