Sky Islands of Mozambique harbour cryptic species of chameleons: Description of four new species of sylvan chameleons (Squamata: Chamaeleonidae: Nadzikambia Tilbury, Tolley & Branch, 2006)

Abstract Several populations of forest-living chameleons in the genus Nadzikambia have been recorded from the montane sky island forests in northern Mozambique. These populations have not been evaluated for their species status, despite the potential for these allopatric populations having diverged at the species level due to vicariance of forest since the mid-Miocene. With only two described species of Nadzikambia, we hypothesised that candidate (new) species occur on each of four additional montane sky islands surveyed. We applied an integrative taxonomic approach to evaluate this, using morphological and genetic data collected from each population. Their distributions were mapped, the morphological dataset was quantitatively analysed using a multivariate analysis, and one nuclear and three mitochondrial genes were sequenced to generate a phylogeny and allele networks. Independent species delimitation analyses were applied to the genetic dataset (mPTP, SpeciesIdentifier, p distances) as supporting evidence for candidate species. By applying integrative taxonomy under the General Lineage Species Concept, we find support for four new species of Nadzikambia. The montane forests where they occur have declined in extent due to slash and burn agriculture and these forest endemics are presumed to be in a proportional decline as their habitat contracts. By examining historical and present-day satellite imagery, we show that all Nadzikambia species have lost significant proportions of their range. Given they do not occur outside these forests, these species are in imminent danger of extinction.