Edson H. L. Pereira

Three New Species of the Loricariid Catfish Genus Loricariichthys (Teleostei: Siluriformes) from Southern South America

Abstract Sixteen species of Loricariichthys Bleeker, 1862 are currently recognized in South America, four of which inhabit the continent portions south of the Amazon basin: Loricariichthys anus (Valenciennes, 1836) from lower río Paraná, rio Uruguai, and coastal streams in southern Brazil; Loricariichthys castaneus (Castelnau, 1855) from coastal streams of southeastern Brazil; Loricariichthys labialis (Boulenger, 1895) from río Paraguay and lower río Parana; and Loricariichthys platymetopon Isbrücker and Nijssen, 1979, from Río de la Plata basin. Three additional new species are described from this region, Loricariichthys edentatus n. sp. from the Province of Entre Rios, Argentina, Loricariichthys melanocheilus n. sp. from the rio Uruguai basin, and Loricariichthys rostratus n. sp. from the Itaipu Hydroelectric reservoir, in the río Paraná. Loricariichthys edentatus n. sp. has no teeth on the premaxilla, a feature unique in the genus. The monophyly of the genus Loricariichthys is discussed and it is provisionally diagnosed by having (1) the third infrapharyngobranchial with a triangular lateral flange; (2) ventral shelf of the antero- and posterohyal tall, deflected posteriorly so that it nearly forms a 180° angle with the main bodies of the bones; (3) the upper lip coalesced with the premaxillary region medially, never having barbel-like fringes along the transverse, medial portion and (4) the lower lip of immature males and females formed by two thick, cushionlike structures. Loricariichthys spixii (Steindachner, 1881) is regarded as a junior synonym of L. castaneus. Dezessies espécies de Loricariichthys Bleeker, 1862 são atualmente reconhecidas na América do Sul, quatro das quais habitam as porções do continente ao sul da bacia Amazônica: Loricariichthys anus (Valenciennes, 1836) do baixo rio Paraná, rio Uruguai e bacias costeiras do sul do Brasil; Loricariichthys castaneus (Castelnau, 1855) das bacias costeiras do sudeste do Brasil; Loricariichthys labialis (Boulenger, 1895) do rio Paraguai e baixo rio Paraná; e Loricariichthys platymetopon Isbrücker and Nijssen (1979) do rio Paraná, rio Paraguai e rio Uruguai. Três novas espécies são descritas desta mesma região: Loricariichthys edentatus sp. n. da Provincia de Entre Rios, Argentina; Loricariichthys melanocheilus sp. n. da bacia do rio Uruguai; e Loricariichthys rostratus sp. n. da região do lago da Usina Hidroelétrica de Itaipu, no rio Paraná. Loricariichthys edentatus sp. n. não apresenta dentes no premaxilar, um caráter único neste gênero. O monofiletismo de Loricariichthys é discutido, sendo o gênero diagnosticado provisoriamente por apresentar: (1) o terceiro infrafaringobranquial com uma lâmina lateral triangular; (2) lâminas ventrais dos cerato-hial anterior e posterior altas, defletidas posteriormente para quase formar um ângulo de 180° com o corpo principal dos óssos; (3) o lábio superior coalescido com a região do premaxilar medialmente, nunca possuindo franjas ou barbelas ao longo da porção medio-transversal; e (5) o lábio inferior de machos imaturos e fêmeas formado por duas estruturas grossas e arredondadas. Loricariichthys spixii (Steindachner, 1881) é considerado sinônimo júnior de L. castaneus.

A new species of sexually dimorphic Pareiorhaphis Miranda Ribeiro, 1918 (Siluriformes: Loricariidae) from the rio Doce basin, Brazil

Pareiorhaphis nasuta, a new neoplecostomine catfish of the family Loricariidae is described. The species was collected from headwaters of the rio Matipo, tributary of the upper rio Doce basin in State of Minas Gerais, Brazil. The new species is readily diagnosed from all remaining congeners by the longer snout and by the smaller orbital diameter. The new species is the first representative of the genus Pareiorhaphis discovered in the rio Doce basin, thus expanding its geographic distribution. A phylogenetic diagnosis for Pareiorhaphis is presented. Pareiorhaphis nasuta, um novo cascudo neoplecostomineo da familia Loricariidae e descrito. Os exemplares foram capturados nas cabeceiras do rio Matipo, tributario do rio Doce no Estado de Minas Gerais, Brasil. A nova especie e facilmente diagnosticada entre todos os demais congeneres pelo maior comprimento do focinho e pelo menor diâmetro orbital. Esta nova especie representa o primeiro registro do genero Pareiorhaphis na bacia do rio Doce, expandindo a sua distribuicao geografica. Uma diagnose filogenetica e apresentada para Pareiorhaphis.

Resurrection of Pareiorhaphis Miranda Ribeiro, 1918 (Teleostei: Siluriformes: Loricariidae), and description of a new species from the rio Iguaçu basin, Brazil

A new species of the loricariid subfamily Neoplecostominae is described on the basis of specimens obtained from the headwaters of the rio Iguacu basin in the State of Parana, southern Brazil. Pareiorhaphis parmula is the first representative of the genus discovered from the rio Parana basin and expands the geographic distribution of the genus. It is diagnosed from other Pareiorhaphis species by having one small plate on each side of the pectoral girdle, just posterior to the gill opening and the club-shaped pectoral-fin spine, broadening from base to tip in adult males. All species formerly included in Hemipsilichthys except H. gobio, H. papillatus, and H. nimius are transferred to the genus Pareiorhaphis, which is resurrected from the synonymy of Hemipsilichthys.

Isbrueckerichthys epakmos, a new species of loricariid catfish from the rio Ribeira de Iguape basin, Brazil (Teleostei: Siluriformes)

Isbrueckerichthys epakmos, new species, is described from the tributaries of the rio Juquia, rio Ribeira de Iguape basin, Sao Paulo State, Brazil. The new species displays a unique sexual dimorphism. Mature males are distinguished from its congeners by having a well-developed soft fleshy area and a clump of hypertrophied short odontodes directed forward or slightly upward on anterior portion of snout. It is compared with I. duseni and I. alipionis, which occurs sympatrically in the rio Ribeira de Iguape drainage. A key to the species of Isbrueckerichthys is provided.

Pareiorhaphis scutula, a new species of neoplecostomine catfish (Siluriformes: Loricariidae) from the upper rio Doce basin, Southeastern Brazil

Pareiorhaphis scutula, new species, is described from the headwaters of the rio Piracicaba, tributary to the upper rio Doce basin in the State of Minas Gerais, southeastern Brazil. The new species is distinguished from all congeners by having an unique autapomorphic feature: the abdominal surface from pectoral girdle to pelvic-fin insertions covered with small platelets imbedded in skin and irregularly scattered. This feature is not shared with any other Pareirhaphis species. Pareiorhaphis scutula is further compared with the sympatric P. nasuta.

A New Species of Hisonotus (Siluriformes: Loricariidae: Hypoptopomatinae) from the Laguna dos Patos Basin, Southern Brazil

Abstract Hisonotus armatus, a new hypoptopomatine species, is described from the Laguna dos Patos basin, Rio Grande do Sul State, southern Brazil. The new species is distinguished from other Hisonotus species by aspects of the morphology of the rostral plate, the arrangement of abdominal plates, and the caudal-fin color pattern. Hisonotus armatus, nova espécie de hipoptopomatíneo, é descrita do sistema da laguna dos Patos, Rio Grande do Sul, sul do Brasil. A nova espécie se diferencia das demais do gênero Hisonotus pela morfologia da placa rostral, pelo arranjo das placas abdominais, e pelo padrão de colorido da nadadeira caudal.

A New Genus and Species of Hypoptopomatine Catfish (Siluriformes: Loricariidae) from the Upper Rio São Francisco Basin, Brazil

Plesioptopoma curvidens is a new genus and species of hypoptopomatine loricariid from the upper Rio Paraopeba, a tributary to the Rio São Francisco in southeastern Brazil. Plesioptopoma is attributed to the hypoptopomatines based on five shared synapomorphies, and differs from all remaining members of the subfamily by having the premaxilla and dentary tooth series strongly curved mesially, in such a way that the mesial portion of the tooth series in both sides are turned and run parallel to each other, the caudal peduncle distinctly quadrangular in cross-section, and the anterior margin of the snout devoid of dermal plates.

A New Genus and Species of a Minute Suckermouth Armored Catfish (Siluriformes: Loricariidae) from the Rio Tocantins Drainage, Central Brazil: The Smallest Known Loricariid Catfish

Nannoplecostomus eleonorae, a new genus and species of a miniature suckermouth armored catfish, is described based on specimens collected from the karst region of São Domingos, upper Rio Tocantins basin, Goiás State, central Brazil. The new genus and species can be diagnosed among loricariids by presenting a unique reductive pattern of lateral dermal plates, with most of the body covered by only three series of plates (viz., dorsal, mid-ventral, and ventral). Based on the available published phylogenetic studies for the family, we provisionally consider Nannoplecostomus eleonorae as being an incertae sedis taxon within Loricariidae. Achieving a maximum standard length of 22.2 mm SL, Nannoplecostomus eleonorae is the smallest known loricariid catfish, and a list of the remaining smallest loricariids is provided. É descrito um novo gênero e espécie de cascudo miniaturizado, Nannoplecostomus eleonorae, baseado em espécimes coletados na região de carste de São Domingos, bacia do alto rio Tocantins, estado de Goiás, Brasil central. O novo gênero e espécie pode ser diagnosticado dos demais loricarídeos por apresentar um padrão de redução das placas dérmicas laterais único, em que a maior parte do corpo é recoberta por apenas três séries de placas (viz., séries dorsal, médio-ventral e ventral). Baseado nos estudos filogenéticos publicados para a família, consideramos Nannoplecostomus eleonorae como sendo um táxon incertae sedis dentro de Loricariidae. Atingindo um comprimento padrão máximo de 22,2 mm CP, Nannoplecostomus eleonorae é o menor loricarídeo conhecido, e uma lista dos demais menores loricarídeos é fornecida.

Alterações histológicas em placas ósseas do peixe cascudo Rineloricaria strigilata (Hensel) (Teleostei, Loricariidae) e sua freqüência no lago Guaíba, Rio Grande do Sul, Brasil

Little information is available about natural populations of fishes exposed to polluted waters in Brazil. Contaminants may be lethal or predispose fishes to sickness, being the analysis of aquatic organisms a good indicator of environmental quality. The violinha, Rineloricaria strigilata (Hensel, 1868), is a common loricariid catfish in the Guaiba lake basin, Rio Grande do Sul, Brazil, and has been selected as a bioindicator for being resident, occurring in more than 50% of the samples, and by showing externally detectable neoplasies. These are characterized by its dark pigmentation, bony plates hypertrophy, and hypertrophy and irregular arrangement of the odontodes. Histology showed hypertrophied epitelial tissues, with an increased number of secretory cells, blood cells, and melanina pigments, giving the dark appearance to the neoplasm. Observed frequencies of neoplasm were higher in lake Guaiba than in comparativo samples. Inside lake Guaiba, a pattern of distribution of neoplasm was observed, with the absence of neoplasm in fishes at the collected site that receives water from rio Jacui, and frequencies of 3.04 to 16.81% in the collection localities in front of Porto Alegre and downstream localities, that receive water from rio Jacui, rio dos Sinos and rio Gravatai, that drain urban and industrial area of Porto Alegre and neighborhood cities.

A New Species of the Hypoptopomatinae Catfish Parotocinclus (Siluriformes: Loricariidae), from the Headwaters of the Rio Jequitinhonha, Brazil

A new species of the hypoptopomatine loricariid genus Parotocinclus is described based on material from the headwaters of the Rio Jequitinhonha, Minas Gerais State, eastern Brazil. The new species is distinguished from all congeners, except P. prata and P. robustus, by the absence of abdominal plates between the pectoral girdle and the anus. It differs from P. prata and P. robustus by having a smaller cleithral width (16.7–20.7 vs. 20.8–27.6% SL in P. prata and 25.9–28.8% SL in P. robustus) in addition to other morphological features. Uma nova espécie de loricarídeo hypoptomatíneo do gênero Parotocinclus é descrita com base em material das cabeceiras do Rio Jequitinhonha, no estado de Minas Gerais, leste do Brasil. A nova espécie é diferenciada de todos os seus congêneres, exceto P. prata e P. robustus, pela ausência de placas no abdômen entre a cintura peitoral e o ânus. Se distingue das espécies acima pela menor largura cleitral (16.7–20.7 vs. 20.8–27.6% do Comprimento Padrão em P. prata e 25.9–28.8% do Comprimento Padrão em P. robustus), além de outros caracteres morfológicos.