EXCLUSIVE CYTOTYPE IN Parauchenipterus galeatus (SILURIFORMES, AUCHENIPTERIDAE) IN THE EASTERN NORTH-EAST ATLANTIC BASIN OF BRAZIL: INDICATION OF A SPECIES COMPLEX

• Published in: Biota Amazônia
• Main Authors: Araújo, Washington Candeia, Molina, Wagner Franco
• Other Authors: CNPq, CAPES, FINEP
• Format: Article in Journal/Newspaper
• Language: Portuguese
• Published: Universidade Federal do Amapá 2013
• Subjects: North East Atlantic
• Online Access: http://periodicos.unifap.br/index.php/biota/article/view/643; https://doi.org/10.18561/2179-5746/biotaamazonia.v3n2p33-39

Endemisms among the ichthyofauna of the hydrographic Brazilian basins has been showed frequent, mainly due to vicariance or dispersal processes. Several species constitute genuinely complexes of cryptic species, in clear process of differentiation. Cytogenetic analysis performed in the catfish, Parauchenipterus galeatus, in the basin of the Eastern North-east Atlantic basin of Brazil revealed a karyotype with 2n = 58 (24m+16sm+10st+8a; NF=108), with unique NORs sites located in the distal region of a submetacentric chromosome pair and with reduced heterochromatic regions. This standard karyotype shown differentiated from other already described for species of others basins. The distribution of heterochromatin associated with structural variations of karyotype represent important evidences of cytogenetic differentiation of P. galeatus among the different Brazilian basins. Considering the time of divergence between large basins, it is possible that the cytogenetic differences found may represent in some cases effective post-zygotic reproductive barriers. The diversity of the species karyotype supports the existence of a species complex.Keywords: Cangati; cryptic species; fish cytogenetics; allopatric speciation. Endemismos entre as ictiofaunas das bacias hidrográficas brasileiras vêm se mostrando frequentes, principalmente decorrentes de vicariância ou dispersão. Diversas espécies constituem verdadeiramente complexos de espécies crípticas, em franco processo de diferenciação. Análises citogenéticas realizadas no bagre, Parauchenipterus galeatus, da bacia hidrográfica do NE Oriental do Brasil revelaram um cariótipo com 2n=58 (24m+16sm+10st+8a; NF=108), com RONs simples localizadas em região distal de um par cromossômico submetacêntrico, com regiões heterocromáticas reduzidas. Este padrão cariotípico se mostra diferenciado de outros já descritos para a espécie de outras bacias hidrográficas. A distribuição da heterocromatina, associada às variações estruturais do cariótipo ...