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| Nakayama,Celeste Mutuko; Feldberg,Eliana; Bertollo,Luiz Antonio Carlos. |
| Six species of Serrasalmidae from the central Amazon, representatives of the genera Serrasalmus (S. elongatus, S. maculatus, S. cf. rhombeus, and S. rhombeus), Pygocentrus (P. nattereri), and Colossoma (C. macropomum), were analyzed regarding the distribution of the Ag-NORs, C-positive heterochromatin and 18S and 5S rRNA genes on the chromosomes. All specimens had 2n = 60 chromosomes, except S. cf. rhombeus, with 2n = 58, and C. macropomum with 2n = 54 chromosomes. The Ag-NORs were multiple and located on the short arms of subtelo-acrocentric chromosomes in all Serrasalmus species and in P. nattereri, but were found on metacentric chromosomes in C. macropomum. The 18S rDNA sites were usually coincident with Ag-NORs, although some species had a higher... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosomal evolution; Fish; Heterochromatin; Piranhas; Ribosomal genes. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252012000100005 |
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| Ortí,Guillermo; Sivasundar,Arjun; Dietz,Kelly; Jégu,Michel. |
| Previous studies based on DNA sequences of mitochondrial (mt) rRNA genes showed three main groups within the subfamily Serrasalminae: (1) a "pacu" clade of herbivores (Colossoma, Mylossoma, Piaractus); (2) the "Myleus" clade (Myleus, Mylesinus, Tometes, Ossubtus); and (3) the "piranha" clade (Serrasalmus, Pygocentrus, Pygopristis, Pristobrycon, Catoprion, Metynnis). The genus Acnodon was placed as the sister taxon of clade (2+3). However, poor resolution within each clade was obtained due to low levels of variation among rRNA gene sequences. Complete sequences of the hypervariable mtDNA control region for a total of 45 taxa, and additional sequences of 12S and 16S rRNA from a total of 74 taxa representing all genera in the family are now presented to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Piranhas; Pacus; D-loop; Phylogeny; Bayesian inference. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200030 |
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| ROSSIN,MARÍA A.; FRANCESCO,PABLO N. DE; IRIGOITIA,MANUEL M.; SCARABOTTI,PABLO A.; TAGLIORETTI,VERÓNICA; TIMI,JUAN T.. |
| Abstract Abstract: Three piranha species, Serrasalmus maculatus, S. marginatus and Pygocentrus nattereri, living sympatrically in the lower Paraná River (Argentina) were examined searching for nasal monogeneans to know its diversity and distribution. Four species of monogeneans belonging to Rhinoxenus were found parasitizing the nasal cavities. Two new species are described, and new morphological data of 2 previously described species is provided. Rhinoxenus argentinensis n. sp. is characterized by having the male copulatory organ (MCO) as a coiled tube with a reel shaped-base; an elongated accessory piece articulated to base of MCO; a sinistral vagina with a sclerotized vestibule, and a sclerotized cap of the ventral anchor laterally modified forming a... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Piranhas; Nasal parasites; Rhinoxenus spp; South American rivers.. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000700621 |
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