Distribution of Bradypodion taeniabronchum (Smith 1831) and other dwarf chameleons in the eastern Cape Floristic Region of South Africa

Abstract

The evolutionary relationships and taxonomic status of dwarf chameleons in the eastern Cape Floristic Region is not well understood. Through a combination of field observations and mito‐chondrial DNA sequencing (ND2 and 16S), it has become apparent that morphological and genetic evidence are often in conflict. In some instances, species that are morphologically quite different, show close genetic relationships, eg., Bradypodion taeniabronchum and B. ventrale. In other cases there are substantial genetic differences between lineages, with little morphological differentiation. For example, dwarf chameleons from the Kouga and the Baviaanskloof mountains were thought to represent a single undescribed species. However, chameleons from these two mountain ranges show large sequence divergence (6.8% for ND2) that is more than twice the value between B. taeniabronchum and B. ventrale. The evolutionary relationships within this group are reticulate in nature, making taxonomy difficult to resolve. Application of only mitochondrial data to resolve the taxonomy of this group is therefore insufficient, because mitochondrial DNA may only indicate historical isolation of lineages, and if used independently, may not be a good indicator of species definitions. Therefore our next step toward resolving the taxonomy of this group is the inclusion of nuclear DNA markers, in conjunction with a full morphological analysis.