Paradoxical reproduction and body size in the rock lizard, Agama atra atra, in Namaqualand, South Africa

Abstract

The rock lizard Agama atra atra from Namaqualand differs in both body size and reproduction from other populations of this species occurring elsewhere in southern Africa. Both sexes from Namaqualand are significantly larger than their counterparts in the south-western Cape. While reproduction in this species is strongly seasonal elsewhere, it is apparently continuous in Namaqualand. Females with vitellogenic ovarian follicles and/or oviducal eggs were collected during the winter months, a time when females are typically re productively quiescent in other populations. Aseasonal reproduction and large body size of this species in Namaqualand do not correlate with prevailing environmental conditions in the area. The presence of al least one other species with continuous reproduction and two others with tropical affinities in the same general area, suggests that the Namaqualand population of A. a. atra may be a tropical relict.