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Dominating global arid environments, from desert to coastal dunes, most Tenebrionidae are highly specific in their habitat preferences and display limited dispersal potential, thus exhibiting a remarkable degree of regional genetic and morphological differentiation. The tenebrionid genus Phaleria is speciose and widely distributed, with P. acuminata and P. bimaculata having a wide Mediterranean distribution, with numerous morphological differentiations at population level, often described as different taxa of doubtful taxonomical significance. In order to investigate the variability of the central Mediterranean populations of P. bimaculata and P. acuminata and to compare the results obtained with different identification techniques, these species were sampled on sandy beaches in Sicily (southern Italy) and on circum-Sicilian and Maltese islands. Collected samples were studied through the application of geometric morphometrics and the sequencing of a fragment of the mitochondrial COII gene. Geometric morphometrics and molecular analyses gave congruent results, allowing a sound separation of the two species. At the population level, the two species showed different patterns. P. acuminata showed a remarkable morphological and molecular homogeneity throughout the sampled area. Conversely, two well-characterized subclades were detected within P. bimaculata, and within the two lineages, a low-to-absent inter-populations differentiation was observed, in spite of the physical isolation of the sampled sandy beaches and of their geographical distance. These two P. bimaculata lineages, hereby named ‘‘Tyrrhenian sub-clade’’ and ‘‘Southern sub-clade,’’ might be compatible with the hypothesis of subspecific status already proposed for the populations from the Aeolian archipelago (as P. bimaculata marcuzzii Aliquo`).

Bathyporeia guilliamsoniana (Spence Bate, 1857) specimens collected in the Levantine Basin of the Mediterranean Sea displayed polymorphism in some characters. More than 100 specimens were examined and their intra-specific variation in the shape of the third epimeral plate analysed and quantified. The morphometric geometry methodology is used to assess the ‘cryptic’ variation in shape which may obscure identification. The results support the assignment of sunnivae and megalops to morphotypes of B. guilliamsoniana sensu d’Udekem d’Acoz & Vader (2005).

In the debate on how and why biodiversity evolves spatially and temporally and in an attempt to assess the further effects of anthropogenic activities, the ability of marine invertebrate to express a large spectrum of phenotypical plasticity can have a central role. The ability of a single genotype to produce more than one alternative form of morphology and/or physiological state should be larger in species living in highly changing waters like shallow habitats. Invertebrates, there, usually experience ample changes of temperature and food availability on annual, seasonal, diurnal and hourly bases which are the two main drivers leading the life histories of these organisms. In such circumstances they are expected to have a larger ability to express plastic phenotypic traits respect to species living under more stable conditions. Hence, the geometric morphometry is informative in understanding if morphology of sessile bivalves significantly changes as a function of different conditions of environmental variability. Here we focus on Brachidontes pharaonis as a model of our morphometric study as it spans intertidal, subtidal and shallow Mediterranean habitats with a range of physical and biological characteristics, colonising valuable shallow habitats. Specimens where collected from habitats at different degree of thermal variability throughout the Sicily: shallow waters (Stagnone di Marsala and Vendicari lagoons), some typical intertidal marine substrates and from pillars of a power plant (T. Imerese). Geometric morphometric analysis carried out on 248 specimens by means the MakeFan6 and MophoJ 1.01 softwares allowed us to individuate differences in the shell shape. Significant differences of morphotypes appeared to be variable with temperature in that shallow specimens formed a significant distinct cluster respect to marine organisms although we detected a partial overlapping among them, while power plant specimens were at all different from all other mussels.

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., peer-reviewed