Comparative cytogenetics of Serrasalmidae (Teleostei: Characiformes): The relationship between chromosomal evolution and molecular phylogenies

Abstract

Serrasalmidae has high morphological and chromosomal diversity. Based on molecular hypotheses, the family is currently divided into two subfamilies, Colossomatinae and Serrasalminae, with Serrasalminae composed of two tribes: Myleini (comprising most of pacus species) and Serrasalmini (represented by Metynnis, Catoprion, and remaining piranha’s genera). This study aimed to analyze species of the tribes Myleini (Myloplus asterias, M. lobatus, M. rubripinnis, M. schomburgki, and Tometes camunani) and Serrasalmini (Metynnis cuiaba, M. hypsauchen, and M. longipinnis) using classical and molecular cytogenetic techniques in order to understand the chromosomal evolution of the family. The four species of the genus Myloplus and T. camunani presented 2n = 58 chromosomes, while the species of Metynnis presented 2n = 62 chromosomes. The distribution of heterochromatin occurred predominantly in pericentromeric regions in all species. Tometes camunani and Myloplus spp. presented only one site with 5S rDNA. Multiple markers of 18S rDNA were observed in T. camunani, M. asterias, M. lobatus, M. rubripinnis, and M. schomburgkii. For Metynnis, however, synteny of the 18S and 5S rDNA was observed in the three species, in addition to an additional 5S marker in M. longipinnis. These data, when superimposed on the phylogeny of the family, suggest a tendency to increase the diploid chromosome number from 54 to 62 chromosomes, which occurred in a nonlinear manner and is the result of several chromosomal rearrangements. In addition, the different karyotype formulas and locations of ribosomal sequences can be used as cytotaxonomic markers and assist in the identification of species.

Macroevolutionary consequences of karyotypic changes in the neotropical Serrasalmidae fishes (Ostariophysi, Characiformes) diversification

“…However, in recent years, studies of diets in these species have reinforced that they are considerably more diverse than previously predicted (Kolmann et al 2021). (Favarato et al 2021). The cytogenetic data, when superimposed on the phylogeny of the family, revealed a tendency to increase the diploid chromosome numbers from 54 to 62 chromosomes, which occurred in a nonlinear manner and is the result of several chromosomal rearrangements (Favarato et al 2021).…”

“…(Favarato et al 2021). The cytogenetic data, when superimposed on the phylogeny of the family, revealed a tendency to increase the diploid chromosome numbers from 54 to 62 chromosomes, which occurred in a nonlinear manner and is the result of several chromosomal rearrangements (Favarato et al 2021). However, little is discussed about whether the chromosomal changes detected are associated with the cladogenetic diversi cation of this family, especially considering their phylogenetic and biogeographic context.…”

“…This group, which includes about 101 valid species and 16 genera, has a high morphological diversity, with elevated bodies, laterally compressed, with abdominal spines and long dorsal ns (Kolmann, et al 2021). Based on molecular hypotheses, the family is currently divided into two subfamilies, Colossomatinae and Serrasalminae, with Serrasalminae composed of two tribes: Myleini (comprising most of pacus species) and Serrasalmini (represented by Metynnis, Catoprion, and remaining piranha's genera) (Favarato et al 2021). They inhabit almost all the continental basins of South America (Jégu, 2003;Fricke et al 2022) and a variety of lotic and lentic environments (Goulding, 1980), where they perform ecological functions, and support important continental sheries (Araujo-Lima and Goulding, 1997).…”

Karyotype Evolution of Talking Thorny Catfishes Anadoras (Doradidae, Astrodoradinae): A Process Mediated by Structural Rearrangements and Intense Reorganization of Repetitive DNAs

“…Neotropical freshwater fishes represent one of the most diversified animal groups on earth due to their remarkable morphological and chromosomal diversity, and they are considered an excellent model for evolutionary studies [Machado et al, 2018;de Moraes et al, 2021;Favarato et al, 2021;Sassi et al, 2021;Takagui et al, 2021]. Over the past years, comparative cytogenetic studies have generated relevant information that contributes to the understanding of phylogenetic relationships, taxonomy, and diversification of some Brazilian freshwater fish lineages [Ferreira et al, 2017[Ferreira et al, , 2020Prizon et al, 2017;Usso et al, 2018].…”