Taxonomic Inventory of Anostomids (Pisces, Anostomidae) of the Uatumã River Basin, Amazonas State, Brazil, with Description of Two New Species.

This study concerns in taxonomic survey on the anostomid species of the Uatuma River. It includes redescriptions and illustrations of all species found at the area The utilized material cames from an intensive fish survey program carried out at the Uatumã River drainage, in the area affected by the Balbina and Pitinga hydroelectric dams, boths in the Amazonas state. It is deposited at the icththyological collection of the Instituto Nacional de Pesquisas da Amazonia (INPA). Twenty two anostomid species were found in the Uatumã River drainage, belonging to eight genera, of which Leporinuswere dominant, with twelve species, followed by Laemolyta, Anostomus, Anostomoidesand Pseudanos(with two species) and Schizodon, Anostomoides, Synaptolaemusand Gnathodolus,with one species. Two species, Leporinus uatumaensisn.sp. and Leporinus pitingain.sp. are considered new for science and here described. Diagnostic characters, distribution and habitat are cited; major ontogenetic changes in color patterns are also discussed. Several species had their distribution expanded.O presente estudo trata do inventário, descrição e ilustração das espécies de anostomídeos da bacia do rio Uatumã. Ele foi desenvolvido com base na coleção de peixes do INPA, montada a partir de um intenso programa de coletas, na bacia do Uatumã, nas áreas de influência das usinas hidrelétricas de Balbina e Pitinga, ambas no estado do Amazonas. Para a maioria das espécies são feitos comentários sobre os caracteres diagnósticos, área de distribuição, biótopos preferenciais e principais variações do padrão de colorido entre adultos e jovens. As vinte e duas espécies identificadas pertencem a 8 gêneros, sendo Leporinusdominante, com 12 espécies, seguido de Laemolyta, Anostomuse Pseudanos,com duas e de Schizodon, Anostomoides, Synaptolaemuse Gnathodolus,com uma espécie cada. Dentre os peixes inventariados, duas espécies são consideradas novas e descritas (Leporinus uatumaensissp.n e Leporinus pitingaisp.n.) A partir deste estudo, as espécies tiveram sua área de ocorrência ampliada, já que algumas delas só haviam sido assinaladas para a localidade-tipo

A new species of Serrasalmus (Teleostei: Characidae: Serrasalminae), S. altispinis, is described from Uatumã basin (Amazonas, Brazil), with a complementary description of S. rhombeus (Linnaeus, 1766) from the Guiana shield

Serrasalmus rhombeus (Linnaeus, 1766), described from Surinam, is recorded from the Amazon, the Orinoco and the Guiana coastal basins. Cited from the Maroni to the Iracoubo basins in French Guiana, S. rhombeus is recorded from the Araguari basin (Amapâ, Brazil). In the Uatumã basin (Amazonas, Brazil), S. rhombeus is sympatric with a new species, Serrasalmus altispinis. The body of S. altispinis is lightly more compressed and deeper than in S. rhombeus. S. altispinis is mainly characterized by the presence of 4 supraneurals (vs. 5 in S. rhombeus) and deeper serrae. These characteristics are shared with S. altuvei, S. compressas and S. geryi, three species of piranhas with a deep and compressed body, but different from S. altispinis

A new silver dollar species of Metynnis cope, 1878 (Characiformes: Serrasalmidae) from Northwestern Brazil and Southern Venezuela

A new Metynnis is described from the rio Negro in Brazil and Venezuela, and from black- or clearwater tributaries in Brazil including the rios Parauari, Uatumã, Trombetas, and Sucunduri (the latter belonging to the rio Madeira basin). The new species can be distinguished readily from all congeners by having a high concentration of dark chromatophores on the lateral line scales. It can be further distinguished by the combination of head length 24.3-27.5% of SL, 13-18 gill-rakers on upper limb and 16-24 gill-rakers on lower limb. The new species is most similar to and likely most closely related to Metynnis hypsauchen. These two species share a similar color pattern, body shape and sexual dimorphism of the anal fin. However, they differ in that M. hypsauchen has a lightly pigmented lateral line. The new species is also distinguished from M. hypsauchen by having 56-65 predorsal scales and 90-104 lateral line scales (vs. 36-54, and 65-82, respectively). A detailed osteological description of the new species is provided. © 2016, Sociedade Brasileira de Ictiologia. All rights reserved

Redescription and geographical distribution of the endangered fish ossubtus xinguense Jégu 1992 (Characiformes, Serrasalmidae) with comments on conservation of the rheophilic fauna of the Xingu River

The monotypic species Ossubtus xinguense was originally described based on scarce material putatively divided into juveniles and adults. Ossubtus xinguense has a restricted distribution and was previously known only from a few rapids downstream of the city of Altamira, in the Volta Grande stretch of the Middle Xingu River. Until recently, the species was rare in museums because its habitat (large rapids) is difficult to sample. Large-scale collecting efforts targeting rapids throughout the Xingu River basin have yielded an abundance of new material. Based on an analysis of the type series and freshly preserved specimens, we redescribe O. xinguense and provide detailed osteological descriptions along with comments about its relationships within Serrasalmidae. Furthermore, we expand the geographical distribution of the species and discuss its conservation status. © 2016 Andrade et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Amphistomes as species markers of the serrasalmid fish, Myleus ternetzi (NORMAN), from French Guiana, with descriptions of two new species and one new genus

Two new species of amphistome (Trematoda) are described from "pacu", Myleus ternetzi, from French Guiana. For one of these, a new genus is proposed. Additionally, a common species, Pseudocladorchis cylindricus, is reported. Pacudistoma guianensis sp. nov. is a robust form with a massive pharynx; a large genital sucker; long, convoluted ceca; and a subterminal acetabulum that is smaller than the genital sucker. Myleustrema concavatum gen. et sp. nov., on the other hand, has a slender, flattened body, concave dorsally; a small pharynx; no genital sucker; ceca that are short, slender, and nearly straight; and a small, terminal acetabulum which is provided with papillae. The two new forms seem to be highly host specific and could therefore be used as biological markers

New amphistome (Trematoda) genera and species from Amazonian serrasalmid fishes, Myleus (Myloplus)

Two new genera and three new species of amphistome trematodes (Cladorchiidae) are described from Amazonian serrasalmid fish. These species appear to be characteristically found in the subgenus Myleus (Myloplus) since they are nearly always found together in the three species in this subgenus (rubripinnis, asterias and an undescribed species). They have not been found in four other species of Myleus caught in the same localities. The new genera and species are: Inpamphistoma papillatum gen. et sp. n., Annelamphistoma elegans gen. et sp. n. and Dadayius pacuensis sp. n. The two new genera have ventral surfaces that are convex and covered with papillae which would appear to separate them from all other known genera among the amphistomes. They differ from each other by body shape and the number of muscular puckers in the body wall. Inpamphistoma is flattened, strongly concave dorsally and has one pair of muscular puckers. Annelamphistoma, on the other hand, is only slightly concave dorsally and is provided with five pairs of puckers. SEM studies showed that the ventral papillae are domed to conical and are neither cililated nor branched. Additionally, circles of domed papillae with pores are found around the mouth of Inpamphistoma. Dadayius pacuensis sp. nov. has the transverse tegumental folds in the botto mof the acetabular cavity that characterize the genus. The new species has a massive acelabulum which serves to distinguish it from the type and only species. It also differs from the type in being only one-half as large. The three amphistomes described here were found together in nearly every adult specimen of fish belonging to Myleus (Myloplus) and are as widely distributed geographically as their hosts