Karyotypic Evolution in Gehyra (Gekkonidae: Reptilia) I. The Gehyra Variegata-Punctata Complex.

Abstract

A karyotypic analysis of populations of the gekkos Gehyra variegata and G. punctata reveals three chromosome races in G. variegata (2n = 44; 2n = 40a; 2n = 40b), and three in G. punctata (2n = 44; 2n = 42; 2n = 38). The chromosome races have differentiated by a series of chromosome fusions. The ordered nature of these changes suggests that the phylogenetic relationships of the races cut across the current taxonomy, and it is argued that there is but one 2n = 44 race, occurring as a number of morphologically distinct populations, two of which were erroneously described as the separate Gehyra species. Isolated populations within a number of the chromosome races show pronounced morphological differences. It is believed that these gekkos are an ancient Australian group which differentiated chromosomally during a number of colonizing radiations. Since then, populations within each race have been isolated by geographic barriers and have speciated allopatrically. This suggests that the chromosome races are at least good species and may be of a higher taxon.