Osvaldo Takeshi Oyakawa

University of São Paulo | USP · Museum of Zoology

Spintherobolus papilliferus is an endangered characid endemic of the Atlantic Rainforest, known from sparse locations in the upper rio Tietê basin around the metropolitan area of São Paulo city, and from an affluent of rio Itapanhaú, a coastal stream in Bertioga, São Paulo State. In 2020, S. papilliferus was sampled from the rio Ribeira de Iguape b...

A new species of the rubbernose pleco genus Chaetostoma is described from the Maicuru and Seiko Rivers, a northern tributary of the lower Amazon River and a tributary of the lower Xingu River, respectively, both in Par State, Brazil. The new species is diagnosed from all congeners, except members of the Chaetostoma anale species group, by having an...

The trichomycterid catfish Listrura menezesi, new species, is described from a flooded area adjacent to Rio das Panelas, Rio São João basin, Cachoeiras de Macacu municipality, Rio de Janeiro State, Brazil. It represents a most valuable remnant of Atlantic Forest biome that still resists the devastation of Brazilian coastlands. Listrura menezesi can...

Characidium iaquira, a new species from the upper rio Juruena, rio Tapajós basin, Brazil, is described. The new species can be promptly distinguished from all congeners by having a unique v‐shaped dark mark lying along the caudal‐fin extension, in medium‐ and large‐sized specimens, and a remarkable iridescent green colouration in life. Characidium...

The Ichthyological Collection at MZUSP houses ca. 130,000 lots and more than 1,5 million fish specimens belonging to over 350 families, 1,800 genera, and 9,000 species. The vast majority of this material, 99.7%, is from the Neotropics, especially from Brazil, Peru, and Venezuela. This article recovers the history of the Ichthyological Collection of...

Two new species of the suckermouth armored catfish genus Baryancistrus are described from the Jari River basin, at the border of Pará and Amapá states, Brazil. The new species are the first representatives of the genus described from rivers draining the Guiana shield, and can be distinguished from their congeners by color pattern and a combination...

Three new species, of three different genera of loricariids, are described from the headwaters of Serra da Mantiqueira and Cadeia do Espinhaço, in Southeastern Minas Gerais State, Brazil. In this region, the Serra da Mantiqueira and the Complexo do Espinhaço are the highest points of the Brazilian Shield and delimits the headwaters of four drainage...

Ituglanis amphipotamus, new species, is distinguished from all congeners by the combination of the following characters: anterior cranial fontanel present, i,5 pectoral-fin rays, nasal canal and antorbital segment of infraorbital canal absent, five or six pairs of ribs, 39 post-Weberian vertebrae. It can be further distinguished from the sympatric...

Three new species of Harttia from the Rio Xingu basin in the region of Serra do Cachimbo, Pará State, Brazil, are described. Harttia rondoni n. sp., H. panara n. sp. and H. villasboas n. sp. were collected in the Rio Curuá, a tributary of Rio Iriri, Rio Xingu drainage. Harttia rondoni was additionally recorded from the Rio Fresco basin, a tributary...

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 roundis...

Most species of the genus Harttia inhabits the headwaters of small tributaries, but some species are restricted to the main channel of some rivers. This feature, combined with limited dispersal ability, leads to the formation of small isolated populations with reduced gene flow. Currently, there are 23 taxonomically defined and recognized species,...

A new species of Characidium is described based on specimens obtained from the highland streams of the Serra do Mar, Atlantic Forest Biome, in Paraná State, Southern Brazil. The new species is possibly a member member of the C. lauroi group, which is diagnosed by having the isthmus unscaled, bars poorly marked, and spots on sides of body, and is co...

In the present paper we describe a new species of Pareiorhina from Minas Gerais State, Brazil. The new species is distinguished from its congeners by a combination of the following characters: the dorsal surface of caudal peduncle strongly concave, 30 vertebrae, bicuspid teeth, a conspicuous cylindrical shaped papilla between the oral valve and pre...

A new species of Hyphessobrycon is described from a tributary of the upper Rio Tapajós, Amazon basin, Mato Grosso, Brazil. Its exuberant colour in life, with blue to purple body and red fins, is appreciated in the aquarium trade. Characters to diagnose the new species from all congeners are the presence of a single humeral blotch, absence of a dist...

We herein describe Characidium satoi, new species, only known from its type locality at Rio Curral das Éguas, a small tributary of Rio Abaeté, in the Rio São Francisco basin, Brazil. It can be distinguished from its congeners by the following characteristics: area between the pelvic fin and the origin of anal fin moderate to strongly convex in late...

This study aimed to survey the fish fauna of Cubatão River and its tributaries on the Atlantic Coast of São Paulo State, Brazil. For this study we captured the fishes in eight sampled sites: three in the Cubatão River itself (points 5, 6 and 7) and five in its tributaries, three on the left bank (1, 2 and 3) and two on the right bank (4 and 8) usin...

The Hoplias malabaricus species group represents one of the most complexes taxonomical problems in the systematics of Neotropical fishes, including specimens widely distributed in most drainages of South America and part of Central America with great variation or overlap of putative diagnostic characters. The large number of nominal species, many o...

The genus Spatuloricaria is diagnosed by a number of conspicuous characteristics that set it apart from other genera in the subfamily Loricariinae. The genus has a broad geographical distribution extending from Argentina to Panama. Despite the flood of new loricariid taxa described in the past decades, no new species of Spatuloricaria have been new...

A new species of Harttia, tribe Harttiini, is described from tributaries of upper portions of rio Paraná drainage. The new species, the smallest known species of the genus, attaining up to 74.0 mm of standard length, can be distinguished from its congeners by the combination of the following characters: abdomen completely covered by plates, a singl...

Lebiasina yepezi, a new Lebiasininae with a conspicuous color pattern, is described. The new species is endemic of the headwaters of the rio Negro, rio Branco, and rio Orinoco in the Serra Parima-Tapirapecó Mountains, at the border of Brazil and Venezuela. The new species is readily distinguished from all other Lebiasininae by the presence of four...

The fish species living in the freshwaters of the São Paulo state (393) are distributed among four major river basins: upper Paraná, Paraíba do Sul, Ribeira de Iguape and a set of small coastal drainages flowing directly into the Atlantic Ocean. Since these river basins drain areas with distinct vegetation types, soils, etc., each one has a differe...

The fish species living in the freshwaters of the São Paulo state (393) are distributed among four major river basins: upper Paraná, Paraíba do Sul, Ribeira de Iguape and a set of small coastal drainages flowing directly into the Atlantic Ocean. Since these river basins drain areas with distinct vegetation types, soils, etc., each one has a differe...

Pimelodus multicratifer, a new species, is described from the rio Ribeira de Iguape basin. The new species differs from the other Pimelodus species by the following features: 26 to 30 gill rakers on the first branchial arch; a combination of three to six rows of dark spots regularly or irregularly scattered on the flanks and several small dark spot...

Lebiasina yepezi, a new Lebiasininae with a conspicuous color pattern, is described. The new species is endemic of the headwaters of the rio Negro, rio Branco, and rio Orinoco in the Serra Parima-Tapirapecó Mountains, at the border of Brazil and Venezuela. The new species is readily distinguished from all other Lebiasininae by the presence of four...

Species occurrence and watershed matrix. Maps and additional data available at http://peixesraros.conservation.org.br. (0.74 MB XLS)

Background: Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priori...

The rediscovery of the enigmatic subterranean characiform Stygichthys typhlops is reported almost a half-century after the collection of the holotype, the only specimen previously known. Thirty-four specimens were collected in two shallow hand-dug wells at the region of the type locality, c. 13 km south-west of the town of Jaíba, Minas Gerais, Braz...

Hoplias lacerdae was originally described from the rio Ribeira de Iguape, Iporanga, São Paulo State. The Hoplias lacerdae group is defined as containing generally large trahiras with the medial margins of dentaries running parallel to each other and lacking teeth on the basihyal compared to the H. malabaricus group in which the medial margins of th...

A new species of the mailed catfish genus Harttia is described from the São Francisco River drainage, States of Minas Gerais and Bahia, Brazil. The new species is distinguished from congeners by the combination of an abdominal region covered by small bony plates, plates 3–4 times in eye diameter; interorbital width 3.1–4.0 in head length and greate...

Australoheros ribeirae, new species, described from the rio Ribeira do Iguape basin, southeastern Brazil, has a colour patter similar to several undescribed species of Rio de Janeiro Sate. However, it differs from them by having a truncate neural process of the 2 nd caudal vertebra. Australoheros ribeirae differs from the other valid species of the...

0603. A synthesis concerning fishes from Upper Paraná River basin is presented, based on data from fish-collections, literature, and new field samples. Three hundred and ten species, pertaining to 11 orders and 38 families, are referred to the drainage, elevating anterior estimates. Concerning total species, 236 (76.1%) are autochthonous, 67 (21.6%...

Two new Isbrueckerichthys species from Paranapanema river basin are described, I. saxicola and I. calvus, respectively from ribeirão Jacutinga and rio Taquara affluents. Both species present all diagnostic characters of the genus, and differ from their congeners by having bicuspid teeth (vs. simple teeth in I. alipionis), hypertrophied odontodes al...

A synthesis concerning fishes from Upper Paraná River basin is presented, based on data from fish-collections, literature, and new field samples. Three hundred and ten species, pertaining to 11 orders and 38 families, are referred to the drainage, elevating anterior estimates. Concerning total species, 236 (76.1%) are autochthonous, 67 (21.6%) are...

The taxonomy of the nominal species of giant trahiras Hoplias aimara (Valenciennes, 1846) and Hoplias macrophthalmus (Pellegrin, 1907), both described from Cayenne (French Guiana), was evaluated to determine whether they constitute distinct forms and to determine the geographic distribution of the recognized species. A total of 200 specimens were e...

The genus Pseudotocinclus is revised and two new species are described: Pseudotocinclus juquiae from the Ribeira de Iguape basin and Pseudotocinclus parahybae from the rio Paraíba do Sul basin. The presence of a small naked area on the snout tip distinguishes P. tietensis from P. parahybae and P. juquiae, which have the snout tip covered with small...

Two new species of the trichomycterid catfish genus Trichomycterus from the rio Ribeira de Iguape basin, southeastern Brazil, are described. Trichomycterus tupinamba differs from the other species of the Trichomycterinae in having the first pectoral-fin ray not prolonged as a filament, the caudal fin is truncate with attenuated edges, two paired su...

Species of the loricariid genus Hypostomus Lacépède, 1803 from rio Ribeira de Iguape drainage (São Paulo and Paraná States, Brazil) are reviewed. Four species were found in the area: H. agna (Miranda-Ribeiro, 1907), H. ancistroides (Ihering, 1911), H. interruptus (Miranda-Ribeiro, 1918), and a new species H. tapijara. Hypostomus tapijara is disting...

Isbrueckerichthys epakmos, new species, is described from the tributaries of the rio Juquiá, rio Ribeira de Iguape basin, São 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 fo...

Characid genera listed below as Incertae Sedis constitute a largely heterogeneous assemblage of small to large-sized fishes. Most of these genera had been included in the subfamily Tetragonopterinae (see Géry, 1977). However, considering the lack of evidence that this subfamily constitutes a monophyletic assemblage (e.g., Weitzman & Fink, 1983; Wei...

We studied spatial and temporal patterns in fish species composition and diversity at the upper Juru River located in the west Brazilian Amazon. We collected with gillnet 822 fishes belonging to 90 species in the main Juru River, its tributaries and the floodplain lakes during wet and dry seasons. Fish abundance and species richness were greater in...

The fishing and hunting performed by inhabitants of the Extractive Reserve of the Upper Juru, Acre, Brazil was studied, and an ecological analysis on the use of fish and game, including preferences, taboos and medicinal uses, and of fish abundance was made. Research was carried out at the Upper Juru Extractive Reserve in three visits (1993 and 1994...

As relações filogenéticas entre os gêneros das famílias Erythrinidae e Lebiasinidae foram analisadas utilizando-se o método cladístico, com base em 108 caracteres morfológicos. A análise feita com o auxílio do programa Hennig86 encontrou duasárvores mais parcimoniosas de relações com 213 passos, índice de consistência (IC) e índice de retenção (IR)...