The Chromosomes of Laticauda and a Review of Karyotypic Evolution in the Elapidae

Abstract

Kayrotypic data are presented for three species of sea kraits, Laticauda. The diploid number of L. semifasciata is 38. There is obvious female heterogamety. The diploid number of L. colubrina is 34, and female heterogamety is not obvious. Haploid counts of male L. laticaudata indicate n = 20. Karyotypic data of all sea snakes and all terrestrial elapids are reviewed. The hydrophiines are conservative in number of autosomal macrochromosomal arms and relative arm lengths. Karyotypic evolution primarily involves centric fissions and rearrangement of sex chromosomes. The genus Microcephalophis should be synonomized with Hydrophis. The Australian elapid Notechis has a karyotype that is very similar to Laticauda colubrina. This is perhaps the primitive karyotype of the elapid radiation.