Resumen

COWPER COLES, F; SANCHEZ, S  y  JORGE, L.C. Estructura cariotípica de dos poblaciones de Rhamdia quelen (Pisces, Siluriformes) de los ríos Paraná y Paraguay (Argentina). Rev. vet. [online]. 2013, vol.24, n.2, pp.144-147. ISSN 1669-6840.

Thirteen specimens of Rhamdia quelen captured in the Paraná river (4 females and 9 males) and 7 specimens from the Paraguay river (3 females and 4 males), were studied. In total, 244 metaphases were registered. R. quelen showed a diploid number of 58 chromosomes. With a karyotype formula of 46M/SM + 12ST, the fundamental number (FN) was 116; there were no differences between the two populations. There was no evidence of occurrence of chromosomal heteromorphism related to sex. The nucleolus organizer regions (NOR) in the two populations were located in the terminal region of the short arm of a subtelocentric pair (pair 27). The A complement chromosomes showed bands C+ distributed mainly above the NOR on pericentromeric and terminal regions in a few chromosomes. It is concluded that for the analyzed populations of R. quelen, the karyotypic features are conserved regarding the diploid number of 58, with two-arms chromosomes, single nucleolar organizer region, and poor C banding pattern.

Palabras clave : Rhamdia quelen; Caryotype; C-banding; NOR; Paraná and Paraguay rivers.

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