Levels of island endemism of the herpetofauna in the Sporades, expressed as the number of endemic taxa relative to the total number of species on an island (endemic is defined here as any island lineage described as discrete in the taxonomic literature at either the species or the subspecies level, e.g., P. gaigeae, P. erhardii ruthveni, M. kotschyi fuchsi). Older and more isolated islands (on the eastern end of the Sporades chain) have a stronger endemic element. Smaller islands also have high endemism scores, likely because relatively hostile conditions allow only for the persistence of old, locally-evolved taxa.