Siluriformes: Loricariidae) from the Rio Paraguay Basin, with a Redescription of Hypostomus Cochliodon Kner, 1854
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Neotropical Ichthyology, 12(3): 585-602, 2014 Copyright © 2014 Sociedade Brasileira de Ictiologia DOI: 10.1590/1982-0224-20130162 Two new species of the Hypostomus cochliodon group (Siluriformes: Loricariidae) from the rio Paraguay basin, with a redescription of Hypostomus cochliodon Kner, 1854 Luiz F. C. Tencatt1, Cláudio H. Zawadzki2 and Otávio Froehlich3 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 localidade- tipo 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. Key words: Armored catfish, Hypostominae, Neotropical fishes, rio Cuiabá, Taxonomy. Introduction Eigenmann, comprises the only species of fishes with a diet consisting predominantly of wood (Schaefer & Stewart, 1993; The Hypostomus cochliodon group is a monophyletic clade Nelson et al., 1999). The H. cochliodon group includes 20 valid (Montoya Burgos et al., 2002; Weber & Montoya Burgos, 2002; nominal species (Hollanda Carvalho et al., 2010) that are widely Armbruster, 2003, 2004; Armbruster & de Souza, 2005), of distributed throughout South America (Armbruster, 2003; armored catfishes that, together with Panaque Eigenmann & Hollanda Carvalho & Weber, 2004; Armbruster & de Souza, 1Universidade Estadual de Maringá, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais. Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil. [email protected] 2Universidade Estadual de Maringá, Departamento de Biologia/ Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia). Av. Colombo, 5790, Nupélia G90, 87020-900 Maringá, PR, Brazil. [email protected] 3Universidade Federal de Mato Grosso do Sul, Laboratório de Zoologia/Centro de Ciências Biológicas e da Saúde. Caixa Postal 549, 79070- 900 Campo Grande, MS, Brazil. [email protected] 585 586 Two new species of the Hypostomus and redescription of Hypostomus cochliodon 2005). Armbruster (2004) discovered three synapomorphies of from the rio Paraguay basin. Armbruster (2003) and Hollanda the H. cochliodon group, the loss of a notch between the Carvalho & Weber (2004) suggested that H. cochliodon from metapterygoid and hyomadibula, strongly angled dentaries and the rio Paraguay basin is likely a complex of species. spoon-shaped teeth, although the last character is not present From the examination of several recent collected specimens in all members of the group (Armbruster, 2003, 2004). Taxonomic from the rios Paraná and Paraguay basins it was possible to studies for this group have been frequent (e.g., Armbruster, confirm that more than one species of the Hypostomus 2003; Hollanda Carvalho & Weber, 2004; Armbruster & de cochliodon group coexist not only in the rio Cuiabá (the type Souza, 2005; Hollanda Carvalho et al., 2010) but most of them locality of H. cochliodon), but also in other regions of the rio were mainly focused on the Amazonian representatives. Paraguay basin. From the analysis of fish from several localities Hypostomus cochliodon Kner was described from the rio within the rio Paraguay basin, specimens having a dark tan Cuiabá basin, based on five syntypes collected by Natterer. stripe mentioned by Armbruster (2003) were revealed to be a Armbruster (2003) reported that Hypostomus cochliodon was new species, which is described herein. found exclusively in the rio Paraguay basin, but Weber (2003) Additionally, specimens from the Bodoquena Plateau, noted that its distribution included the middle rio Paraná basin. Mato Grosso do Sul State, Brazil, revealed another More recently, H. cochliodon was also reported from the upper undescribed species of the Hypostomus cochliodon group, rio Paraná basin, due to flooding of the Sete Quedas falls after whose description is also presented herein. The redescription the construction of the Itaipu reservoir (Zawadzki et al., 2005; of Hypostomus cochliodon with the designation of a lectotype Graça & Pavanelli, 2007). is also provided. In the original description, Kner (1854) described the color pattern of Hypostomus cochliodon based on his observations Material and Methods of the syntypes and remarks in Natterer’s field notes. The author noted a concentration of small black spots on the dorsal portion Measurements were made with digital calipers to the nearest of the head, which are scarce along the trunk. Kner (1854) also 0.1 mm. Methodology and terminology for measurements mentioned the presence of black spots on the fins as well as the follow Boeseman (1968) with modifications of Weber (1985) bicolored pattern of the fins, which present their proximal basis and Zawadzki et al. (2008). Plate counts and nomenclature at the same color as the body and distal tips darker. Armbruster follow Schaefer (1997), with the modifications of Oyakawa et (2003) performed a comprehensive taxonomic review of the H. al. (2005). Standard length (SL) is expressed in millimeters and cochliodon group, providing redescriptions of the previously all other measurements are expressed as percentages of described species and describing four new species. In the same standard length or head length (HL). Vertebral and rib counts paper, Armbruster stated that H. cochliodon possesses color were taken from cleared-and-stained (c&s) specimens prepared pattern of the body generally entirely dark brown, with a dark according to Taylor & Van Dyke (1985). The vertebral complex tan stripe in the midline of the flank; stripe sometimes crossed of the Weberian apparatus and the compound caudal centra by dark saddles or with dark spots anteriorly. Hollanda Carvalho are each counted as a single element. Syntypes of Hypostomus & Weber (2004) raised some issues in the redescription of H. cochliodon, NMW 46277 and NMW 59395, were examined cochliodon made by Armbruster (2003). Initially, there was a through high definition photographs. In the species contradiction in color patterns described by Armbruster (2003) descriptions numbers indicated by an asterisk refer to counts versus those mentioned in the original description by Kner of primary types. Institutional abbreviations are: AMNH, (1854), mainly by the presence of a dark tan stripe in the midline American Museum of Natural History, New York; ANSP, of the flank in H. cochliodon, reported by Armbruster (2003) Academy of Natural Sciences of Drexel University, Philadelphia; but which was not mentioned in Kner’s description. BMNH, The Natural History Museum, London; CPUFMT, Other point in Armbruster’s (2003) paper commented by Coleção de Peixes da Universidade Federal do Mato Grosso, Hollanda Carvalho & Weber (2004) were the diagnostic Cuiabá; INPA, Instituto Nacional de Pesquisas da Amazônia, characters, which have very large variation, such as the number Manaus; LBP, Laboratório de Biologia e Genética de Peixes, of teeth ranging from 6 to 27. In Kner’s (1854) description, the Universidade Estadual Paulista “Júlio de Mesquita Filho”, number of teeth ranged from seven to eight. Hollanda Carvalho Botucatu; MCP, Museu de Ciências e Tecnologia da Pontifícia & Weber (2004)