Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil.

The genus Rineloricaria comprises 69 valid species and has been considered monophyletic by some authors. The taxonomic history of Rineloricaria is quite complex, especially concerning its wide distribution and morphological plasticity that make it difficult to diagnose and describe new species. Even with the great species-richness of the genus and the huge diversity of the system, the Tocantins-Araguaia River basin hosts only three formally described species of Rineloricaria: R. hasemani, R. lanceolata, and R. osvaldoi, the former is known from lower Tocantins River, R. lanceolata widespread along Amazon basin and the last one restricts to the Araguaia River basin. Recent field expeditions and collection examination revealed an undescribed species of the genus from the upper and middle Tocantins River drainage. The new species is diagnosed among its congeners by having a greater number of premaxillary and dentary teeth (both with up to 15 vs. up to 10 in most congeners). From R. hasemani it is also distinguished by having the edge of snout straight in lateral view and absence of filaments on lower lip. It is also diagnosed from R. lanceolata by having wider cleithral width and a quite different color pattern, lacking a hyalin spot on the base of pectoral and pelvic fins; and from R. osvaldoi by having a lower head depth, triangular head in dorsal view, shorter snout length and other features.

A new species of driftwood catfish emCentromochlus/em Kner, 1858 (Siluriformes, Auchenipteridae, Centromochlinae) from Tocantins-Araguaia River drainage.

The genus Centromochlus includes eight catfish species in the Amazon and Orinoco river systems: C. schultzi from Xingu and Tocantins-Araguaia rivers; C. melanoleucus from Tapajós and Teles Pires rivers; C. macracanthus from Negro River; C. orca from Nhamundá River; C. heckelii and C. existimatus from Amazon and additionally at the Essequibo rivers; C. carolae and C. musaica from Orinoco River system. Recent field expeditions and collection examination revealed an undescribed species of Centromochlinae that has compatible features with Centromochlus. We herein describe a new species of Centromochlus from the Tocantins-Araguaia River drainage, diagnosed among most Centromochlinae by having a vermiculated color pattern on the dorsum and included in Centromochlus by sharing the derived features: ventrolateral position of eye socket; sphenotic notched for the exit of infraorbital canal; and posterior serrations along pectoral-fin spine numerous. The new species is diagnosed from congeners by having the pectoral-fin spine with dark bars, alternating with light bars (vs. pectoral-fin spine with light and uniform color in all Centromochlus); and it is further distinguished from its congeners (except C. carolae) by the ventral surface of head moderate to largely pigmented (vs. ventral surface of head unpigmented in C. heckelii, C. existimatus, C. orca, C. musaicus, C. schultzi, with few scattered dark chromatophores in C. macracanthus and C. melanoleucus; see diagnosis). A discussion about the systematics of the genus, plus the conservation status of the new species, and an identification key to species of Centromochlus, are also provided.

Pseudacanthicus major: description of one of the largest known Loricariidae (Hypostominae: Ancistrini), a species from rio Tocantins basin, Brazil.

The genus Pseudacanthicus currently comprises the following six species distributed in the Amazon and Tocantins basins, and coastal drainages from Guyana to French Guyana: P. serratus, P. fordii, P. histrix, P. spinosus, P. leopardus, P. pitanga, and P. pirarara. Herein we describe P. major, from rio Tocantins basin, one of the largest loricariid species known. The new species is distinguished from its congeners by the following combination of characters: having body color pattern with dark brown background without spots or blotches and dorsal and caudal fins with transversal white bands; anterior process of compound pterotic with no contacting with the posterior margin of the orbit and by the absence of a conspicuous crest on the posterior edge of parieto-supraocciptal. Other osteological characteristics are further used to diagnose P. major from others congeners. A discussion on gigantism and miniaturization in freshwater fish, ornamental fisheries activities, threats and conservation of the new species are also provided.

Redescription of Acanthicus hystrix Agassiz, 1829 (Siluriformes: Loricariidae), with comments on the systematics and distribution of the genus.

The genus Acanthicus is diagnosed from remaining Loricariidae genera by several characters, including the absence of adipose fin, pectoral-fin spine enlarged and the presence of small plates in abdomen region. Acanthicus currently comprises two valid species: A. hystrix and A. adonis. Acanthicus hystrix is distinguished from A. adonis, mostly by having body and fins dark brown to almost completely black background colored, without clear spots or dots (vs. dark brown color background with white spots covering body and fins) and presence of ochre to grey stripes in caudal fin (vs. stripes absent on caudal fin). The holotype of A. hystrix was destroyed during a bombing raid in the Second World War, no neotype was designed and the species is recognized by the illustration present in the original description, whose text is short, and uninformative. In the present contribution, specimens from several institutions were examined, revealing that the species is widespread in the Amazon, Tocantins-Araguaia and Orinoco basins, while A. adonis is restricted to the lower rio Tocantins. Herein, a redescription of Acanthicus hystrix is provided, with a comprehensive diagnosis of the genus and its species, along with a distribution map of the genus, a key to species identification, and brief comments on the systematics and distribution of the genus.

Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil.

The genus Pseudacanthicus comprises five valid species distributed in the Amazon, Guyana and Suriname basins: P. serratus, P. fordii, P. histrix, P. spinosus and P. leopardus. A new species of Pseudacanthicus from the Tocantins river basin is described. The new species is distinguished from its congeners by the following combination of characters: presence of dark blotches anostomosing to form continuous zigzag bands alongside longitudinal keels; absence of blotches on ventral surface of body; faint blotches on head; all fins with orange to red color on unbranched ray and sometimes on subsequent branched rays; and sphenotic and sixth infraorbital not in contact. Brief comments on the phylogeny of the genus, ornamental fisheries activities, threats and conservation of the new species are also provided.

Taxonomic revision of Spectracanthicus Nijssen & Isbrücker (Loricariidae: Hypostominae: Ancistrini), with description of three new species

A taxonomic review of Spectracanthicus Nijssen & Isbrücker, including Oligancistrus Rapp Py-Daniel, following a phylogenetic study, is presented. Additionally to S. punctatissimus (Steindachner) and S. murinus Nijssen & Isbrücker, three new species are recognized based on the examination of 159 specimens: S. immaculatus n. sp. from rio Tapajós basin, differs from its congeners by its color pattern consisting of a dark gray body, with no dots or spots, and by having very slender teeth; Spectracanthicus tocantinensis n. sp., from the rio Tocantins drainage is distinguished by the color pattern consisting of dark brown or black body with small, yellowish dots (except in S. punctatissimus), presence of thick teeth, infraorbital 4 forming most of the posterior edge of the orbit and the large basipterigium fenestrae; and Spectracanthicus zuanoni n. sp., from the rio Xingu basin is diagnosed by its color pattern consisting of large, white spots and by the larger orbital diameter. Other characters based on osteological features are also usefull to distinguish the species. A key to the species of the genus and a brief discussion of their threats and conservation are also provided. A revisão taxonômica de Spectracanthicus Nijssen & Isbrücker, incluindo Oligancistrus Rapp Py-Daniel, baseada em estudos filogenéticos recentes, é apresentada. Adicionalmente a S. punctatissimus (Steindachner) e S. murinus Nijssen & Isbrücker, três espécies novas são reconhecidas baseadas no exame de 159 espécimes: S. immaculatus, sp. n. proveniente da bacia do rio Tapajós, difere de suas congêneres pelo padrão de colorido do corpo cinza escuro sem pontos ou manchas e por possuir dentes bastante delgados; Spectracanthicus tocantinensis sp. n., da bacia do rio Tocantins pode ser distinguida pelo padrão de colorido do corpo marron escuro ou preto com pontos amarelados (exceto de S. punctatissimus), presença de dentes espessos, infraorbital 4 formando quase toda a margem posterior da órbita e pela presença de uma grande fenestra no basipterígio; e Spectracanthicus zuanoni sp. n., da bacia do rio Xingu é diagnosticada pelo padrão de colorido cinza escuro com grandes pontos brancos e por possuir maior diâmetro infraorbital. Outros caracteres osteológicos também podem ser utilizados para distinguir as espécies. Uma chave para as espécies do gênero e uma breve discussão sobre suas ameaças e conservação são também fornecidas.

Rineloricaria osvaldoi (Siluriformes: Loricariidae): a new species of armored catfish from rio Vermelho, Araguaia basin, Brazil

A new species of Rineloricaria Bleeker from the rio Vermelho, Araguaia basin, Goiás, Brazil is described. Rineloricaria osvaldoi, new species, can be distinguished from its congeners by the combination of the following characters: surface of thoracic area trapezoidal with greatest width between pectoral fins, up to 13 premaxillary teeth, largest body width at the section of the canal plate, anterior profile of the head of mature males semicircular in dorsal view. Although eight genera of Loricariinae are known from the rio Araguaia basin, R. lanceolata was only species of Rineloricaria previously reported from that basin. Therefore, the discovery of the R. osvaldoi increases the scenery of diversity of Loricariinae within this drainage basin.

Uma nova espécie de Rineloricaria Bleeker, proveniente do rio Vermelho, bacia do Araguaia, Goiás, Brasil, é descrita. Rineloricaria osvaldoi, espécie nova, distingue-se de suas congêneres pelos seguintes caracteres: superfície da região torácica trapezoidal com maior largura entre as nadadeiras peitorais, máximo de 13 dentes pré-maxilares, maior largura do corpo na seção da placa protadora de canal, perfil anterior da cabeça semicircular, em vista dorsal, em machos sexualmente maduros. A despeito de serem conhecidos oito gêneros de Loricariinae para a bacia do rio Araguaia, somente uma espécie de Rineloricaria era formalmente registradas para esta bacia, R. lanceolata. Deste modo, a descoberta de R. osvaldoi enriquece o cenário da diversidade de Loricariinae para esta bacia de drenagem.

A new species of Hemiancistrus from the rio Araguaia basin, Goiás state, Brazil (Siluriformes: Loricariidae)

Hemiancistrus cerrado is described from the tributaries of rio Araguaia, rio Tocantins basin. Hemiancistrus cerrado has external similarities with H. megalopteryx and H. punctulatus from coastal streams of southern Brazil, and can be distinguished by having a larger internarial width, 15.9-21.1 percent of head length (vs. 11.2-14.0 percent in H. megalopteryx and 11.2-13.9 percent in H. punctulatus) and, with little overlap, by the larger adipose-fin spine length, 9.4-13.6 percent of standard length (vs. 7.1-8.7 percent in H. megalopteryx and 7.4-10.0 percent in H. punctulatus). Hemiancistrus cerrado further differs from H. megalopteryx by having the pectoral-fin spine reaching maximally to the middle of the pelvic-fin spine when adpressed in adult males (vs. reaching tip). Hemiancistrus cerrado differs from other members of Hemiancistrus by color and numerous morphometric and meristic data.

Hemiancistrus cerrado é descrito de tributários da margem esquerda do rio Araguaia, bacia do rio Tocantins. Hemiancistrus cerrado possui similaridades externas com H. megalopteryx e H. punctulatus de drenagens costeiras do sul do Brasil, e pode ser separado das duas espécies pela maior distância entre as narinas, 15.9-21.1 por cento do comprimento da cabeça (vs. 11.2-14.0 por cento em H. megalopteryx e 11.2-13.9 por cento em H. punctulatus), e, com alguma sobreposição, pela maior nadadeira adiposa, 9.4-13.6 por cento do comprimento padrão (vs. 7.1-8.7 por cento em H. megalopteryx e 7.4-10.0 por cento em H. punctulatus); de H. megalopteryx ainda difere por espinho da nadadeira peitoral de machos adultos se estendendo até o meio do espinho da nadadeira pélvica quando adpressa (vs. se estendendo até a ponta do espinho). Hemiancistrus cerrado difere de outros congêneres pela coloração e diversos dados merísticos e morfométricos.

Ituglanis cahyensis, a new catfish from Bahia, Brazil (Siluriformes: Trichomycteridae)

A new trichomycterid catfish of the genus Ituglanis is described from the rio Palmares, a tributary of the rio Cahy in southeast Bahia State, Brazil. Ituglanis cahyensis is distinguished from all other congeners through a combination of characters, as the supraorbital laterosensory canal branch with pores s3 and s6 present, the low count of branched pectoral fin rays, and low number of paired ribs. It is further distinguished in proportional measurements, such as elongate nasal, maxillary, and rictal barbels, and small eye diameter.

É descrito um novo trichomycterídeo do gênero Ituglanis, capturado no rio Palmares, um tributário do rio Cahy, na costa sudeste do estado da Bahia, Brasil. Ituglanis cahyensis distingue-se das demais espécies congêneres por uma combinação de caracteres, como o canal laterosensorial supraorbital com os poros s3 e s6 presentes, um pequeno número de raios ramificados nas nadadeiras peitorais, e um pequeno número de costelas. Distingue-se ainda quanto a proporções morfométricas, como os barbilhões nasal, maxilar e rictal alongados, e o pequeno diâmetro ocular.