Corydoras fulleri (Siluriformes: Callichthyidae), a new catfish species from the rio Madeira basin, Peru.

A new long-snouted Corydoras species is described from two tributaries of the río Manuripe and a tributary of the río Madre de Dios, rio Madeira basin, Peru. Corydoras fulleri can be distinguished from its congeners by having the following features: (a) branch of the temporal sensory canal at sphenotic, which gives rise to the supraorbital canal, with two pores; (b) upper tooth plate of branchial arch with three series of teeth; (c) area at the corner of the mouth, ventral to the maxillary barbel, with a small fleshy flap; (d) two moderate-sized dark-brown or black blotches on caudal-fin base, one on its lateral portion and another one on its dorsal portion, blotches variably diffuse and/or fused with each other; (e) absence of a dark-brown or black stripe transversally crossing the orbit; (f) a longitudinal dark-brown or black stripe on the postdorsal region of flank midline, variably fused with the lateral peduncular blotch, some specimens with slender, longitudinally elongated, dark-brown or black blotch on flank midline, forming a dash-like marking, stripe or dash-like blotch diffuse in some specimens; and (g) region around dorsal-fin origin generally lacking dark brown or black blotch, or displaying diffuse blotch.

The crystalline waters of the Bodoquena Plateau revealed Hypostomus froehlichi (Siluriformes: Loricariidae), a new armored catfish from the rio Paraguay basin in Brazil.

The menaced and poorly-known waters of the Bodoquena Plateau revealed a new resident, the stunning Hypostomus froehlichi sp. n., a large-sized armored catfish, which is finally described after more than twenty years since its discovery. The Bodoquena Plateau is drained by the rio Paraguay basin, and is located in the state of Mato Grosso do Sul, Brazil. The new species differs from its congeners on the Bodoquena crystalline waters by having teeth with morphological and numerical variation in adult specimens. There is a continuous range of specimens having about 20 thick and worn teeth to specimens having about 50 thin teeth with intact crowns and lanceolate main cusps. Additional diagnostic characters are: dentaries angled more than 90 degrees, dark blotches, one plate bordering supraoccipital, moderate keel along dorsal series of plates, usually two rows of blotches per interradial membrane on dorsal, pectoral and ventral fins, and by attaining comparatively large size. Hypostomus froehlichi seems to be endemic to the area of the Bodoquena Plateau, in rivers draining to the rio Miranda. The description of the new species reveals a potential conservation flagship species as it is one of the most seen and documented fish by visitors and divers in the clear waters from the touristic, though menaced, Bonito region in Brazil.

A new arc-striped species of Corydoras Lacépède, 1803 (Teleostei: Callichthyidae) from the Peruvian Amazon.

A new Corydoras is described from the Blanco and Ucayali river basins in Peru. The new species can be distinguished from its congeners by having the following features: (I) posterior margin of dorsal-fin spine with laminar serrations directed towards the origin of the spine; (II) a long, wide, arched, and continuous black stripe, which runs parallel to the dorsal profile of the body, extending at least from the region below anterior origin of dorsal fin to the anterior half of the ventral caudal-fin lobe; (III) a black stripe transversally crossing the eye, forming the typical mask-like blotch; mask clearly not fused to arched stripe in most specimens; some specimens with mask separated from arched stripe by a thin line around the suture between neurocranium (in the region composed by the posteroventral margin of parieto-supraoccipital plus the posterodorsal margin of the compound pterotic) and first dorsolateral body plate; (IV) posterior margin of pectoral-fin spine with laminar serrations directed towards the origin of the spine; (V) pointed snout, presenting a long mesethmoid, with anterior tip larger than 50% of the entire length of the bone; and (V) ventral surface of trunk covered by small, non-coalescent platelets. A discussion on the possible positive adaptive value of the arc-striped color pattern is also provided.

A journey through the Amazon Middle Earth reveals Aspidoras azaghal (Siluriformes: Callichthyidae), a new species of armoured catfish from the rio Xingu basin, Brazil.

Aspidoras azaghal n. sp. was discovered during a multitaxonomic scientific expedition to the remote Amazon Terra do Meio region in tributaries to the rio Xingu basin, Pará, Brazil. The new species can be promptly distinguished from its congeners by the following combination of features: (a) absence of the first dorsal-fin element; (b) parieto-supraoccipital fontanel located medially on bone; (c) absence of a longitudinal dark-brown or black stripe along flank midline; (d) ventral surface of trunk covered by clearly smaller, irregular and/or roundish platelets; (e) inner laminar expansion of infraorbital 1 well developed; (f) relatively wide frontal bone, with width equal to half of entire length; (g) absence of a thick, longitudinal conspicuous dark-brown stripe along dorsal portion of flank; and (h) poorly developed serrations on posterior margin of the pectoral-fin spine. Besides morphological evidence, the molecular analyses indicated significant differences between the new species and its congeners, with A. albater and A. raimundi as its closest species, showing 6.53% of genetic differentiation in both cases. The intraspecific molecular data revealed gene flow (peer fixation index, FST = 0.05249, P > 0.05, for the cytochrome oxidase I (COI) marker and FST = -0.01466, P > 0.05, for the control region) between specimens upstream and downstream from a 30-m height waterfall at the type-locality, which therefore represent a single population. Furthermore, it was possible to observe a unidirectional gene flow pattern, with genetic diversity increasing in the downstream direction.

Taxonomic revision of Hypostomus albopunctatus (Siluriformes: Loricariidae) reveals a new piece of the Hypostomus jigsaw in the upper Rio Paraná basin.

Hypostomus albopunctatus was described from the Rio Piracicaba, a tributary of the Rio Tietê, upper Rio Paraná basin. Nevertheless, specimens attributed to this species are commonly found throughout other river systems in the upper Rio Paraná basin and present varying degrees of morphological variation. A taxonomic review of H. albopunctatus based on large series of specimens from many localities throughout the upper Rio Paraná basin was carried out. Results support H. lexi, H. niger and H. scaphyceps as junior synonyms. Hypostomus albopunctatus differs from all congeners except H. heraldoi by having pectoral-fin spine equal to or shorter than pelvic-fin spine (v. longer); it differs from H. heraldoi by having white or light yellow spots on the body and fins (v. dark brown or black spots). Despite conspicuous variation related to the shape and size of the spots and snout morphology, both spot and snout patterns overlapped among the examined populations, thus this variation was inferred to be intraspecific within a widely distributed H. albopunctatus.

Taxonomic review of the typical long-snouted species of Corydoras (Siluriformes: Callichthyidae) from the río de La Plata basin

The typical long-snouted species of Corydoras from the río de La Plata basin were reviewed herein, and the previously proposed synonymy of Corydoras ellisae was corroborated. Corydoras areio and C. aurofrenatus are diagnosed from their congeners, excluding those in lineage 1, by the following features: temporal sensory canal in sphenotic with two pores; upper tooth plate of branchial arch with three or four series of teeth; fleshy flap at mouth corner. Corydoras areio differs from all lineage 1 congeners by having infraorbital 2 with relatively wider posterior laminar expansion; absence of large patches of black pigmentation on the body and absence of conspicuous concentration of dark brown or black chromatophores on anterior portion of the dorsal fin; and presence of blotches on flanks not aligned in longitudinal series. Corydoras aurofrenatus differs from all lineage 1 congeners by having ventral surface of head and trunk densely covered by small, not coalescent platelets; middle portion of flank with two or three dark brown or black patches (below the dorsal-fin, below the adipose-fin base, and on the caudal peduncle base, diffuse and variably present), patches decreasing in size posteriorly; poorly developed fleshy flap at the corner of mouth; anteroventral portion of cleithrum exposed.(AU)

As espécies típicas de focinho longo de Corydoras da bacia do río de La Plata foram revisadas, e a sinonímia proposta anteriormente de Corydoras ellisae foi corroborada. Corydoras areio e C. aurofrenatus são diagnosticadas de seus congêneres, excluindo aquelas da linhagem 1, pelas seguintes características: canal sensorial temporal no esfenótico com dois poros; placa dentária superior do arco branquial com três ou quatro séries de dentes; aba carnosa no canto da boca. Corydoras areio difere de todos os congêneres da linhagem 1 pelo infraorbital 2 com expansão laminar posterior relativamente mais ampla; ausência de grandes manchas de pigmentação preta no corpo e ausência de concentração conspícua de cromatóforos marrom-escuros ou pretos na porção anterior da nadadeira dorsal; presença de manchas laterais não alinhadas em série longitudinal. Corydoras aurofrenatus difere de todas as congêneres da linhagem 1 pela superfície ventral da cabeça e do tronco densamente coberta por pequenas plaquetas não coalescentes; porção média lateral com duas ou três manchas marrom-escuras ou pretas (abaixo da nadadeira dorsal, abaixo da base da nadadeira adiposa, e na base do pedúnculo caudal, difusa e variavelmente presente), manchas diminuindo de tamanho posteriormente; aba carnosa pouco desenvolvida no canto da boca; porção anteroventral do cleitro exposta.(AU)

Deconstructing an octogenarian misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin.

After 80 years of misidentifications, the analysis of the holotype of Corydoras arcuatus plus several non-type specimens attributed to this species allowed its recognition and also revealed a new species, both sharing the following diagnostic features: a long, arched, continuous black stripe that runs parallel to the dorsal profile of the body and extends at least from the anterior margin of the first dorsolateral body plate to the posterior portion of caudal peduncle; absence of transverse black bars on caudal fin; infraorbital 2 in contact with sphenotic and compound pterotic. In addition to these features, C. arcuatus can be distinguished from congeners by having the posterior margin of both dorsal and pectoral spines with laminar serrations directed towards their origins. The new species can be additionally distinguished from its congeners by presenting the following combination of features: ventral surface of trunk entirely or partially covered by relatively large and coalescent platelets; absence of spots or blotches on dorsal fin; and posterior margin of both dorsal and pectoral spines with serrations directed towards their tips. Finally, an identification key to all arc-striped species of Corydoras is provided.

Redescription of Corydoras undulatus Regan, 1912 (Siluriformes: Callichthyidae), with comments on the identity of Corydoras latus Pearson, 1924.

A redescription of Corydoras undulatus Regan, 1912 is presented. The original description of C. undulatus is very succinct, as is its diagnosis, which is based only on external morphology. Additional information in the scientific literature on this species is scarce. Specimens from the distribution area of this species were analyzed; Paraná and Paraguay river basins in Argentina, Uruguay river basin in Argentina, Brazil and Uruguay, and the Laguna dos Patos system in Brazil. Morphological analysis, principal component analysis (PCA), meristic comparison and osteological description were performed. Corydoras undulatus can be distinguished from its congeners mainly by having the following combination of characters: mesethmoid short, with anterior tip short, smaller than 50% of the entire bone length; posterior margin of the pectoral-fin spine with nearly all serrations directed towards origin of spine; pectoral-fin spine with conical serrations; and its peculiar color pattern. The analysis of the material from the different basins did not indicate relevant morphological differences, suggesting that the species presents a wide distribution in La Plata and Laguna dos Patos drainages. The shared geographic distribution between these two systems is also present in other fish species. The current work presents data about the type locality, taxonomy, osteology, distribution and ontogenetic variation of color pattern in C. undulatus. Comments on the identity of a very similar congener, Corydoras latus, will also be provided.

Aspidoras mephisto, new species: The first troglobitic Callichthyidae (Teleostei: Siluriformes) from South America.

Aspidoras mephisto n. sp. is described from the Anésio-Russão cave system, upper Tocantins River basin, Goiás, Brazil. The species can be readily distinguished from its congeners by troglomorphic features and also by presenting the following combination of features: infraorbital 1 generally with well-developed ventral laminar; or moderately developed; poorly-developed serrations on posterior margin of pectoral spine; nuchal plate not externally visible; dorsal fin, even in conspicuously colored specimens, with only dark brown or black chromatophores concentrated on rays, forming spots in some specimens; membranes hyaline; or sparse dark brown or black chromatophores on membranes, not forming any conspicuous pattern; and inner laminar expansion of infraorbital 1 moderately developed. Information about its habitat, ecology, behaviour and conservation status are provided and also a brief description of the juvenile stage.

Is coexistence between non-native and native Erythrinidae species mediated by niche differentiation or environmental filtering? A case study in the upper Paraná River floodplain

The limiting similarity theory predicts that divergence in the functional traits of native and introduced species is an essential component in species establishment, as introduced species must occupy a niche that is unoccupied by resident species. On the other hand, the environmental filtering hypothesis predicts convergence between introduced and native species, as both possess traits that make them adapted to the local abiotic environment. Morphology, spatial co-occurrence, diet, feeding selectivity, and niche breadth and overlap of Erythrinidae were evaluated to detect possible mechanisms acting in the coexistence between non-native and native species. Native (Hoplias sp. B and Hoplias cf. malabaricus) and non-native (Hoplerythrinus unitaeniatus and Hoplias mbigua) species presented differences in morphological traits, spatial co-occurrence, diet, selectivity, and niche breadth and overlap. The mechanisms mediating species coexistence seem to vary according to species. The absence of spatial and feeding overlap suggests that non-native species H. unitaeniatus occupy a different niche than native species, supporting its successful establishment without eliminating the native species. However, low feeding overlap and similar morphologies between non-native and native species of Hoplias point to environmental filters; in this case, the non-native H. mbigua is able to establish due to similarities in functional traits.(AU)

Teorias sobre nicho ecológico afirmam que divergência em traços funcionais entre espécies nativas e introduzidas são essenciais ao estabelecimento da espécie introduzida, pois estas devem ocupar um nicho não utilizado pelas espécies residentes. Por outro lado, a teoria de filtros ambientais afirma a convergência entre espécies introduzidas e nativas, pois ambas possuem traços funcionais que fazem com que essas espécies estejam mais adaptadas as variáveis ambientais. Foram avaliadas a morfologia, ocorrência espacial, dieta, seletividade alimentar, sobreposição e largura de nicho em Erythrinidae para detectar possíveis mecanismos atuando na coexistência de espécies nativas e não nativas. Espécies nativas (Hoplias sp. B e Hoplias cf. malabaricus) e não nativas (Hoplerythrinus unitaeniatus e Hoplias mbigua) apresentaram diferenças em todos os atributos testados. Os mecanismos mediando a coexistência de espécies nativas e não nativas parecem variar de acordo com a espécie considerada. A ausência de sobreposição espacial e na dieta sugere que a espécie não nativa H. unitaeniatus ocupa um nicho distinto que as espécies nativas, favorecendo seu estabelecimento sem eliminar as espécies nativas, apontando para segregação de nicho. Por outro lado, morfologias similares, porém com diferentes dietas foram observadas para as espécies de Hoplias, sugerindo que as espécies coexistem devido à filtros ambientais, assim, neste caso, a espécie não nativa H. mbigua é capaz de se estabelecer no novo ambiente devido à similaridades em traços funcionais.(AU)

A new species of Aspidoras (Siluriformes: Callichthyidae) from a small coastal drainage in northeastern Brazil

A new species of Aspidoras from the rio da Dona basin, a small coastal river drainage in Bahia State, is described herein. The new taxon differs from its congeners by presenting infraorbital 1 with well-developed ventral laminar expansion, nuchal plate nearly reaching to or sometimes contacting posterior process of parieto-supraoccipital, anterior tip of nuchal plate just posterior to dorsal margin of first dorsolateral body plate, and blotches on dorsal half of dorsolateral body plates and/or ventral half of ventrolateral body plates fused with midlateral series of blotches, forming three or four enlarged and oblique black blotches.(AU)

Uma nova espécie de Aspidoras da bacia do rio da Dona, uma pequena drenagem costeira do estado da Bahia, é aqui descrita. O novo táxon difere de suas congêneres por apresentar infraorbital 1 com expansão laminar ventral bem desenvolvida, placa nucal quase alcançando ou alcançando o processo posterior do parieto-supraoccipital, extremidade anterior da placa nucal apenas posterior à extremidade dorsal da primeira placa dorsolateral, e três ou quatro manchas pretas grandes na porção lateral mediana do corpo, geralmente inclinadas anterodorsalmente e conectadas à série de manchas dorsais e fusionadas à série ventral de manchas.(AU)

Record of morphological deformities in Corydoras aff. longipinnis in two reservoirs under urban influence in Upper Iguaçu and Southern Coastal basins in Paraná State, Brazil / Registro de anomalias morfológicas em Corydoras aff. longipinnis em dois reservatórios sob influência urbana no Paraná, Brasil

Abstract In this work we report on the presence of morphological deformities in Corydoras aff. longipinnis from two reservoirs in Paraná State, Brazil. The frequency of deformities in the fish populations was 11% in Iraí and 10.5% in Capivari reservoirs. Considering that the frequency may be associated with impacts caused by anthropic activities, this information can be used as a metric in management systems and environmental monitoring.

Resumo Neste trabalho relatamos a presença de deformidades morfológicas em Corydoras aff. longipinnis de dois reservatórios no estado do Paraná, Brasil. A frequência das deformidades observadas nas populações analisadas foi de 11% no reservatório de Iraí e 10,5% no reservatório de Capivari. Considerando que a frequência pode ser associada a impactos causados por atividades antrópicas, essa informação pode ser usada como uma métrica em sistemas de gestão e monitoramento ambiental.

Wrapped in flames: Corydoras hephaestus, a new remarkably colored species from the Rio Madeira basin (Teleostei: Callichthyidae).

A new species of Corydoras is described from the upper Rio Machado, Rio Madeira basin, Rondônia State, Brazil. The new species can be distinguished from its congeners by the absence of contact between the posterior process of the parieto-supraoccipital and the nuchal plate; a ventral laminar expansion of the infraorbital 1 conspicuously developed; and the posterior margin of the pectoral-fin spine with serrations along almost of its entire length, only lacking in the distal portion. Additionally, Corydoras hephaestus possesses dorsal and pectoral spines short, and exhibits an unusual color pattern in life. The conservation status of the new species and other endemic species are briefly commented.

A new long-snouted species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the rio Madeira basin.

A new species of Corydoras is described from the rio Aripuanã, rio Madeira basin, Mato Grosso State, Brazil. The new species can be distinguished from its congeners by the presence of the following features: long mesethmoid, with anterior tip well developed, conspicuously larger than 50% of bone length; posterior margin of dorsal-fin spine with serrations directed towards tip of spine; one to two longitudinal black stripes on flanks; absence of a black blotch across the eyes (mask); absence of a large black blotch on dorsal fin; and transversal black bars on caudal fin. Comments on endemism in interfluvial region between Madeira and Tapajós rivers are briefly discussed.

A new Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the rio Araguaia basin, Brazil, with comments about Corydoras araguaiaensis Sands, 1990

ABSTRACT A new species of Corydoras is described from the rio Araguaia basin, Goiás, Brazil. The new species can be distinguished from its congeners by presenting the following features: infraorbital 1 with very large ventral laminar expansion; infraorbital 2 contacting compound pterotic; flanks densely covered by irregular black spots; and ventral surface of trunk densely covered by coalescent relatively well-developed platelets. It is also discussed the possibility that C. araguaiaensis comprehends a complex of species.

RESUMO Uma espécie nova de Corydoras é descrita da bacia do rio Araguaia, Goiás, Brasil. A espécie nova pode ser distinguida de suas congêneres por apresentar as seguintes características: infraorbital 1 com expansão laminar ventral muito grande; infraorbital 2 em contato com o pterótico composto; flancos densamente cobertos por manchas pretas irregulares e superfície ventral do tronco densamente coberta por plaquetas coalescentes relativamente bem desenvolvidas. Discute-se também a possibilidade de C. araguaiaensis compreender um complexo de espécies.

Revisionary study of the armored catfish Corydoras paleatus (Jenyns, 1842) (Siluriformes: Callichthyidae) over 180 years after its discovery by Darwin, with description of a new species

The taxon known as Corydoras paleatus carries one of the most complex taxonomic histories among Corydoradinae catfishes. A comprehensive review of specimens attributed to that species from several localities was carried out, allowing the clear recognition of C. paleatus and also of a new species previously misidentified as C. paleatus , described herein. Corydoras paleatus can be distinguished from its congeners by presenting the following unique combination of features: perpendicularly directed serrations along entire posterior margin of the pectoral spine; three large black blotches along midline of flank; hyaline or black pectoral fin; and transversal black bars on caudal-fin lobes. Corydoras paleatus is known from the lower rio Paraná basin, coastal rivers from Southern Brazil and Uruguay and rio Uruguai basin. The new species can be distinguished from its congeners by having the following unique combination of features: three large black blotches along midline of flank; three nasal pores; mesethmoid short; infraorbital 2 not in contact with compound pterotic; striated black spots from the snout tip to nuchal plate region; markedly rounded snout; and anterior portion of dorsal fin spotted. The new species is known from the upper rio Uruguai basin, from the rivers Canoas, do Peixe and Pelotas.

O táxon conhecido como Corydoras paleatus carrega uma das histórias taxonômicas mais complexas dentre os bagres Corydoradinae. Uma revisão abrangente de espécimes atribuídos a essa espécie, de várias localidades, foi conduzida. A análise do material colhido permitiu o reconhecimento claro de C. paleatus e também de uma espécie nova, previamente identificada erroneamente como C. paleatus , aqui descrita. Corydoras paleatus pode ser distinguida de suas congêneres por possuir a seguinte combinação única de características: serrilhas perpendicularmente direcionadas ao longo de toda a margem posterior do acúleo peitoral; três manchas pretas grandes ao longo da linha mediana do flanco; nadadeira peitoral hialina ou preta; e barras transversais pretas nos lobos da nadadeira caudal. Corydoras paleatus é conhecida da bacia do baixo rio Paraná, rios costeiros do sul do Brasil e Uruguai, e bacia do rio Uruguai. A espécie nova pode ser distinguida de suas congêneres por possuir a seguinte combinação única de caracteres: três manchas pretas grandes ao longo da linha mediana do flanco; três poros nasais; mesetmóide curto; infraorbital 2 não contatando o pterótico composto; manchas pretas estriadas da ponta do focinho até a região da placa nucal; focinho marcadamente arredondado; e porção anterior da nadadeira dorsal com manchas. A espécie nova é conhecida da bacia do alto rio Uruguai, dos rios Canoas, do Peixe e Pelotas.

A new species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the río Madre de Dios basin, Peru

A new species of Corydoras is described from the río Madre de Dios basin, Peru. The new species can be distinguished from its congeners by presenting the following features: a longitudinal black stripe along midline of flank; mesethmoid short, with anterior portion poorly developed; serrations on posterior margin of pectoral spine directed towards the tip of the spine; dorsal fin with the region of the first branched ray, including membrane, with concentration of black pigmentation, the remaining areas with irregular black blotches; absence of a vertically elongated black blotch across the eyes; conspicuously rounded moderately-developed black spots on the snout; and ventral expansion of infraorbital 1 moderately developed.

Uma espécie nova de Corydoras é descrita da bacia do rio Madre de Dios, Peru. A espécie nova pode ser distinguida de suas congêneres por apresentar as seguintes características: uma faixa preta longitudinal ao longo da linha mediana do flanco; mesetmóide curto, com porção anterior pouco desenvolvida; serrilhas na margem posterior do espinho peitoral voltadas em direção à ponta do espinho; região do primeiro raio ramificado da nadadeira dorsal, incluindo membranas, com concentração de pigmentação preta, as demais áreas com manchas pretas irregulares; ausência de uma mancha preta verticalmente alongada através dos olhos; manchas pretas moderadamente desenvolvidas, conspicuamente arredondadas, no focinho; e expansão ventral do infraorbital 1 moderadamente desenvolvida.

Two new species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the rio Madeira basin, Brazil

Two new species of Corydoras are described from the rio Madeira basin, Brazil. The intermediate long-snouted new species can be distinguished from its congeners by presenting the following combination of features: posterior margin of dorsal-fin spine with laminar serrations directed towards the origin of the spine; presence of two longitudinal black stripes on flanks; anterior portion of dorsal fin with sparse black chromatophores, not forming any conspicuous pattern; absence of a conspicuous black marbled coloration pattern on head; black spots on caudal fin, some spots arranged, forming transversal bars; and brownish dorsal-fin spine. The short-snouted new speciescan be distinguished from its congeners by the following combination of features: short mesethmoid; posterior laminar expansion of infraorbital 2 very reduced, not in contact with compound pterotic; two or three longitudinal black stripes on flanks; absence of an oblique or vertical black blotch across the eye; anterior portion of dorsal fin with sparse black chromatophores, not forming any conspicuous pattern; and ventral surface of trunk naked or covered by sparse platelets.

Duas espécies novas de Corydoras são descritas da bacia do rio Madeira, Brasil. A espécie nova de focinho longo intermediário pode ser distinguida de suas congêneres por apresentar a seguinte combinação de características: margem posterior do espinho da nadadeira dorsal com serrilhas laminares direcionadas para origem do espinho; presença de duas faixas pretas longitudinais nos flancos; porção anterior da nadadeira dorsal com cromatóforos pretos esparsos, sem formar nenhum padrão conspícuo; ausência de um padrão de coloração marmoreado de preto conspícuo na cabeça; manchas pretas na nadadeira caudal, algumas delas alinhadas, formando barras transversais; e espinho dorsal amarronzado. A espécie nova de focinho curto pode ser distinguida de suas congêneres por apresentar a seguinte combinação de características: mesetmóide curto; expansão laminar posterior do infraorbital 2 muito reduzida, sem contato com o pterótico composto; duas ou três faixas pretas longitudinais nos flancos; ausência de uma mancha preta oblíqua ou vertical através do olho; porção anterior da nadadeira dorsal com cromatóforos pretos esparsos, sem formar nenhum padrão conspícuo; e superfície ventral do tronco nua ou coberta por plaquetas esparsas.

Redescription of Corydoras guapore Knaack, 1961 (Siluriformes: Callichthyidae), a midwater Corydoradinae species from the rio Guaporé basin

Corydoras guapore was described from the rio Guaporé, Rondônia State, Brazil, based only in three specimens, two of them merely examined alive in an aquarium and apparently not preserved posteriorly. The current location of these two paratypes is uncertain. In the original description, no standard diagnosis was presented and the descriptive information available is scarce and based only in external morphology. Thus, the aim of this study is to provide a redescription of C. guapore based in several topotypes. Corydoras guapore can be distinguished from its congeners by the presence of a short mesethmoid, with the anterior tip poorly developed; posterior margin of pectoral spine with conical serrations directed towards the origin of the spine; and by the lateral portion of caudal peduncle almost entirely blackened. Information about C. guapore ecology and conservation status are also provided.

Corydoras guapore foi descrita do rio Guaporé, estado de Rondônia, Brasil, com base em somente três exemplares, sendo dois deles apenas examinados vivos em um aquário e aparentemente não preservados posteriormente. A atual localização desses dois parátipos é incerta. Na descrição original, uma diagnose padrão não foi apresentada e as informações descritivas disponíveis são escassas e baseadas apenas em morfologia externa. Dessa forma, o objetivo desse estudo é fornecer uma redescrição de C. guapore baseada em vários topótipos. Corydoras guapore pode ser distinguida de suas congêneres pela presença de mesetmóide curto, com a extremidade anterior pouco desenvolvida, margem posterior do acúleo peitoral com serrilhas cônicas voltadas em direção à origem do acúleo, e pela porção lateral do pedúnculo caudal quase totalmente enegrecida. Informações sobre a ecologia e status de conservação de C. guapore também são fornecidas.

Fishes from Baía da Medalha, southern Pantanal, Brazil: A 20 years review / Peixes da Baía da Medalha, Pantanal Sul, Brasil: Uma revisão de 20 anos

Abstract Located in the Pantanal of Miranda-Abobral, the Baía da Medalha is the largest pond close to the Base de Estudos do Pantanal of the Universidade Federal de Mato Grosso do Sul. The Baía da Medalha has been a study site for several didactic and scientific projects for years. Nevertheless, its fish fauna has never been inventoried. Based on data collected from the beginning of the 1990s up to 2011, we provide a list of fish species from the Baía da Medalha. A total of 97 species were recorded, corresponding to about 40% of the species stated for the Pantanal. Characiformes and Siluriformes were the most species-rich orders, being Characidae and Cichlidae the families with the highest number of species. Regional seasonal flood dynamics and the abundance of aquatic macrophytes may be associated with this high diversity. The representative richness found in this lagoon highlights the importance of such taxonomic surveys to preserve the diversity of aquatic habitats within the Pantanal ecosystem.

Resumo Localizada no Pantanal do Miranda-Abobral, a Baía da Medalha é a maior e mais próxima lagoa da Base de Estudos do Pantanal da Universidade Federal de Mato Grosso do Sul. A Baía da Medalha tem sido área de estudo de diversos projetos didáticos e científicos há anos, entretanto, nenhum inventário sobre sua ictiofauna foi realizado. Aqui é apresentada uma lista de espécies de peixes da Baía da Medalha baseado em dados de coletas do começo da década de 90 até 2011. Um total de 97 espécies foi registrado, correspondendo è cerca de 40% do total de espécies registradas para o Pantanal. Characiformes e Siluriformes foram as ordens mais ricas em espécies, sendo Characidae e Cichlidae as famílias com maior número de espécies. Dinâmicas de inundação sazonal e a abundância de macrófitas aquáticas podem ser associadas a esta alta diversidade. A representativa riqueza encontrada nesta lagoa ressalta a importância de levantamentos taxonômicos a fim de preservar a diversidade dos habitats aquáticos do dentro do ecossistema do Pantanal.