Two new species of Leporinus (Characiformes: Anostomidae) from the Brazilian Amazon, and redescription of Leporinus striatus Kner 1858.

Two new species of Leporinus are described from tributaries of the Rio Amazonas in Brazil. One species is known from the Jari and Tapajós River basins, and is identified on the basis of a gas bladder reduced in size, a dark midlateral stripe on the body, dark transverse bars on the dorsum, a subinferior mouth, three teeth on the premaxilla, four teeth on the dentary and 16 scale rows around the caudal peduncle. The second new species is known from the Tocantins, Xingu and Tapajós River basins, and is identified on the basis of three dark longitudinal stripes on the body, a subinferior mouth, three teeth on the premaxilla, four teeth on the dentary and 12 scale rows around the caudal peduncle. In addition, Leporinus striatus is redescribed based on type and additional specimens from the Río de La Plata, Amazonas, Orinoco, Atrato, Magdalena and Sinu River basins. Leporinus striatus is identified on the basis of four dark longitudinal stripes on the body, a subterminal mouth, three teeth on the premaxilla, four teeth on the dentary and 16 scale rows around the caudal peduncle.

Description of two new sympatric species of the genus Hisonotus Eigenmann and Eigenmann, 1889, from upper Rio Tapajós, Mato Grosso state, Brazil (Pisces: Ostariophysi: Loricariidae).

Two new species of the genus Hisonotus are described from the upper Rio Tapajós basin, Mato Grosso State, Brazil. They are small species, growing up to about 30.0 mm SL, having the scapular bridge wide and totally exposed or having a small median pair of arrector fossae, and the abdomen completely covered with large plates in adult specimens (about 23.0 mm SL). They are distinguished from their congeners by the following combination of characters: Hisonotus chromodontus has 20-40 reddish-brown tipped premaxillary teeth, and 15-38 on the dentary bones; 2324 plates on the longitudinal series; a prominent large dark brown lateral stripe extending from the tip of the snout to the caudal blotch; transversal dark brown bars very inconspicuous or absent. Hisonotus luteofrenatus has a moderate number (12-28) of hyaline or slightly yellow-tipped premaxillary teeth, and 9-26 on the dentary bones; 25-26 plates on the longitudinal series; a characteristic yellow line extending from the anterior part of each orbit, over the inferior nostril, both converging to the tip of the snout.

Description of two new sympatric species of the genus Hisonotus Eigenmann and Eigenmann, 1889, from upper Rio Tapajós, Mato Grosso state, Brazil (Pisces: Ostariophysi: Loricariidae)

Two new species of the genus Hisonotus are described from the upper Rio Tapajós basin, Mato Grosso State, Brazil. They are small species, growing up to about 30.0 mm SL, having the scapular bridge wide and totally exposed or having a small median pair of arrector fossae, and the abdomen completely covered with large plates in adult specimens (about 23.0 mm SL). They are distinguished from their congeners by the following combination of characters: Hisonotus chromodontus has 20-40 reddish-brown tipped premaxillary teeth, and 15-38 on the dentary bones; 2324 plates on the longitudinal series; a prominent large dark brown lateral stripe extending from the tip of the snout to the caudal blotch; transversal dark brown bars very inconspicuous or absent. Hisonotus luteofrenatus has a moderate number (12-28) of hyaline or slightly yellow-tipped premaxillary teeth, and 9-26 on the dentary bones; 25-26 plates on the longitudinal series; a characteristic yellow line extending from the anterior part of each orbit, over the inferior nostril, both converging to the tip of the snout.

Descrevem-se duas novas espécies de Hisonotus das cabeceiras do Rio Tapajós, Mato Grosso. São espécies de pequeno porte dentro do gênero, até cerca de 30 mm CP; os espécimes adultos possuem ponte escapular larga e totalmente exposta, ou deixando apenas um pequeno par de arrector fossae mediano, e abdome completamente coberto por placas grandes, em indivíduos adultos (acima de 23,0 mm CP). A combinação dos seguintes caracteres diferencia as novas espécies das demais do gênero. Hisonotus chromodontus n. sp. apresenta grande número de dentes de ponta castanho-avermelhada, 20-40 no pré-maxilar e 15-38 no dentário; 23-24 placas na série longitudinal; uma predominante listra lateral marrom-escura larga, que se estende da ponta do focinho, passando abaixo da órbita, até o fim do pedúnculo caudal; barras transversais ausentes ou muito inconspícuas. Hisonotus luteofrenatus n. sp. apresenta 12-28 dentes de ponta hialina ou levemente amarelada no pré-maxilar e 9-26 no dentário; 25-26 placas na série longitudinal; uma característica linha amarela estendendo-se da região anterior de cada órbita, passando na região inferior da narina e ambas convergindo para a ponta do focinho.

Parotocinclus planicauda, a new species of the subfamily Hypoptopomatinae from southeastern Brazil (Ostariophysi: Loricariidae).

Parotocinclus planicauda, a new species from a tributary of the Doce River drainage in Minas Gerais State, Brazil, is distinguished from all other species of the genus by the presence of a caudal peduncle almost quadrangular in cross section; the anterior position of the adipose fin, close to the dorsal fin insertion; and very small orbits. A key to the Parotocinclus species of eastern Brazilian coastal rivers south of the São Francisco River is provided.

Parotocinclus planicauda, a new species of the subfamily Hypoptopomatinae from Southeastern Brazil (Ostariophysi: Loricariidae)

Parotocinclus planicauda, a new species from a tributary of the Doce River drainage in Minas Gerais State, Brazil, is distinguished from all other species of the genus by the presence of a caudal peduncle almost quadrangular in cross section; the anterior position of the adipose fin, close to the dorsal fin insertion; and very small orbits. A key to the Parotocinclus species of eastern Brazilian coastal rivers south of the Säo Francisco River is provided