Distribution of cicadas of the genus Lyristes (Hemiptera: Cicadidae) in the eastern Mediterranean area

The present study gives an updated overview on the distribution of species of the genus Lyristes Horváth, 1926 in the eastern Mediterranean area. Besides occurring in southern continental Europe, specimens of L. plebejus were also found along the southern Greek mainland and in the western Aegean island of Kithira. Moreover, the new data presented give L. gemellus as a new record for Greece (appearing only along most of the Anatolian coast) as well as for Cyprus. The genus seems to be absent from the Cyclades as well as from the islands of Crete and Karpathos. Therefore, the results revealed a faunal discontinuity between the Greek western and eastern islands in the Aegean Sea. Hence, the persistence of a deep sea barrier between these two groups of islands seems to explain the present distribution of Lyristes species, which is also in accordance with the paleogeography of the area and with the fact that dispersal to more geographically isolated islands might have been virtually impossible for species of this genus.     

Genetic structuring of European anchovy (Engraulis encrasicolus) populations through mitochondrial DNA sequences

Mitochondrial DNA sequence variation in 655?bpfragments of the cytochrome oxidase c subunit I gene, known as the DNA barcode, of European anchovy (Engraulis encrasicolus) was evaluated by analyzing 1529 individuals representing 16 populations from the Black Sea, through the Marmara Sea and the Aegean Sea to the Mediterranean Sea. A total of 19 (2.9%) variable sites were found among individuals, and these defined 10 genetically diverged populations with an overall mean distance of 1.2%. The highest nucleotide divergence was found between samples of eastern Mediterranean and northern Aegean (2.2%). Evolutionary history analysis among 16 populations clustered the Mediterranean Sea clades in one main branch and the other clades in another branch. Diverging pattern of the European anchovy populations correlated with geographic dispersion supports the genetic structuring through the Black Sea-Marmara Sea-Aegean Sea-Mediterranean Sea quad.     

Genome composition and origin of the polyploid Aegean grass Avenula agropyroides (Poaceae)

Aim The Aegean is a hotspot of plant biodiversity, with its island biota harbouring a large number of endemic taxa. To investigate the relationship between biogeography, polyploid speciation and genomics in the Aegean we used the biogeographically isolated highly polyploid eastern Mediterranean grass species Avenula agropyroides (2n = 70) as an example of complicated polyploid origin. Location Mediterranean, Aegean. Methods To clarify the origin of A. agropyroides, we conducted chromosome studies using repetitive DNAs as hybridization probes in fluorescent in situ hybridization experiments, chromosome banding methods and DNA sequence analyses of plasmid‐cloned nuclear ribosomal (nr) ITS1–5.8S–ITS2 DNA. Results Decaploid A. agropyroides had near‐autopolyploid karyotype structure and contained characteristic sequence motifs of nrDNA repeats not encountered in any of the diploids studied. Special repeat types found in one of its accessions (Crete) showed that A. agropyroides originated from a diploid species with a hybrid background. One of the genomes involved was close to both that of extant species (Avenula aetolica, Avenula compressa, Avenula hookeri, Avenula schelliana, Avenula versicolor) distributed mostly in the eastern Mediterranean to Asia and North America and also to the west Mediterranean (Avenula bromoides). The other resembled that of exclusively western Mediterranean species (Avenula albinervis, Avenula levis, Avenula marginata, Avenula sulcata). Main conclusions Avenula agropyroides represents a remarkable polyploid in the eastern Mediterranean, conserving the genome structure of a diploid species that no longer exists. This highlights how the Aegean has been less affected than other Eurasian regions by the repeated shifts of climatic zones and vegetation belts since the Late Tertiary.     

Genetic architecture of the marbled goby Pomatoschistus marmoratus (Perciformes, Gobiidae) in the Mediterranean Sea

The marbled goby Pomatoschistus marmoratus, a species inhabiting coastal Mediterranean lagoons, has been studied by measuring its mitochondrial DNA variation. This analysis revealed a Mediterranean west vs east split and, subsequently, an eastern differentiation among the Libyan-Tunisian Gulf, the Adriatic Sea and the Aegean Sea. The high cohesion between the samples collected in the vast area of western Mediterranean contrasts with the genetic mosaic of the more sub-structured eastern Mediterranean. This western homogeneity can not yet be fully explained even if a human-mediated migratory flow, due to a maritime traffic, has been posited. The pattern in the eastern basin revealed a genetic architecture possibly due to the non-migratory habit of the gobid. Within this perspective, the role of the Mediterranean lagoon habitat should be related to how much it amplifies the effects of historical (e.g. past sea-level changes) and environmental (e.g. present-day hydrographic regime) processes as regards the genetic structure of the inhabiting species.     

Genetic differentiation of Mediterranean horse mackerel (Trachurus mediterraneus) populations as revealed by mtDNA PCR-RFLP analysis

The genetic population structure of Mediterranean horse mackerel, Trachurus mediterraneus , from seven locations throughout the Black, Marmara, Aegean and eastern Mediterranean seas was investigated using restriction fragment length polymorphism (RFLP) analysis of the mtDNA 16S rDNA region. An approximately 2000-bp segment was screened in 280 individuals using six restriction enzymes, resulting in 10 composite haplotypes. The most common haplotype was present in 56.42% individuals; the next most frequent haplotype was present in 22.85% individuals. Average haplotype diversity within samples was moderate (0.38), and nucleotide diversity was low (0.00435). Mean nucleotide divergence for the seven sampling sites was 0.0028. Nucleotide divergence among samples was moderate, with the highest value detected between the Aegean Sea (Izmir) and the eastern Black Sea (Trabzon) populations (0.007055), and the lowest (−0.000043) between the Marmara Sea (Adalar) and the western Black Sea (Sile) populations. In Monte Carlo pairwise comparisons of haplotype frequencies, the Sinop from the middle Black Sea, Trabzon from the eastern Black Sea, and Iskenderun Bay from the north-eastern Mediterranean Sea exhibited highly significant (P   <   0.001) geographical differentiation from each other and from all other populations. Mantel's test indicated that the nucleotide divergence among populations of T. mediterraneus was not significantly associated with their geographical isolation ( r  = −0.2963; P   >   0.05). Consequently, the mtDNA 16S rDNA region provided evidence for the existence of three distinct T. mediterraneus populations (Sinop, Trabzon and Iskenderun Bay) in the Black and north-eastern Mediterranean seas.     

Coastal fish otoliths from the early Pleistocene of Rhodes (eastern Mediterranean)

Coastal fish assemblages are especially vulnerable to environmental changes, but little is known about their evolution through time, mainly due to the scarcity of fossil material from such settings. The aim of this study is to characterize the early Pleistocene coastal fish assemblages of the eastern Mediterranean and to reconstruct the related paleobathymetric and paleoecologic conditions. Based on otolith findings, we identified thirty-seven teleost fish species from three sedimentary outcrops on the northeastern part of Rhodes Island (southeastern Aegean, Greece, Eastern Mediterranean), which have been placed within the Gelasian (early Pleistocene). The stratigraphic distribution of fifteen taxa is expanded for this interval, while five species are reported for the first time as fossils. The otolith assemblages provided paleodepth estimates indicative of shallow coastal environments. The ecosystem consisted mostly of substrates of sand and mud, with significant rocky micro-habitats and underwater vegetation; the climate was subtropical. These data complement existing knowledge on the study area, while providing new information on the composition of the ichthyofauna of the eastern Mediterranean during the Gelasian.     

Occurrence of Diopatra marocensis (Annelida,Onuphidae) in the eastern Mediterranean

The present study deals with the presence of Diopatra marocensis in the eastern Mediterranean. This species is small-sized and inhabited muddy bottom near the opening of rivers or lagoons [salinity range: 33−39‰] in the Aegean and Levantine Seas, and reached a maximum density of 90 ind.m^-2 in Mersin Bay. This species might be an alien species that was introduced from the East Atlantic (near Gibraltar) to the eastern Mediterranean via ballast water of ships, as it has never been reported from the western Mediterranean Sea.     

The species–area relationship in centipedes (Myriapoda: Chilopoda): a comparison between Mediterranean island groups

The present study article examines the shapes of centipede species–area relationships (SARs) in the Mediterranean islands, compares the results of the linear form of the power model between archipelagos, discusses biological significance of the power model parameters with other taxa on the Aegean archipelago, and tests for a significant small‐island effect (SIE). We used 11 models to test the SARs and we compared the quality‐of‐fit of all candidate models. The power function ranked first and Z‐values was in the range 0.106–0.334. We assessed the presence of SIEs by fitting both a continuous and discontinuous breakpoint regression model. The continuous breakpoint regression functions never performed much better than the closest discontinuous model as a predictor of centipede species richness. We suggest that the relatively low Z‐values in our data partly reflect better dispersal abilities in centipedes than in other soil invertebrate taxa. Longer periods of isolation and more recent island formation may explain the somewhat lower constant c in the western Mediterranean islands compared to the Aegean islands. Higher breakpoint values in the western Mediterranean may also be a result of larger distance to the mainland and longer separation times. Despite the differences in the geological history and the idiosyncratic features of the main island groups considered, the overall results are quite similar and this could be assigned to the ability of centipedes to disperse across isolation barriers. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 146–159.     

Patterns of diversity of the north-eastern Atlantic blenniid fish fauna (Pisces: Blenniidae)

This paper presents an analysis of the distributional patterns of blenniids (Pisces: Blenniidae) in the north‐eastern Atlantic. Two peaks of species diversity were found, both in terms of number of species and number of endemics: one in the tropical African coast and another in the Mediterranean Sea. A cluster analysis of similarity values (Jaccard coefficient) among the eastern Atlantic zoogeographical areas, revealed the following groups: a north temperate group, a tropical group formed by the tropical African coast and Mauritania, another group formed by the islands of Cape Verde, a south temperate group (South Africa), and a southern Atlantic group formed by the islands of Ascension and St Helena. Within the north temperate group, the subgroups with higher similarities were: Azores and Madeira, Canary Islands and Morocco, and the Mediterranean and the Atlantic coast of the Iberian Peninsula. Based on affinity indices, the probable directions of faunal flows were inferred. The tropical coast of Africa and the Mediterranean emerged from this analysis as probable speciation centres of the north‐eastern Atlantic blenniid fauna. The Mediterranean may have also acted as a refuge during glacial periods.     

Contemporary geography dominates butterfly diversity gradients within the Aegean archipelago (Lepidoptera: Papilionoidea, Hesperioidea)

Aim We compare the influence of contemporary geography and historical influences on butterfly diversity for islands in the Aegean archipelago. Location The Aegean archipelago (Greece) and two islands (Cyprus and Megisti) in the Levantine Sea. Methods Thirty‐one islands were examined. Data are taken from own surveys (Coutsis and Olivier) and from the literature. Stepwise multiple regression is used to determine relationships between species richness, frequency, rarity and endemicity against potential geographical predictors. Stepwise logit regression is used to determine geographical predictors of species incidence on islands. Inter‐island and inter‐species associations have been examined using multivariate ordination and clustering techniques. Results The Aegean butterfly fauna is characterized by decreasing diversity and rarity, and increasing homogeneity, from the periphery to the present geographical centre of the archipelago (Cyclades). Diversity and rarity are shown to relate closely to species richness, and species richness, in turn, is largely explained by contemporary geography, particularly the degree of isolation from the nearest mainland sources of Greece or Turkey, and island dimensions. Islands towards the centre of the archipelago are characterized by a group of mobile species (n ≥ 20 species) with extensive ranges across Europe; species that would have recolonized Santorini (Thira) following the VI6 eruption there c. 1630 bc . Endemic components, indicative of autochthonous evolutionary events, are few (5% of species are endemic) compared to known sedentary organisms (molluscs and isopods), but exceed those for more mobile animals (i.e. birds); their distribution is mainly confined to large isolated islands along the Aegean arc (i.e. Kriti) and in the Dodecanese group. Main conclusions Contemporary geography, i.e. processes currently operating in ecological time, dominates butterfly diversity gradients (species richness, frequency, rarity and incidence) in the archipelago. Two reasons are suggested to account for the lack of endemism and the pattern of decreasing diversity into the Cyclades. First, relict butterfly elements may have become extinct on all but a few larger islands, particularly from environmental changes since the Neolithic (fire and overgrazing). Second, colonization from the continental landmasses is ongoing with more mobile species transferring even to the most isolated islands.     

Organization of Squamata (Reptilia) assemblages in Mediterranean archipelagos

Mediterranean islands have complex reptile assemblages, but little is known about the factors that determine their organization. In this study, the structure of assemblages of Squamata was evaluated based on their species richness and two measures of phylogenetic diversity (variability and clustering). I evaluated the composition of the assemblages comparing distinct biogeographic subregions within the Mediterranean: Adriatic, Aegean, Balearic, Corsica–Sardinia, Crete, Gulf of Gabés, Ionian Sea, Ligurian Sea, Malta, Sicily, and Tyrrhenian Sea. The effect of island environments and geographical isolation on the diversity metrics was assessed using generalized linear models. The analyses indicated that species richness was mostly influenced by island area and geographical isolation. Assemblages on smaller islands were poorer in species and phylogenetically dispersed, possibly as an effect of interspecific competition. The species composition of the assemblages was determined by similar environmental drivers within the biogeographic subregions, including island area, island elevation, geographical isolation, and aridity. In several subregions, significant patterns of phylogenetic attraction were found in species co‐occurrences, caused by the limits imposed by the island size on large predatory species.     

Crassophyllum thessalonicae sp.n. (Octocorallia, Pennatulacea), from the Aegean Sea

A new pennatulacean species, Crassophyllum thessalonicae sp.n. is described from the Mediterranean (North Aegean Sea). This is the first record of a Crassophyllum Tixier-Duri vault, 1961 species from the Mediterranean Sea. The differences between the new species and C. cristatum Tixier-Durivault, 1961, the other known species of the genus, are discussed, and the genus Crassophyllum is critically compared with the other two related genera Pteroeides Herklots, 1858 and Sarcoptilus Gray, 1848.     

Demosponge distribution in the eastern Mediterranean: a NW–SE gradient

The purpose of this paper was to investigate patterns of demosponge distribution along gradients of environmental conditions in the biogeographical subzones of the eastern Mediterranean (Aegean and Levantine Sea). The Aegean Sea was divided into six major areas on the basis of its geomorphology and bathymetry. Two areas of the Levantine Sea were additionally considered. All available data on demosponge species numbers and abundance in each area, as well as their vertical and general geographical distribution were taken from the literature. Multivariate analysis revealed a NW–SE faunal gradient, showing an apparent dissimilarity among the North Aegean, the South Aegean and the Levantine Sea, which agrees with the differences in the geographical, physicochemical and biological characteristics of the three areas. The majority of demosponge species has been recorded in the North Aegean, while the South Aegean is closer, in terms of demosponge diversity, to the oligotrophic Levantine Sea. The number of studies in the Aegean and Levantine subareas was positively correlated with the number of species recorded within each Aegean subarea. Demosponge species with an Altanto-Mediterranean distribution prevailed in the Aegean and the Levantine. The reduced contribution of the endemic component, as compared to the western Mediterranean, is consistent with the general NW–SE decrease in the number of endemic species in the Mediterranean. Demosponge distribution at the order level showed also a NW–SE gradient, similar to that observed in the entire Atlantic–Mediterranean region, suggesting a warm water affinity. Sublittoral, circalittoral and bathyal zones were clearly distinguishable in the Aegean Sea on the basis of their sponge fauna. The total number of species was an exponential negative function of depth.     

Phylogeography and counter-intuitive inferences in island biogeography: evidence from morphometric markers in the mobile butterfly Maniola jurtina (Linnaeus) (Lepidoptera, Nymphalidae)

Distribution of mobile organisms on near-continent islands is mainly shaped by factors operating over ecological rather geological time. However, the phylogeography of single species has the potential to expose historical factors at work. In the present study, West Mediterranean populations of the butterfly Maniola jurtina are studied using geometric morphometrics. The distribution of the two well established lineages ( Maniola jurtina jurtina in the Atlanto–Mediterranean area and Maniola jurtina janira in the Central–Eastern-Mediterranean area) on 12 islands and the adjoining continents are compared. The south-western lineage unexpectedly occurs on islands close to shores occupied by the eastern lineage. We have modelled the distribution of the lineages using three different hypotheses: (1) a contemporary isolation model, which predicts lineage occupancy of islands is linked to relative distances from neighbouring continental areas; (2) a refugial hypothesis, which predicts one lineage to be the ancestral one for the whole region studied, and then successively replaced over part of it; (3) a changing geography hypothesis, which predicts the two lineages to have evolved in their currently occupied areas, continuously sourcing islands subsequent to the Würm maximum glaciation. Of the three models, the refugial hypothesis is most highly correlated with the observed pattern, suggesting that Mediterranean islands may function as refugia during cold periods, much as the three mainland peninsulas of Iberia, Italy and Greece are known to have done. Thereafter, hybridization on the nearest and smallest islands has occurred, with the entire process supporting the notion of the joint influence of factors in ecological and geological time.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 677–692.     

From sampling stations to archipelagos: investigating aspects of the assemblage of insular biota

Aim To investigate the formation of nestedness and species co‐occurrence patterns at the local (sampling station), the intermediate (island group), and the archipelago scale. Location The study used data on the distribution of terrestrial isopods on 20 islands of the central Aegean (Greece). These islands are assigned to two distinct subgroups (Kyklades and Eastern islands). Methods The Nestedness Temperature Calculator was used to obtain nestedness values and maximally nested matrices, the EcoSim7 software and a modified version of Sanderson (2000 ) method were used for the analysis of species co‐occurrences. Idiosyncratic temperatures of species and the order of species placement in the maximally nested matrices were used for further comparisons among spatial scales. The relationships of nestedness values with beta‐diversity, habitat diversity and a number of ecological factors recorded for each sampling station were also investigated. Results Significant nestedness was found at all spatial scales. Levels of nestedness were not related to beta‐diversity or habitat diversity. Nestedness values were similar among spatial scales, but they were affected by matrix size. The species that contributed most to the nested patterns within single islands were not the same as those that produce nestedness at the archipelago scale. There was significant variation in the frequency of species occurrence among islands and among spatial scales. There was no direct effect of ecological factors on the shaping of patterns of nestedness within individual islands, but habitat heterogeneity was crucial for the existence of such patterns. Positive associations among species prevailed at all scales when species per station were considered, while negative associations prevailed in the species per island matrices. All associations resulted from the habitat structure of sampling stations and from particularities of geographical distributions. Conclusions There was no clear‐cut distinction between nestedness patterns among spatial scales, even though different species, and partially different factors, contributed to the formation of these patterns in each case. There was a core of species that contributed to the formation of nested patterns at all spatial scales, while the patterns of species associations suggested that biotic interactions are not an important causal factor. The results of this study suggest that locally rare species cannot be widespread at a higher spatial scale, while locally common species can have a restricted distribution.     

Inference of a radiation in Mastus (Gastropoda, Pulmonata, Enidae) on the island of Crete

The Mediterranean land snail genus Mastus (Beck, 1837) is highly divergent. Thirty-two Mastus species have been recorded throughout the genus range, and 23 of them are endemic to the islands of the Aegean Sea and mainland Greece. Of these, all 16 Mastus species reported from Crete are endemic to this island. A robust molecular phylogenetic framework based on mitochondrial and nuclear genes (1623 bp) allowed us to explore the temporal diversification pattern of lineages, using molecular clock approaches. Our results showed an initial radiation in the evolutionary history of the Cretan lineage, followed by a subsequent slowdown of lineage splitting rate. Using a dated major vicariant event of the Aegean area, we estimated the absolute time of the radiation event and proposed a biogeographic scenario accounting for the observed pattern. Additionally, we tried to infer the processes that led to the divergence of the Cretan Mastus species, by applying comparative methods in phylogenetically informated context. Overall, our results favoured a nonecological radiation scenario in the Cretan Mastus species due to an allopatric divergence of secondary sexual characters.     

Molecular phylogeny of the Greek legless skink Ophiomorus punctatissimus (Squamata: Scincidae): the impact of the mid-Aegean trench in its phylogeography

Sequence data derived from three mitochondrial markers (cytochrome b, 16S rRNA and 12S rRNA genes) were used to infer the evolutionary history of several insular and mainland populations of the Greek legless skink (Ophiomorus punctatissimus), covering most of its distributional range. All phylogenetic analyses produced topologically identical trees that revealed a well-resolved phylogeny. These trees support two O. punctatissimus clades, which are geographically separated (west and east of the mid-Aegean trench). The assumption of a clock-like evolution could not be rejected, and thus a local clock was calibrated for the O. punctatissimus lineages. The non-overlapping geographic distributions of the major clades suggest a spatial and temporal sequence of diversification that coincides with paleogeographic separations during the geological history of the Aegean region. It seems that O. punctatissimus is an old eastern Mediterranean species that has been differentiating in this region at least from middle Miocene. It is possible that the ancestral form of O. punctatissimus invaded the Aegean region from Anatolia before the complete formation of the mid-Aegean trench, when the Aegean was still a uniform landmass, while other vicariant events have led to its present distribution.     

Molecular phylogeography of Troglophilus cave crickets (Orthoptera,Rhaphidophoridae): A combination of vicariance and dispersal drove diversification in the East Mediterranean region

In this study, we investigated the molecular phylogenetic divergence and historical biogeography of cave crickets belonging to the genus Troglophilus (Orthoptera, Rhaphidophoridae) from caves in eastern Mediterranean and Anatolia regions. Three mitochondrial DNA genes (COI, 12S rDNA, and 16S rDNA) and two nuclear ones (18S rDNA and 28S rDNA) were amplified and partially sequenced to reconstruct phylogenetic relationships among most of the known Troglophilus species. Results showed a well‐resolved phylogeny with three main clades representing the Balkan, the Anatolian, and the Cycladian–Cretan lineages. Based on Bayesian analyses, we applied a relaxed molecular clock model to estimate the divergence times between these three lineages. Dating estimates indicate that radiation of the ingroup might have been triggered by the opening of the Mid‐Aegean trench, while the uplift of the Anatolian Plateau in Turkey and the changes of relief, emergence, and disappearance of orographic and hydrographical barriers in the Balkan Peninsula are potential paleogeographic events responsible for the initial diversification of the genus Troglophilus. A possible biogeographic scenario, reconstructed using S‐DIVA with RASP software, suggested that the current distribution of Troglophilus species can be explained by a combination of both dispersal and vicariance events that occurred in particular in the ancestral populations. The radiation of Troglophilus species likely started from the Aegean and proceeded eastward to Anatolia and westward to the Balkan region. Results are additionally compared to those available for Dolichopoda, the only other representative genus of Rhaphidophoridae present in the Mediterranean area.     

EASTERN MEDITERRANEAN OPISTHOBRANCHIA: ELYSIIDAE (SACOGLOSSA = ASCOGLOSSA)

An account is given of the elysiid sacoglossans collected ondiving expeditions to the eastern Mediterranean shores of Yugoslaviaand Greece during the period 1978–1986, supplemented bymaterial collected around Naples and some preserved specimensfrom other Mediterranean localities. In all, 6 species of Elysiaand 1 of Bosellia were investigated, including one new to science,E. gordanae from the Yugoslav Istrian Peninsula. The enigmaticElysia translucens Pruvot-Fol, 1957 was found in the easternbasin for the first time. The presence of the Bermudan, CanaryIslands and Jamaican E. flava Verrill, 1901 was confirmed inthe Greek Ionian and Aegean Seas, as well as in the Gulf ofCorinth. The geographical ranges of the other species were extendedby these collections from the eastern basin. The 7 elysiid specieswere illustrated from life and the radulae compared; great differencesin the size, shape and denticulation of the teeth of the differentspecies were evident (Received 8 May 1987;