Morphometric and karyological differentiation among populations of Discoglossus pictus (Discoglossidae: Anura) in Eastern North Africa

To assess karyological and morphometric diversity within Discoglossus pictus Otth 1837, morphometric and cytogenetic analyses were carried out on five populations from the northern Tunisia and Algeria. A total of eight morphometric adult traits were evaluated, tadpole oral disc structure was described and chromosome patterns were assessed by means of conventional staining and banding methods (C-, Ag-NOR and CMA₃ banding). Karyological data indicated the same chromosome and chromatin characters among the five populations. We observed also the same oral disk structure (LTRF: ⅔) in all studied Discoglossus tadpoles. However, we found significant differences in morphometric parameters of the specimens from these localities. Discriminant Function Analysis (DFA) of morphometric variables correctly classified 88% of individuals to their original localities. The pattern of morphometric variation does not match the genetic observation, which suggests that body shape differences result from the phenotypic plasticity correlated with local climatic factors.