Navegando por Assunto "Characiformes"

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Acesso aberto (Open Access)
Genetic differentiation in the populations of red piranha, Pygocentrus nattereri Kner (1860) (Characiformes: Serrasalminae), from the river basins of northeastern Brazil
(Universidade Federal do Pará, 2015-11) LUZ, Luciana Alves da; REIS, Luana da Luz dos; SAMPAIO, Maria Iracilda da Cunha; BARROS, Maria Claudene; FRAGA, Elmary da Costa
The red piranha, Pygocentrus nattereri, is an important resource for artisanal and commercial fisheries. The present study determines the genetic differentiation among P. nattereri populations from the northeastern Brazilian state of Maranhão. The DNA was isolated using a standard phenol-chloroform protocol and the Control Region was amplified by PCR. The PCR products were sequenced using the didesoxyterminal method. A sequence of 1039 bps was obtained from the Control Region of 60 specimens, which presented 33 polymorphic sites, 41 haplotypes, һ =0.978 and π =0.009. The neutrality tests (D and Fs) were significant (P < 0.05) for most of the populations analyzed. The AMOVA indicated that most of the molecular variation (72%) arises between groups. The fixation index was highly significant (FST = 0.707, P < 0.00001). The phylogenetic analyses indicated that the specimens represented a monophyletic group. Genetic distances between populations varied from 0.8% to 1.9%, and were <0.5% within populations. The degree of genetic differentiation found among the stocks of P. nattereri indicates the need for the development of independent management plans for the different river basins in order to preserve the genetic variability of their populations.
Acesso aberto (Open Access)
A new miniature of Xenurobryconini (Characiformes: Characidae) from the rio Tapajós basin, Brazil
(Universidade Federal do Pará, 2016) MENDONÇA, Marina Barreira; PEIXOTO, Luiz Antônio Wanderley; DUTRA, Guilherme Moreira; NETTO-FERREIRA, André Luiz
A new species of Xenurobrycon isdescribed from tributaries of the rio Tapajós, Pará, Brazil. It is diagnosed from all congeners by the dark color of the posterior half of both caudal-fin lobes, the presence of infraorbitals one, two, and three, the presence of a set of lamellar processes on eighth principal caudal-fin ray of mature males, the presence of bony hooks similar in size or decreasing posteriorly on last unbranched and first 9-12 branched anal-fin rays of mature males, the presence of only conical teeth on both jaws, the lack of the adipose fin and the presence of 15-18 predorsal scales. The description of the new species increases the number of species in Xenurobrycon to six. An updated key to the species of the genus is provided.
Acesso aberto (Open Access)
Revisão taxonômica do gênero Microcharacidium Buckup, 1993 (Ostariophysi: Characiformes: Crenuchidae)
(Universidade Federal do Pará, 2019-02) VIEIRA, Lorena Sanches; FERREIRA, André Luiz Netto; http://lattes.cnpq.br/1272360228203358; https://orcid.org/0000-0002-3096-0411
Acesso aberto (Open Access)
Tometes camunani (Characiformes: Serrasalmidae), a new species of phytophagous fish from the Guiana Shield, rio Trombetas basin, Brazil
(2013-06) ANDRADE, Marcelo Costa; GIARRIZZO, Tommaso; JÉGU, Michel Louis Arthur Marie Ange François
A new species of Serrasalmidae, Tometes camunani, is described from the upper drainages of the rio Trombetas basin, Pará State, Brazil. The new species is distinguished from its congeners by having neurocranium with a slight concavity at the level of the frontal bone (vs. concavity absent, dorsal profile of neurocranium straight). It can be further distinguished from its congeners by having teeth with central cusp taller and acute (vs. central cusp shorter and with rounded edge in T. trilobatus), a terminal mouth (vs. upturned mouth in T. lebaili), and 12-26 prepelvic spines (vs. 0-9 in T. makue). The new species is strictly rheophilic like other species of Tometes, and occurs exclusively in the rapids of shield rivers, complex and fragile biotopes that are threatened by anthropogenic activities. An identification key to the species of the Myleus group is provided.
Acesso aberto (Open Access)
Variação geográfica em Schizodon dissimilis (Garman, 1890) e diversidade genética e filogeográfica do grupo Schizodon fasciatus sensu lato (Characiformes: Anostomidae)
(Universidade Federal do Pará, 2013) ABREU, João Marcelo da Silva; SCHNEIDER, Horacio; http://lattes.cnpq.br/3621033429800270