Navegando por Autor "WOSIACKI, Wolmar Benjamin"

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Acesso aberto (Open Access)
Description of a new species of Ituglanis (Siluriformes: Trichomycteridae) from Serra dos Carajás, rio Tocantins basin
(2012-09) WOSIACKI, Wolmar Benjamin; DUTRA, Guilherme Moreira; MENDONÇA, Marina Barreira
A new species of Ituglanis is described from the rio Tocantins basin, State of Pará, Brazil. Ituglanis ina, new species, is distinguished from its congeners by the presence of a dark vertical bar over the base of the caudal-fin rays (vs. no bars over caudal-fin base); and by the presence of a middle trunk line of tiny neuromasts extending along the flank until the vertical through the dorsal fin, or near the caudal-fin base (vs. no middle trunk line of tiny neuromasts). Ituglanis ina can be further distinguished by a combination of characters related to color pattern and morphology. Comments on the relationship between Ituglanis species are presented.
Acesso aberto (Open Access)
Karyotypic and morphological divergence between two cryptic species of Eigenmannia in the Amazon basin with a new occurrence of XX/XY sex chromosomes (Gymnotiformes: Sternopygidae)
(2015-06) SILVA, Danillo dos Santos; PEIXOTO, Luiz Antônio Wanderley; PIECZARKA, Julio Cesar; WOSIACKI, Wolmar Benjamin; READY, Jonathan Stuart; NAGAMACHI, Cleusa Yoshiko
Eigenmannia species are widely distributed in the Neotropics, with eight valid species currently recognized. Populations of Eigenmannia from three locations in the eastern Amazon were investigated using cytogenetic and morphological techniques, revealing two taxa designated here as Eigenmannia sp. "A" and Eigenmannia sp. "B". The species differ in three morphometric characters, two meristic characters, and one osteological character. Eigenmannia sp. "A" presents 2n = 34 (22 m/sm+12 st/a) and Eigenmannia sp. "B" presents 2n = 38 (14 m/sm+24st/a) and simple differentiated sex chromosomes of the type XX/XY. In both species the Constitutive Heterochromatin (CH) rich in A-T bases is distributed in the centromeric region of all chromosomes. Eigenmannia sp. "B" also presents CH blocks in the interstitial region of chromosome pairs 8, 9 and X which are positively stained with CMA3, indicating G-C rich regions. The NOR is located on the short arm of chromosome pair 17 of Eigenmannia sp. "A" and on the short arm of pair 14 of Eigenmannia sp. "B". FISH with rDNA probes hybridized to different-sized regions between homologs, suggesting heteromorphism. The differentiation of the X chromosome in Eigenmannia sp. "B" could be the result of amplification of repetitive DNA sequences.
Acesso aberto (Open Access)
Rapid assessment of the ichthyofauna of the southern Guiana Shield tributaries of the Amazonas River in Pará, Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2020-03) DUTRA, Guilherme Moreira; FREITAS, Tiago Magalhães da Silva; PRUDENTE, Bruno da Silveira; SALVADOR, Gilberto Nepomuceno; LEÃO, Manuela Dopazo de Vasconcellos; PEIXOTO, Luiz Antônio Wanderley; MENDONÇA, Marina Barreira; NETTO-FERREIRA, André Luiz; SILVA, Fabio Roberto Ribeiro da; MONTAG, Luciano Fogaça de Assis; WOSIACKI, Wolmar Benjamin
The Northern Pará Drainage System encompasses the left-bank tributaries of the Amazonas River in the southern Guiana Shield region of Pará state, Brazil. Five of the region’s state protected areas are considered strategic for the conservation of its biodiversity. In the present study, we assessed the ichthyofauna of the five state protected areas of the Northern Pará Drainage System. Seven expeditions were conducted between January 2008 and January 2009, which surveyed stretches of the Cuminá, Cuminapanema, Curuá, Jari, Mapuera, Nhamundá, and Paru rivers. These surveys yielded 286 species belonging to 38 families and eight orders, including seven new records of fish species for Brazil, six of which are also new records for the Amazon basin. Our results provide a valuable database for future research and conservation programs in the protected areas of the region.