The Mediterranean species of genus Loxosceles Heineken amp; Lowe, 1832 (Araneae: Sicariidae): Loxosceles imazighen sp. n. from Morocco and first description of the female of L. mrazig Ribera amp; Planas, 2009 from Tunisia.

The aim of this paper is to describe a new species of the genus Loxosceles Heineken Lowe, 1832 from Morocco, Loxosceles imazighen sp. n., and to describe for the first time a female of Loxoxceles mrazig Ribera Planas, 2009 from Tunisia. Both species live in xeric and desert environments and are located in southern Atlas Range. Molecular phylogenetic analyses, using mitochondrial (cox1, 16S) and nuclear (H3, 28S) markers, revel that these species are closely related and that they constitute a separate evolutionary lineage of L. rufescens (Dufour, 1820) and of the set of endemic species of the Canary Islands. L. imazighen sp. n. differs from L. mrazig, the closest species morphologically and geographically, in the shapes and proportions of the male palpal tibia and the shapes and dispositions of the female seminal receptacles. In addition, L. mrazig females show morphological variability in their genitalia, mainly in the inner and outer lobes. Although that variability cannot be associated with different populations, since it also appears within individual populations, and is not related to genetic or geographic distances.

The Mediterranean as a melting pot: Phylogeography of Loxosceles rufescens (Sicariidae) in the Mediterranean Basin.

The species Loxosceles rufescens is native to the Mediterranean but considered cosmopolitan because it has been dispersed worldwide. A previous study revealed 11 evolutionary lineages across the Mediterranean, grouped into two main clades, without any clear phylogeographic pattern. The high genetic diversity within this species (p-distances of up to 7.8% in some Mediterranean lineages), together with the results obtained with different species delimitation methods (GMYC, TCS) could indicate the existence of cryptic species. Here we compare the mitochondrial and microsatellite diversity to elucidate if the lineages of L. rufescens in the Mediterranean should be considered different species (cryptic species) or populations of the same species. To do so, we analyzed the cox1 diversity of 196 individuals, of which, we genotyped 148, sampled from 19 localities across the Mediterranean. STRUCTURE analyses of microsatellite data identified two genetic clusters of L. rufescens. One cluster included individuals from Western Mediterranean localities (Iberian Peninsula, Morocco, Balearic Islands) and Israel, while the second one grouped individuals from Italian and Greek localities, including Sardinia, Sicily and Tunisia. These patterns suggest that geographic proximity is the more significant factor in the clustering with microsatellite data and shows the existence of gene flow between the nearest geographic areas, even if the individuals belong to different mitochondrial lineages or clades. The lack of correspondence between both genetic markers suggests that the evolutionary lineages found within L. rufescens should not be considered different species. We conclude that these phylogenetic linages and their distribution may be the result of the maternal evolutionary history of the species and human-mediated dispersion.