title: B microchromosomes in the family Curimatidae (Characiformes): mitotic and meiotic behavior.
abstract: Cyphocharax voga (Hensel, 1870), Cyphocharax spilotus (Vari, 1987), Cyphocharax saladensis (Meinken, 1933), Cyphocharax modestus (Fernández-Yépez, 1948), Steindachnerina biornata (Braga & Azpelicueta, 1987) and Steindachnerina insculpta (Fernández-Yépez, 1948) collected from two hydrographic basins. All samples presented 2n=54 meta-submetacentric (m-sm) chromosomes and FN equal to 108, and 1 or 2 B microchromosomes in the mitotic and meiotic cells of the six sampled populations showing inter-and intraindividual variation. The analysis of the meiotic cells in Cyphocharax saladensis, Cyphocharax spilotus, and Cyphocharax voga showed a modal number of 54 chromosomes in the spermatogonial metaphases and 27 bivalents in the pachytene, diplotene, diakinesis and in metaphase I stages, and 27 chromosomes in metaphase II; in Cyphocharax modestus, Steindachnerina biornata, and Steindachnerina insculpta, spermatogonial metaphases with 54 chromosomes and pachytene and metaphase I with 27 bivalents were observed. The B microchromosome was observed as univalent in the spermatogonial metaphase of Cyphocharax spilotus, in the pachytene stage in the other species, with the exception of Cyphocharax saladensis, and Steindachnerina biornata in metaphase I. New occurrences of the B microchromosome in Cyphocharax voga, Cyphocharax saladensis and Steindachnerina biornata were observed, confirming that the presence of this type of chromosome is a striking characteristic of this group of fish.
authors.affiliation: Laboratório de Citogenética Animal, Centro de Ciências Biológicas, Departamento de Biologia Geral, CCB, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid, PR 445, Km 380, CEP 86051-970, P.O. Box 6001, Londrina, Paraná, Brasil.
authors.forename: Tatiane Ramos
authors.initials: TR
authors.lastname: Sampaio
authors.forename: Waleska
authors.initials: W
authors.lastname: Gravena
authors.forename: Juceli Gonzalez
authors.initials: JG
authors.lastname: Gouveia
authors.forename: Lucia
authors.initials: L
authors.lastname: Giuliano-Caetano
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: Dias
keywords: B microchromosome; curimatids; meiosis