RESUMO
Professor Manuel Pereira de Godoy idealized the Natural History Museum of Pirassununga (MHNP, in Portuguese), State of São Paulo, Brazil, in 1938. In 1962, the MHNP was constructed in the backyard of his house. In 1977, the museum also received the type specimens of fishes from the defunct Estação Experimental de Biologia e Piscicultura de Pirassununga (EEBP). Here we provide notes (including photographs) of 11 type specimens (holotypes, paratypes, and syntypes) of the following 10 species belonging to four families and two orders: Leporinus amae, Astyanax (Astyanax) trierythropterus, Hyphessobrycon flammeus guabirubae, Plecostomus fluviatilis, Plecostomus luteus, Plecostomus topavae, Cetopsorhamdia iheringi, Chasmocranus brachynema, Nannorhamdia schubarti, Pimelodella insignis. Our study provides unprecedented photographic records of several type specimens deposited in MHNP. We expect this study will help in species identification and also assist future taxonomic studies of Neotropical freshwater fishes.
RESUMO
Hypostomus is the most specious genus of Hypostominae, composed of several species with high intraspecific morphological and color pattern variation, making their identification a complex issue. One of the species with problematic identification is Hypostomus tietensis that was described from a single specimen, resulting in uncertainties about its color pattern and correct identification. To assist in this context, cytogenetic analyzes were carried out in three putative populations of H. tietensis from the Upper Paraná River basin, one of them from the type locality. The three populations showed considerable cytogenetic differences, with 2n = 72 chromosomes for the population from the type locality and 2n = 76 chromosomes for the others. Terminal NORs were detected (Ag- and 18S rDNA-FISH), being simple for the type locality population (acrocentric pair 23, long arm) and the Pirapó River (subtelocentric pair 11, short arm), and multiple for Do Campo River (subtelocentric pairs 11 and 12, short and long arm, respectively). C-banding was efficient in differentiating the type locality population from the others. Cytogenetic data revealed that populations from Pirapó and Do Campo rivers, although treated until now as Hypostomus aff. tietensis, represent a cryptic species, and those morphological analyses are necessary to differentiate and for describing this new species.(AU)
Hypostomus é o gênero mais especioso de Hypostominae, composto por várias espécies com uma alta variação tanto morfológica, como no padrão de coloração intraespecífica, tornando sua identificação uma questão complexa. Uma das espécies com identificação complexa é Hypostomus tietensis, a qual foi descrita a partir de um único espécime, resultando em incertezas sobre o seu padrão de cor e identificação. Para auxiliar nesse contexto, análises citogenéticas foram realizadas em três populações putativas de H. tietensis da bacia do Alto rio Paraná, sendo uma delas da localidade tipo. As três populações apresentaram diferenças citogenéticas consideráveis, com 2n = 72 cromossomos para a população da localidade tipo e as demais com 2n = 76. RONs terminais foram detectadas (Ag- e FISH-DNAr 18S), sendo simples para a população da localidade tipo (par acrocêntrico 23, braço longo) e do rio Pirapó (par subtelocêntrico 11, braço curto) e múltiplas para rio Do Campo (pares subtelocêntricos 11 e 12, braço curto e longo, respectivamente), confirmado pela FISH-DNAr 18S. O bandamento C foi eficiente em diferenciar a população da localidade tipo das demais. Os dados citogenéticos revelaram que as populações dos rios Pirapó e do rio Do Campo, embora tratadas até agora como Hypostomus aff. tietensis, representam uma espécie críptica, e que análises morfológicas são necessárias para diferenciar e descrever esta nova espécie.(AU)
Assuntos
Animais , Variação Genética/genética , Peixes-Gato/genética , Especificidade da Espécie , Brasil , Análise Citogenética/veterináriaRESUMO
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.
Assuntos
Peixes-Gato , Nadadeiras de Animais , Animais , Brasil , Paraguai , RiosRESUMO
Environmental disasters affecting Brazilian rivers have been frequent recently, especially involving mining activities. Two recent dam-rupture events suddenly released millions of cubic meters of iron tailings downstream into two major Brazilian watersheds. These events generated major losses to the environment and human life. Additionally, the biodiversity in both watersheds was still incompletely known. Two new species of the armoured catfish genus Hypostomus were discovered in the Rio Paraopeba and surrounding rivers of the Rio São Francisco Basin. The species share some main characteristics including a depressed body, large dark spots on a clearer background and the absence of keels on flanks. However, while one species (Hypostomus freirei sp. n.) has a large mandibular ramus and numerous slender teeth, the other (Hypostomus guajupia sp. n.) has a shorter mandibular ramus and few robust teeth. The discovery of these two new mid-sized fish species emphasizes the presumption that the effects of major environmental disasters cannot be fully estimated as local biodiversity is not completely known. This discovery in a recently devastated area also shows that tough environmental laws for the protection, supervision and mitigation of major impacts are urgently needed in developing countries.
Assuntos
Biodiversidade , Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Animais , Brasil , Desastres , Mandíbula/anatomia & histologia , Mineração , Rios , Especificidade da Espécie , Dente/anatomia & histologiaRESUMO
A new species of Hypostomus with spoon-shaped teeth is described from the Rio Cupari basin, a right margin affluent of the lower Rio Tapajós, Pará State, Brazil. The new species inhabits rocky bottom areas in the main channel of Rio Cupari and its tributaries. The new species can be distinguished from all its congeners, except from the Hypostomus cochliodon group, by having six to eight spoon-shaped teeth, dentaries angled at less than 80° and the absence of a notch between the hyomandibular and the metapterygoid. The new species is distinguished from all species of the H. cochliodon group by its unique colour pattern, containing dark vermiculations on head and anterior portion of the trunk, and by the absence of medial buccal papillae.
Assuntos
Peixes-Gato/classificação , Distribuição Animal , Animais , Brasil , Peixes-Gato/anatomia & histologia , Cor , Pigmentação , Rios , Papilas Gustativas , Dente/anatomia & histologiaRESUMO
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.
Assuntos
Peixes-Gato/classificação , Classificação , Nadadeiras de Animais/anatomia & histologia , Animais , Brasil , Peixes-Gato/anatomia & histologia , RiosRESUMO
In the present study, we describe a new species of Neoplecostomus from central Brazil. The new species is known from Córrego Cachoeira a right tributary of the upper Rio Paraná basin. It can be distinguished from all congeners by absence of adipose fin or azygous plates on the dorsum surface of the caudal peduncle. Additionally, the new species differs from N. botucatu and N. paranensis by having a dark caudal fin with a unique v-shaped hyaline vertical area and a larger lower lip. A discussion on the morphological variation of adipose fin among species of Neoplecostomus is also provided.
Assuntos
Peixes-Gato , Animais , BrasilRESUMO
Hypostomus velhochico sp. n., is described from the rio São Francisco basin, in the states of Minas Gerais and Bahia, Brazil. The new species is mainly distinguished from its congeners by a combination of characters such as slender bicuspid teeth, dentaries angled more than 90 degrees, conspicuous keels along lateral series of plates, small roundish dark spots, one plate bordering supraoccipital, spots aligned along lateral series of plates, and by attaining small to medium size. Hypostomus velhochico is widespread in the rio São Francisco basin and has a more similar general pattern of external morphology to species from the Northeastern Brazilian Coastal drainages than to species of the rio São Francisco basin. Aspects about its ecology and its putative relationship are discussed.
Assuntos
Peixes-Gato , Animais , Brasil , EcologiaRESUMO
Only one species of armored catfish, Ancistrus cirrhosus Valenciennes 1836, has been historically described in the basin of the Paraná River, from Misiones (Argentina). However, the ample variation found in the morphology and coloration of the populations sampled in the tributaries of the Brazilian state of Paraná makes it difficult to establish the real taxonomic status and evolutionary history of the Ancistrus specimens, suggesting that A. cirrhosus is not the only species found in this basin. By combining data on mitochondrial DNA (COI gene) and chromosomal markers from different Ancistrus populations, totaling 144 specimens, in the tributaries of the Paraná, and specimens from Misiones (type-locality of A. cirrhosus), we detected five distinct evolutionary lineages. All the specimens were 2n = 50, but had four distinct karyotype formulae. The results of the Generalized Mixed Yule Coalescent (GYMC) and the genetic distances (uncorrected P-values) between lineages ranged from 3 to 5%. Clusters of 18S rDNA were observed in a single chromosome pair in seven populations of Ancistrus, but at different positions, in some cases, in synteny with the 5S rDNA sites. Multiple 5S sites were observed in all populations. Overall, the cytogenetic data reinforce the genetic evidence of the diversification of lineages, and indicate the existence of candidate species in the study region. The evidence indicates that at least four candidate species of the Ancistrus may coexist in the Paraná basin besides A. cirrhosus. Overall, our results provide a comprehensive scenario for the genetic variation among Ancistrus populations and reinforce the conclusion that the true diversity of the freshwater fish of the Neotropical regions has been underestimated.
RESUMO
Gymnotocinclus canoeiro n. sp. of the Hypoptopomatinae is described from small tributaries of the upper rio Tocantins basin. It is distinguished from G. anosteos by having five characters: (1) the presence of body dermal plates, (2) the pectoral girdle not exposed in ventral view, (3) the pelvic spine longer than pectoral spine in males, (4) the pectoral fin with seven to eight branched rays, and (5) the presence of an adipose fin. Furthermore, maximum likelihood (ML) analysis was used to estimate a molecular phylogeny from previously published data of one nuclear (F-Reticulon 4) and three mitochondrial (16S RNA, COI and CytB) genes. The phylogenetic results revealed the new species as a sister taxon of Gymnotocinclus anosteos within the Otothyrini. We also included samples of Nannoplecostomus eleonorae that appeared sister group to all other Neoplecostomini species, and Plesioptopoma curvidens that appeared within the Neoplecostomini forming a sister clade to all species of Neoplecostomus, except N. ribeirensis and the species of Pareiorhina, except P. rudolphi.
Assuntos
Peixes-Gato , Animais , Masculino , FilogeniaRESUMO
Cytogenetic studies in fish of the Rineloricaria genus have already shown a high variation in diploid number (2n). Along with fusion/fission events for 2n alteration, inversions contribute to the diversification of chromosome formulae within this group. The present study assessed different populations/species of the Rineloricaria aiming to describe the karyotype organization of its members and understand the mechanisms that lead to the variation of chromosome numbers. Cytogenetic data showed distinct karyotype organization among Rineloricaria populations/species studied, ranging in diploid number from 46 to 64 chromosomes, syntopic species and two karyomorphs in Rineloricaria pentamaculata. Using ribosomal DNAs (rDNAs) and TTAGGGn probes by fluorescence in situ hybridization in species with low diploid numbers, we detected sites of 18S rDNA, 5S rDNA, and TTAGGGn in centromeric regions of metacentric chromosomes, which participated in chromosome rearrangements like centric fusions. In species with high 2n, centric fissions probably occurred in karyotypic diversification. In this study, we assessed the telomeric instability, chromosomal breaks, and rearrangements due to interstitial telomeric site vestiges detection, in addition to the probable role of rDNAs in chromosome fusions in karyotypic diversification of this group.
Assuntos
Peixes-Gato/genética , Mapeamento Cromossômico/métodos , Cromossomos/genética , Regulação da Expressão Gênica , Variação Genética , Animais , DNA Ribossômico/genética , Hibridização in Situ Fluorescente , Especificidade da EspécieRESUMO
The cis-Andean genus Aphanotorulus was recently revised and comprises six valid species: A. ammophilus, A. emarginatus, A. gomesi, A. horridus, A. phrixosoma and A. unicolor. Herein, a new species is described from tributaries of the rio Aripuanã basin, in Amazonas and Mato Grosso states, Brazil. The new species is easily distinguished from congeners by its color pattern: caudal fin with upper lobe mostly hyaline with dark spots along rays and membranes, and lower lobe red and without dark spots; and absence of dark spots in the lateral series of mid-ventral plates.(AU)
O gênero cisandino Aphanotorulus foi recentemente revisado e consiste de seis espécies válidas: A. ammophilus, A. emarginatus, A. gomesi, A. horridus, A. phrixosoma e A. unicolor. No presente trabalho, uma nova espécie é descrita dos tributários da bacia do rio Aripuanã, nos estados do Amazonas e Mato Grosso, Brasil. A nova espécie é facilmente distinguida de suas congêneres pelo padrão de coloração: nadadeira caudal com o lobo superior quase totalmente hialino e com pintas escuras ao longo dos raios e membranas, e o lobo inferior vermelho e desprovido de pintas; ausência de manchas escuras na série lateral de placas medianas ventrais.(AU)
Assuntos
Animais , Peixes-Gato/classificação , ClassificaçãoRESUMO
The cis-Andean genus Aphanotorulus was recently revised and comprises six valid species: A. ammophilus, A. emarginatus, A. gomesi, A. horridus, A. phrixosoma and A. unicolor. Herein, a new species is described from tributaries of the rio Aripuanã basin, in Amazonas and Mato Grosso states, Brazil. The new species is easily distinguished from congeners by its color pattern: caudal fin with upper lobe mostly hyaline with dark spots along rays and membranes, and lower lobe red and without dark spots; and absence of dark spots in the lateral series of mid-ventral plates.(AU)
O gênero cisandino Aphanotorulus foi recentemente revisado e consiste de seis espécies válidas: A. ammophilus, A. emarginatus, A. gomesi, A. horridus, A. phrixosoma e A. unicolor. No presente trabalho, uma nova espécie é descrita dos tributários da bacia do rio Aripuanã, nos estados do Amazonas e Mato Grosso, Brasil. A nova espécie é facilmente distinguida de suas congêneres pelo padrão de coloração: nadadeira caudal com o lobo superior quase totalmente hialino e com pintas escuras ao longo dos raios e membranas, e o lobo inferior vermelho e desprovido de pintas; ausência de manchas escuras na série lateral de placas medianas ventrais.(AU)
Assuntos
Animais , Peixes-Gato/classificação , ClassificaçãoRESUMO
We investigated the chromosomal distribution of 18S ribosomal DNA (rDNA) in different populations of 11 species of Hypostomus collected in important Brazilian basins, namely South Atlantic, Upper Paraná, and Paraguay applying the fluorescence in situ hybridization (FISH). Hypostomus cochliodon, Hypostomus commersoni, Hypostomus hermanni, Hypostomus regani, Hypostomus albopunctatus, Hypostomus paulinus, Hypostomus aff. paulinus, Hypostomus iheringii, and Hypostomus mutucae presented multiple 18S rDNA sites while Hypostomus strigaticeps and Hypostomus nigromaculatus exhibited a single pair of chromosomes with 18S rDNA sites. The studied species presented variations in the number and position of these sites. The results accomplished were similar to those obtained by the analysis of AgNORs, revealing the same interspecific variability. Each species exhibited distinctive patterns of AgNOR and 18S rDNA distribution, which can be considered cytogenetic markers in each species of the genus and help improve the discussions on the phylogeny of the group.
Assuntos
Peixes-Gato/genética , Mapeamento Cromossômico , Variação Genética , RNA Ribossômico 18S/genética , Animais , Especificidade da EspécieRESUMO
Ecological opportunity is often proposed as a driver of accelerated diversification, but evidence has been largely derived from either contemporary island radiations or the fossil record. Here, we investigate the potential influence of ecological opportunity on a transcontinental radiation of South American freshwater fishes. We generate a species-dense, time-calibrated molecular phylogeny for the suckermouth armored catfish subfamily Hypostominae, with a focus on the species-rich and geographically widespread genus Hypostomus. We use the resulting chronogram to estimate ancestral geographical ranges, infer historical rates of cladogenesis and diversification in habitat and body size and shape, and test the hypothesis that invasions of previously unoccupied river drainages accelerated evolution and contributed to adaptive radiation. Both the subfamily Hypostominae and the included genus Hypostomus originated in the Amazon/Orinoco ecoregion. Hypostomus subsequently dispersed throughout tropical South America east of the Andes Mountains. Consequent to invasion of the peripheral, low-diversity Paraná River basin in southeastern Brazil approximately 12.5 Mya, Paraná lineages of Hypostomus, experienced increased rates of cladogenesis and ecological and morphological diversification. Contemporary lineages of Paraná Hypostomus are less species rich but more phenotypically diverse than their congeners elsewhere. Accelerated speciation and morphological diversification rates within Paraná basin Hypostomus are consistent with adaptive radiation. The geographical remoteness of the Paraná River basin, its recent history of marine incursion, and its continuing exclusion of many species that are widespread in other tropical South American rivers suggest that ecological opportunity played an important role in facilitating the observed accelerations in diversification.
Assuntos
Adaptação Biológica/genética , Peixes-Gato/classificação , Especiação Genética , Filogenia , Distribuição Animal , Animais , Teorema de Bayes , Tamanho Corporal , Peixes-Gato/anatomia & histologia , Peixes-Gato/genética , Ecossistema , Geografia , Funções Verossimilhança , Análise de Sequência de DNA , América do SulRESUMO
A new species of Hypostomus is described from the rio Quente, rio Paranaíba drainage, in the upper rio Paraná basin in central Brazil. The rio Quente is a peculiar small and shallow fast water stream with water temperatures around 34ºC. The new species is distinguished from all congeners by having the five lateral series of plates with hypertrophied odontodes not aligned in rows and more conspicuous on flanks of caudal peduncle of the larger specimens. The new species is only known from the rio Quente.(AU)
Uma nova espécie de Hypostomus é descrita do rio Quente, drenagem do rio Paranaíba, bacia do alto rio Paraná no Brasil Central. O rio Quente é um riacho peculiar, raso e de correnteza, cujas temperaturas atingem em torno de 34ºC. A espécie nova é distinguida de todas as congêneres por ter as cinco séries de placas laterais com odontódeos hipertrofiados, os quais não são alinhados em fileiras, sendo mais conspícuos nos flancos do pedúnculo caudal nos indivíduos maiores. A espécie nova é conhecida apenas do rio Quente.(AU)
Assuntos
Animais , Peixes-Gato/classificação , Águas Termais/efeitos adversos , Classificação/métodosRESUMO
A new species of Hypostomus is described from the rio Quente, rio Paranaíba drainage, in the upper rio Paraná basin in central Brazil. The rio Quente is a peculiar small and shallow fast water stream with water temperatures around 34ºC. The new species is distinguished from all congeners by having the five lateral series of plates with hypertrophied odontodes not aligned in rows and more conspicuous on flanks of caudal peduncle of the larger specimens. The new species is only known from the rio Quente.
Uma nova espécie de Hypostomus é descrita do rio Quente, drenagem do rio Paranaíba, bacia do alto rio Paraná no Brasil Central. O rio Quente é um riacho peculiar, raso e de correnteza, cujas temperaturas atingem em torno de 34ºC. A espécie nova é distinguida de todas as congêneres por ter as cinco séries de placas laterais com odontódeos hipertrofiados, os quais não são alinhados em fileiras, sendo mais conspícuos nos flancos do pedúnculo caudal nos indivíduos maiores. A espécie nova é conhecida apenas do rio Quente.
Assuntos
Animais , Águas Termais/efeitos adversos , Peixes-Gato/classificação , Classificação/métodosRESUMO
A new species of Neoplecostomus is described from the rio Doce basin representing the first species of this genus in the basin. The new species is distinguished from its congeners by having enlarged, fleshy folds between dentaries, two or three series of developed papillae anterior to premaxillary teeth and a adipose-fin membrane present, and by lacking enlarged odontodes along snout lateral margins in mature males, a well-developed dorsal-fin spinelet wider than dorsal-fin spine base, lower number of lateral-line figs and developed membrane on the dorsal portion of the first, second and third pelvic-fin branched rays. Additionally, we present a brief discussion of biogeographic scenarios that may explain the distribution of the new species in the rio Doce basin. We suggested that the ancestral lineage of the new species reached the rio Doce from the upper portions of rio Paraná drainages about 3.5 Mya (95% HPD: 1.6-5.5) indicating a colonization route of the N. doceensis ancestral lineage from the south end of Serra do Espinhaço, probably as a result of headwater capture processes between the upper rio Paraná and rio Doce basins.
RESUMO
Hypostomus cochliodon group is a monophyletic clade of 20 valid species of Neotropical armored catfishes that is widely distributed throughout South America. Recently, specimens identified as H. cochliodon from the type locality and nearby localities were examined, and found to include representatives of more than one species. A redescription of H. cochliodon is provided, with a description of two new species, one from the Bodoquena Plateau and another from several localities of the rio Paraguay basin. A lectotype for H. cochliodon is designated herein, since the previous designation is invalid. Hypostomus cochliodon is diagnosed from all other species of the H. cochliodon group by having the opercle almost completely covered laterally by thick layer of skin, the absence of buccal papilla, weak to moderately developed keels on the lateral plates of the body and by the color pattern of its body and fins. Hypostomus basilisko, new species, is distinguished from the remaining species of the H. cochliodon group by the absence of spots on the body, highly developed keels and spoon-shaped teeth. Hypostomus khimaera, new species, is distinguished from the other species of the H. cochliodon group by having a dark tan stripe along the midline of the flank, black spots on the body and/or fins and teeth with mesial cusp and not spoon-shaped...
O grupo Hypostomus cochliodon é um clado monofilético com 20 espécies válidas de cascudos neotropicais que estão amplamente distribuídos por toda América do Sul. Recentemente, espécimes identificados como H. cochliodon da localidadetipo e regiões próximas foram examinados e descobriu-se que se tratavam de representantes de mais de uma espécie. Uma redescrição de H. cochliodon é apresentada, com a descrição de duas espécies novas, uma da Serra da Bodoquena e outra de várias localidades da bacia do rio Paraguai. Um lectótipo para H. cochliodon é aqui designado, já que a designação anterior é inválida. Hypostomus cochliodon é diagnosticado de todas as outras espécies do grupo H. cochliodon por possuir opérculo quase completamente coberto lateralmente por uma grossa camada de pele, ausência de papila bucal, placas laterais do corpo com quilhas fracas ou moderadamente desenvolvidas e pelo padrão de coloração de seu corpo e nadadeiras. Hypostomus basilisko, espécie nova, é distinguida das demais espécies do grupo H. cochliodon pela ausência de pintas no corpo, quilhas muito desenvolvidas e dentes em forma de colher. Hypostomus khimaera, espécie nova, é distinguida das outras espécies do grupo H. cochliodon por possuir uma faixa escura ao longo da linha mediana do corpo, pintas pretas no corpo e/ou nadadeiras e dentes com cúspide mesial não em forma de colher...
Assuntos
Animais , Classificação/métodos , Peixes/classificaçãoRESUMO
Hypostomus cochliodon group is a monophyletic clade of 20 valid species of Neotropical armored catfishes that is widely distributed throughout South America. Recently, specimens identified as H. cochliodon from the type locality and nearby localities were examined, and found to include representatives of more than one species. A redescription of H. cochliodon is provided, with a description of two new species, one from the Bodoquena Plateau and another from several localities of the rio Paraguay basin. A lectotype for H. cochliodon is designated herein, since the previous designation is invalid. Hypostomus cochliodon is diagnosed from all other species of the H. cochliodon group by having the opercle almost completely covered laterally by thick layer of skin, the absence of buccal papilla, weak to moderately developed keels on the lateral plates of the body and by the color pattern of its body and fins. Hypostomus basilisko, new species, is distinguished from the remaining species of the H. cochliodon group by the absence of spots on the body, highly developed keels and spoon-shaped teeth. Hypostomus khimaera, new species, is distinguished from the other species of the H. cochliodon group by having a dark tan stripe along the midline of the flank, black spots on the body and/or fins and teeth with mesial cusp and not spoon-shaped.(AU)
O grupo Hypostomus cochliodon é um clado monofilético com 20 espécies válidas de cascudos neotropicais que estão amplamente distribuídos por toda América do Sul. Recentemente, espécimes identificados como H. cochliodon da localidadetipo e regiões próximas foram examinados e descobriu-se que se tratavam de representantes de mais de uma espécie. Uma redescrição de H. cochliodon é apresentada, com a descrição de duas espécies novas, uma da Serra da Bodoquena e outra de várias localidades da bacia do rio Paraguai. Um lectótipo para H. cochliodon é aqui designado, já que a designação anterior é inválida. Hypostomus cochliodon é diagnosticado de todas as outras espécies do grupo H. cochliodon por possuir opérculo quase completamente coberto lateralmente por uma grossa camada de pele, ausência de papila bucal, placas laterais do corpo com quilhas fracas ou moderadamente desenvolvidas e pelo padrão de coloração de seu corpo e nadadeiras. Hypostomus basilisko, espécie nova, é distinguida das demais espécies do grupo H. cochliodon pela ausência de pintas no corpo, quilhas muito desenvolvidas e dentes em forma de colher. Hypostomus khimaera, espécie nova, é distinguida das outras espécies do grupo H. cochliodon por possuir uma faixa escura ao longo da linha mediana do corpo, pintas pretas no corpo e/ou nadadeiras e dentes com cúspide mesial não em forma de colher.(AU)