THE KARYOTYPE OF SCORPAENA BRASILIENSIS AND S. ISTHMENSIS (SCORPAENIFORMES: SCORPAENIDAE: SCORPAENINAE) FROM MARGARITA ISLAND, VENEZUELA

Resumen

Abstract: We report on the results of the cytogenetic study of Scorpaena brasiliensis and S. isthmensis from Venezuela by conventional Giemsa staining and silver staining. S. brasiliensis has a complement 2n= 46 composed of two metacentric (M), 8 submetacentric (SM) and 36 subtelo/acrocentric (ST/A), NF= 56 with NORs located in the terminal position of the short arms of the pair number 7, whereas S. ithsmensis showed a diploid number 2n= 38, composed of 8 M, 8 SM y 22 A, NF= 54 with NORs located in terminal position in the long arm of the pair number 9. The comparison of these results with those of a previous report from Brazil reflects a clear differentiation at chromosomal level between the populations from the Caribbean and those from Brazil, which is, explained as the result of gross chromosome reorganization involving fusion, pericentric inversion and translocation processes. Since the Caribbean and Brazilian populations of these species are separated by the massive discharge of fresh water from the Amazonas and the Orinoco rivers, we suggest that further studies will be necessary to determine the status of these two groups either as distinct populations or as separate species.

Keywords: Karyotype, NORs, populations, Scorpaenidae, Scorpaena brasiliensis, S. isthmensis.