Morphological variability in and distributional data on Phaleria bimaculata populations from islands of the Central Mediterranean area

Abstract

This study aimed to collect new taxonomic and distribution data on Phaleria bimaculata (L.) (Coleoptera Tenebrionidae) from Sicily (southern Italy), the circum-Sicilian islands and the Maltese archipelago. Particular attention was paid to the diagnostic morphological features observed in the populations sampled, focusing on the subspecies Phaleria bimaculata marcuzzii Aliquò. P. bimaculata individuals were collected from 20 different locations, of which 2 were located in the Sicilian mainland, 9 in circum-Sicilian islands and 9 in the Maltese Islands. In addition, four Phaleria acuminata Kuster populations were also recorded along southern Sicilian shores. The two Phaleria species were never recorded in sympatry within the current study. Geometric morphometrics were deployed to quantify and analyze the intra-specific differentiation in the shape of two external anatomical structures, i.e. the pronotum and the elytra. The elytra of the individuals from the Aeolian island of Vulcano, locus typicus of the ssp. marcuzzii, were more elongated and elliptical in comparison to the Maltese and the Sicilian individuals, underscoring the degree of genetic differentiation within different populations of the species.