title: Cytogenetic data onAncistrussp. (Siluriformes, Loricariidae) of the Paraguay River basin (MS) sheds light on intrageneric karyotype diversification.
abstract: AncistrusKner, 1854 is a diverse catfish genus, currently comprising 66 valid species, but karyotype data were recorded for 33 species, although only ten have their taxonomic status defined. Considerable karyotype diversity has been found within this genus, with 2n varying from 34 to 54 and structural variability including heteromorphic sex chromosomes. In many cases, uncertainty on the taxonomic status of the study populations hampers reliable interpretation of the complex chromosomal evolutionary history of the group. This study aims to present the first karyotype data for a population of theAncistrussp. collected in Criminoso stream (tributary of the Paraguay River Basin, Mato Grosso do Sul, Brazil) in which a combination of different chromosomal markers was used and results integrated in broad discussion on karyotype evolution in the genus. The specimens presented 2n=42 with 18m+16sm+8st and a single NOR revealed by silver nitrate and fluorescencein situhybridization (FISH) with 18S rDNA probe, located in pair No. 10. Clusters of 5S rDNA were located in the pericentromeric region of three chromosomes: pair No. 1 (metacentric) and one of the homologues of the nucleolar pair No. 10. Heterogeneity in the molecular composition of the heterochromatin was confirmed by the association of C-banding and fluorochrome CMA3/DAPI-staining. Exploring the differential composition of constitutive heterochromatin inAncistrusmay provide an important perspective to understand genome organization and evolution within this group. Our data reinforce the chromosomal diversity present inAncistrusgenus and we discuss the potential sources these variation. The karyotype structure ofAncistrussp. "Criminoso stream" appears to be consistent with the existence of a new candidate species.
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Ana Camila
authors.initials: AC
authors.lastname: Prizon
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Luciana Andreia
authors.initials: LA
authors.lastname: Borin-Carvalho
authors.affiliation: Departamento de Genética, Universidade Federal do Paraná, UFPR, Centro Politécnico, Jardim Botânico, 81531-980, Curitiba, Paraná, Brazil.
authors.forename: Daniel Pacheco
authors.initials: DP
authors.lastname: Bruschi
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Marcos Otávio
authors.initials: MO
authors.lastname: Ribeiro
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Ligia Magrinelli
authors.initials: LM
authors.lastname: Barbosa
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Greicy Ellen de Brito
authors.initials: GE
authors.lastname: Ferreira
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Andréa
authors.initials: A
authors.lastname: Cius
authors.affiliation: Departamento de Biologia/ Nupélia, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Claudio Henrique
authors.initials: CH
authors.lastname: Zawadzki
authors.affiliation: Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, UEM, Avenida Colombo, 5790, 87020-900, Maringá, Paraná, Brazil.
authors.forename: Ana Luiza de Brito
authors.initials: AL
authors.lastname: Portela-Castro
keywords: Ancistrini; CMA3/DAPI; cytotaxonomy; heterochromatin; rDNA