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

ENGLISH 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 stongly 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 reproductively quiescent in other populations. A seasonal reproduction and large body size of this species in Nimaqualand do not correlate with prevailing environmental conditions in the area. The presence of at 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 maybe a tropical relict. ************ AFRIKAANSE OPSOMMING: Die bloukopkoggelmander, Agama atrar atra, wat in Namakwaland voorkom, verskil in beide liggaamsgrootte en voortplanting van ander populasies van hierdie spesie wat elders in suidelike Afrika aangetref word. Beide geslagte van die Namakwalandse vorm is aansienlik groter as hul eweknie elders. Voortplanting by hierdie spesie is elders uitgesproke seisoenaal, maar in Namakwaland is dit o nskynlik aaneenlopend. Wyfies met vitellogenetiese folikels en/of eiers in die ovidukte, is gedurende die wintermaande hier versamel , 'n tyd van die jaar wanneer wyfies tipies in 'n reproduktiewe rusfase verkeer in ander populasies. Aaneenlopende voortplanting en groot liggaamsgrootte van hierdie spesie in Namakwaland korreleer nie met heersende omgewingstoestande in die gebied nie. Die teenwoordigheid van ten minste een ander spesie met aaneenlopende voortplanting en twee ander met tropiese verwantskappe in dieselfde algemene gebied, dui daarop dat die Namakwaland populasie van A . a. atra moontlik 'n tropiese oorblyfsel mag wees.