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a b s t r a c tOur comprehension of the phylogeny and diversity of most inland-water crustaceans is currently hampered by their pronounced morphological bradytely, which contributed to the affirmation of the ''Cosmopolitanism Paradigm'' of freshwater taxa. However, growing evidence of the existence of cryptic diversity and molecular regionalism is available for calanoid copepods, thus stressing the need for careful morphological and molecular studies in order to soundly investigate the systematics, diversity and distribution patterns of the group.Diaptomid copepods were here chosen as model taxa, and the morphological and molecular diversity of the species belonging to the west-Mediterranean diaptomid subgenus Occidodiaptomus were investigated with the aim of comparing the patterns of morphological and molecular evolution in freshwater copepods. Three species currently lumped under the binomen Hemidiaptomus (Occidodiaptomus) ingens and two highly divergent clades within H. (O.) roubaui were distinguished, thus showing an apparent discordance between the molecular distances recorded and Occidodiaptomus morphological homogeneity, and highlighting a noteworthy decoupling between the morphological and molecular diversity in the subgenus.Current Occidodiaptomus diversity pattern is ascribed to a combined effect of ancient vicariance and recent dispersal events. It is stressed that the lack of sound calibration points for the molecular clock makes it difficult to soundly temporally frame the diversification events of interest in the taxon studied, and thus to asses the role of morphological bradytely and of accelerated molecular evolutionary rates in shaping the current diversity of the group.

Using virtually range-wide sampling for three pond turtle taxa (Emys orbicularis galloitalica,\ud E. o. hellenica, E. trinacris), we analyse gene flow across their southern Italian contact zone.\ud Based on population genetic analyses of 15 highly polymorphic microsatellite loci and a\ud mitochondrial marker, we show that the general genetic pattern matches well with the current\ud taxon delimitation. Yet, single individuals with conflicting genetic identity suggest\ud translocation of turtles by humans. In addition, we identify in south-western France and the\ud vicinity of Rome populations being heavily impacted by introduced turtles. Cline analyses\ud reveal that the major genetic break between E. o. galloitalica and E. o. hellenica corresponds\ud well with the currently accepted intergradation zone in southern Italy. However, introgression\ud is largely unidirectional from E. o. galloitalica into E. o. hellenica. In the distribution\ud range of the latter subspecies, genetic footprints of E. o. galloitalica are evident along most\ud of the Italian east coast. Our results corroborate that E. o. galloitalica was introduced long\ud ago in Corsica and Sardinia and naturalized there. Gene flow between E. orbicularis and\ud E. trinacris is negligible, with the Strait of Messina matching well with the narrow cline centre\ud between the two species. This contrasts with other Mediterranean freshwater turtle species\ud with extensive transoceanic gene flow. Compared to the two subspecies of E. orbicularis,\ud the Sicilian E. trinacris shows an unexpectedly strong population structuring, a finding\ud also of some relevance for conservation. The differences between the two taxon pairs\ud E. orbicularis/E. trinacris and E. o. galloitalica/E. o. hellenica support their current taxonomic\ud classification and make them attractive objects for follow-up studies to elucidate the\ud underlying mechanisms of speciation by comparing their propertie

The European pond turtle (Emys orbicularis) is a Nearctic element in the African fauna and thought to have invaded North Africa from the Iberian Peninsula. All North African populations are currently identified with the subspecies E. o. occidentalis. However, a nearly range-wide sampling in North Africa used for analyses of mitochondrial and microsatellite DNA provides evidence that only Moroccan populations belong to this taxon, while eastern Algerian and Tunisian pond turtles represent an undescribed distinct subspecies. These two taxa are most closely related to E. o. galloitalica with a native distribution along the Mediterranean coast of northern Spain through southern France to western and southern Italy. This group is sister to a clade comprising several mitochondrial lineages and subspecies of E. orbicularis from Central and Eastern Europe plus Asia, and the successive sisters are E. o. hellenica and E. trinacris. Our results suggest that E. orbicularis has been present in North Africa longer than on the Iberian Peninsula and that after an initial invasion of North Africa by pond turtles from an unknown European source region, there was a phase of diversification in North Africa, followed by a later re-invasion of Europe by one of the African lineages. The differentiation of pond turtles in North Africa parallels a general phylogeographic paradigm in amphibians and reptiles, with deeply divergent lineages in the western and eastern Maghreb. Acknowledging their genetic similarity, we propose to synonymize the previously recognized Iberian subspecies E. o. fritzjuergenobsti with E. o. occidentalis sensu stricto. The seriously imperiled Moroccan populations of E. o. occidentalis represent two Management Units different in mitochondrial haplotypes and microsatellite markers. The conservation status of eastern Algerian pond turtles is unclear, while Tunisian populations are endangered. Considering that Algerian and Tunisian pond turtles represent an endemic taxon, their situation throughout the historical range should be surveyed to establish a basis for conservation measures.

The pattern of morphological and mtDNA cytochrome b diversity of three calanoid copepod species belonging to the diaptomid genus Hemidiaptomus has been investigated with the aim of checking the reliability of the morphological characters currently used for species identification, and the possible presence of cryptic taxa. A sharply different molecular structuring has been observed in the studied species: while Hemidiaptomus amblyodon exhibits a remarkable constancy throughout the European range of its distribution area (maximum inter-populations cytochrome b divergence of 3%), observed distances between presumed conspecific lineages of Hemidiaptomus gurneyi (maximum divergence of 21.5%) and Hemidiaptomus ingens (maximum 19.1%) suggest that under these binomens are in fact included complexes of cryptic, or currently just unrecognized, independent evolutionary lineages. The application of the ''4x rule'' shows that the two lineages singled out within H. ingens are in fact independent evolutionary units, while the complex molecular structure observed in H. gurneyi s.l. could not be resolved based on the currently available data. Applying standard crustacean mtDNA evolutionary rates to the observed divergence values, the separation of the main lineages within both H. ingens and H. gurneyi might dates back to the Miocene; however, it has also to be considered that the rate of mtDNA evolution might be accelerated in copepods, as already observed in other arthropod taxa. Present results gives further evidences of the high potential for copepod speciation with no or little morphological changes, and stress the need of a revision of the most controversial Palaearctic diaptomid genera.

Diaptomid copepods are an important component of biodiversity in inland aquatic ecosystems worldwide but to date little is known about the historical and ecological factors that determined their current distribution. In the present paper, a critical review of the available literature on diaptomid species distribution in the Western Palearctic was performed, and a biogeographical analysis was carried out on the roles that spatial, current environmental, and historical (paleoclimatic) factors played on their actual distribution in this large area. The results show a clear pattern of colonization which is only partially overlapping what has been recently proposed for other terrestrial and aquatic taxa. Disentangling beta diversity into its turnover and nestedness components, we hypothesized a complex post-glacial pattern of recolonization of the higher latitudes, encompassing the importance of extra-Mediterranean refugia in the West (due to mountain chains which represent effective barriers for recolonization coming from the Italian and Iberian peninsulas) and a more typical pattern of postglacial recolonization from southern refugia in the East, where mountain chains are north-south oriented and therefore less effective as barriers.

Quaternary climatic oscillations and geographic barriers have strongly influenced the distribution and diversification of thermophilic species occurring in the Mediterranean Basin. The Western Mediterranean pond turtle, Mauremys leprosa, is widely distributed throughout the Iberian Peninsula, southern France and most of the Maghreb region, with two subspecies currently recognized. In this work, we used 566 samples, including 259 new individuals, across the species range, and sequenced two mitochondrial markers (cytochrome b gene and control region; 163 samples in a concatenated mtDNA dataset) and one nuclear intron (R35; 23 samples representing all identified sublineages) to study the evolutionary history of M. leprosa. We combined phylogenetic methods and phylogeographic continuous diffusion models with spatial analysis. Our results (1) show a high level of genetic structure in Morocco originated during the Pleistocene; (2) reveal two independent population expansion waves from Morocco to Tunisia and to southern Europe, which later expanded throughout the Iberian Peninsula, and (3) identify several secondary contact zones in Morocco. Our study also sheds new light on the role of geographical features (Moroccan mountains ranges and the Strait of Gibraltar) and Pleistocene climatic oscillations in shaping genetic diversity and structure of M. leprosa, and underlines the importance of the Maghreb as a differentiation centre harbouring distinct glacial refugia.

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