Comparative cytogenetics of Loricariidae (Actinopterygii: Siluriformes): Emphasis in Neoplecostominae and Hypoptopomatinae

• Published in: European zoological journal 2012-12, Vol.79 (4), p.492-501
• Main Authors: Ziemniczak, K., Barros, A. V., Rosa, K. O., Nogaroto, V., Almeida, M. C., Cestari, M. M., Moreira-Filho, O., Artoni, R. F., Vicari, M. R.
• Format: Article
• Language: English
• Subjects: Chromosomal evolution; Chromosomes; Cytogenetics; cytotaxonomic; phylogenetic relationships; Phylogenetics
• ISSN: 1125-0003; 2475-0255; 1748-5851; 2475-0263
• DOI: 10.1080/11250003.2012.676677

Over the last two decades, several classification changes were proposed for the family Loricariidae and their phylogenetic relationships could be only partly resolved so far. Two major problematic groups are the subfamilies Hypoptopomatinae and Neoplecostominae. Therefore, we analysed four species of this family, being three Neoplecostominae (Neoplecostomus yapo, Kronichthys lacerta and Isbrueckerichthys duseni), and one Hypoptopomatinae representative (Parotocinclus maculicauda), in order to compare the chromosomal data to other Loricariidae subfamilies and to the outgroup Trichomycterus sp. To accomplish that, conventional (diploid numbers, karyotype formulae, fundamental number and Ag-NORs - nucleolar organizer regions) and molecular chromosomal markers (dual color FISH - fluorescence in situ hybridization - with 18S and 5S rDNA probes) were used. A similar karyotype structure was reported amongst the studied species. Inferences about putative plesiomorphic chromosomal markers were established and/or corroborated in Loricariidae, such as: 2n = 54 chromosomes, small amounts of heterochromatin, a single NOR-bearing pair and synteny 18S and 5S rDNA at interstitial region. Thus, the present chromosomal analysis hypothesizes primitive chromosomal characters and contributes to a better understanding of chromosomal evolutionary processes among loricariids.