Cytogenetic analyses in three species of Moenkhausia Eigenmann, 1903 (Characiformes, Characidae) from Upper Paraná River (Misiones, Argentina)


  • Kevin I. Sánchez Instituto Patagónico para el Estudio de los Ecosistemas Continentales (IPEEC-CONICET), U9120-ACD Puerto Madryn, Chubut
  • Fabio H. Takagui Laboratório de Citogenética Animal, Departamento de Biologia Geral, CCB, Universidade Estadual de Londrina, Londrina, Paraná
  • Alberto S. Fenocchio Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Instituto de Biología Subtropical (UNaM-CONICET), Posadas, Misiones



neotropical fishes, Moenkhausia, supernumerary chromosomes, heterochromatin, Ag-NORs


Moenkhausia Eigenmann, 1903 is one of the most diverse genera within Characidae, being an important component of the Neotropical fish fauna. Three members of this genus were cytogenetically analyzed: M. dichroura Kner, 1858, M. intermedia Eigenmann, 1908 and M. sanctaefilomenae Steindachner, 1907. The three species showed 2n = 50 bi-armed chromosomes (NF = 100) and different karyotype formulas: 22m + 22sm + 6st in M. dichroura, 16m + 28sm + 6st in M. intermedia, and 12m + 32sm + 6st in M. sanctaefilomenae. In addition, supernumerary chromosomes (or B-chromosomes) were detected in M. intermedia and M. sanctaefilomenae. C-positive bands were restricted to pericentromeric regions, secondary constrictions and supernumerary chromosomes. Active nucleolus organizer regions (Ag-NORs) and positive CMA3 bands were observed in a single pair of sm chromosomes. Pericentromeric DAPI positive signals were evidenced on chromosomes of M. sanctaefilomenae only. Overall, the three species showed a conservative karyotype macrostructure (diploid number, number of chromosome arms) and variations in microstructure (karyotype formulas, presence/absence of supernumerary chromosomes). We discuss how the observed differences could have been shaped.


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How to Cite

Sánchez, K. I., Takagui, F. H., & Fenocchio, A. S. (2022). Cytogenetic analyses in three species of Moenkhausia Eigenmann, 1903 (Characiformes, Characidae) from Upper Paraná River (Misiones, Argentina). Caryologia, 74(4), 3-10.