Subspeciation befogged by the 'Seligmann effect': the case of Laudakia stellio (Reptilia : Sauria : Agamidae) in southern Sinai, Egypt

摘要

A study aimed at clarifying the taxonomic status of the variable hardun population of the south Sinai mountains, hitherto included in Laudakia stellio brachydactyla, encountered the confounding role of the "Seligmann effect" - the biometrical difference between original (whole)- tailed and regenerated (or broken)- tailed individuals. We morphologically examined museum specimens from the Negev, Israel, and Sinai, Egypt (N = 117; including 58 focal specimens used in all analyses). We used 23 conventional mensural, meristic, and qualitative characters (besides sex). Biometry was statistically analysed, separately for each sex, within and between two geographically disparate populations constituting potential subspecies, typical L. s. brachydactyla in the Negev and north Sinai, and the questioned south Sinai population. Multivariate analyses poorly separated the two geographical populations. Within each of these, the original-tailed and regenerated-tailed subsamples significantly differed in some characters ("Seligmann effect"). After excluding the regenerated-tailed specimens, principal components analysis separated the two populations at conventional subspecies level. The two significantly differ in several characters, in one without overlap. Hence the south Sinai population is described as L. s. salehi Werner n. ssp. The morphology-based key distinguishing them was tested on additional specimens and yielded geographically coherent results for all specimens. Minor directional asymmetry of the subdigitalia was left-dominant and highly significant only in the regenerated-tailed subsample (lumping sexes and regions). Associations of significant inter-character correlations differed a little between the two subspecies, indicating a possibility of functional and ecological differences.