PLOIDY DIVERSITY AND THE PRODUCTION OF BALANCED GAMETES IN MALE TWIST-NECKED TURTLES (PLATEMYS-PLATYCEPHALA)

The twist-necked turtle Platemys platycephala (Pleurodira) is remarkab le for its diversity of ploidy levels. Viable diploids, triploids, dip loid-triploid mosaics, and triploid-tetraploid mosaics are found in na tural populations. In contrast with other species of polyploid reptile s, which are all female and parthenogenetic, both male and female poly ploids are found in the twist-necked turtle, and reproduction occurs o stensibly by a sexual mode. In this study, flow cytometric and cytolog ical analyses demonstrate that, regardless of somatic ploidy constitut ion, males have diploid testicular cell populations and produce balanc ed gametes. Normal fertility is inferred for polyploid males of this s pecies.