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).Key words. -Bathyporeia, geometric morphometry, eastern Mediterranean RIASSUNTO Individui di Bathyporeia guilliamsoniana (Spence Bate, 1857), campionati nel Mediterraneo orientale, sono risultati essere di particolare interesse per il polimorfismo fortemente accentuato nella forma di alcuni caratteri. Non a caso, recentemente il genere è stato oggetto di una revisione che ha messo in luce la presenza di morfotipi, fino a quel momento considerati ascrivibili al rango di specie. Nel presente lavoro l'approccio di morfometria geometrica viene portato come esempio di metodologia utile alla individuazione di quella variazione 'criptica' che spesso influenza la corretta identificazione delle specie. Su oltre cento individui, la profondità dell'incavo nell'angolo postero-distale del terzo epimero è stata messa in relazione con la lunghezza degli individui, senza discriminare raggruppamenti. I risultati supportano le forme sunnivae e megalops morfotipi di Bathyporeia guilliamsoniana in accordo con d'Udekem d' Acoz & Vader (2005).Parole chiave. -Bathyporeia, morfometria geometrica, Mediterraneo orientale

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 Aliquò). Keywords Sandy beaches Á Phaleria spp. Á Central Mediterranean Á Species delimitation Á Molecular systematics Á Geometric morphometrics Communicated by A. Schmidt-Rhaesa.