CHARACTERIZATION OF MITOTIC CHROMOSOMES OF 4 SPECIES OF THE GENUS DIPLODUS - KARYOTYPES AND CHROMOSOMAL NUCLEOLAR ORGANIZER REGION PHENOTYPES

Karyotypes have been described in four Mediterranean species of the ge nus Diplodus (Teleostei, Sparidae), D. vulgaris, D. puntazzo, D. sargu s and D. annularis. Chromosomes were mainly acrocentric in all but D. vulgaris, where certain chromosome pairs were subtelocentric. A remark able intraspecific heteromorphism in the number of NOR-bearing chromos omes along with a substantial interspecific variability in position of chromosomal ACO signals have been encountered. The presumed origin of multiple NOR-bearing chromosomes in Diplodus species and variation of the NOR location is discussed. (C) 1996 The Fisheries Society of the British Isles