Figure 1: Distributional knowledge of agamid lizards across Africa.

In (a), 1,454 geo-referenced and quality-checked records across all 74 species of agamid lizards are shown. The records are spatially unique at 10 × 10 km resolution. In (b), examples of binary species distribution maps at 10 × 10 km resolution are illustrated as derived from occurrence records and species distribution modelling. Species with <5 records (e.g. Trapelus savignii and Agama robecchii) were not modelled. Species with sample sizes 20 > x ≥ 5 (e.g. Trapelus aspersus and Agama planiceps) were modelled with a bioclimatic envelop (surface range envelope) model. Species with ≥20 records were modelled either with a bioclimatic envelop model (e.g. Agama sankaranica), machine-learning methods such as Maxent (e.g. Agama finchi), or generalized boosting models (e.g. Agama lionotus). In cases where a shortage of locality records did not allow to accurately predict a species distributional range (e.g. Agama planiceps), model predictions were complemented with expert-based range maps (shown with green lines). In (c), agamid species richness is illustrated, derived from summing up all individual species distributions for a grid in cylindrical equal area projection with 110 × 110 km resolution (equivalent to c. 1° × 1° near the equator). Species distributions were modelled using the statistical programming language R and maps were created using ArcGIS (version 10.2, ESRI, Redlands, CA, USA).