Phenetic analysis of populations of Porcellionides pruinosus (Brandt, 1833) (Crustacea, Isopoda, Oniscidea)

The cosmopolitan species, Porcellionides pruinosus (Brandt, 1833), exhibited a geographical variation of its morphological features and its reproduction pattern. In fact, some Tunisian populations had a seasonal reproductive period and other ones showed a reproductive activity. A phenetic analysis has been performed to compare populations belonging to P. pruinosus from different geographical localities. For this, nineteen quantitative characters in 800 specimens of P. pruinosus issued from nine populations located in the North, the Centre, and the South of Tunisia, and one population from Athens (Greece) were studied. These populations were characterized by different reproductive behaviours. The populations of Tabarka, Korba, and Tamerza showed reproductive activity, whereas those of Garat Nâam, Raccada, Sahline, Gafsa, Rdayef, Gabès, and Athens exhibited a seasonal reproductive period. The variability of the first three axes of the principal components analysis (PCA) and their significance showed an intraspecific variability structure. The graphical representation of the population's dispersion generated by the two first axes (63.55% of the total variability) revealed a great heterogeneity among females of the different populations of P. pruinosus. The Garat Nâam population was set apart from the other ones by its cephalic width and length and also by its apophysis length. Furthermore, cephalic and uropod length separated the Garat Nâam and Tabarka populations. The dendrogram, based on Euclidean coordinates, confirms an isolation of the populations of Tabarka and Garat Nâam, exhibiting respectively reproductive activity and seasonal reproduction. However, the other populations do not show any relationship with the reproduction behaviour. They were clustered in two groups. The first one is represented by the populations of the Southeast and the West of Tunisia. The second pooled the populations of the Northeast and the Centre of Tunisia with the population of Athens (Greece). Phenetic analysis of Tunisian populations exhibits an important heterogeneity, which is worth noting. Thus, we need to complete and deepen this study by genetic analysis and crossbreeding tests in order to define the taxonomic status of these populations. To cite this article: M.S. Achouri, F. Charfi-Cheikhrouha, C. R. Biologies 331 (2008).