Saturnius minutus n. sp. and S. dimitrovi n. sp. (Digenea: Hemiuridae) from Mugil cephalus L. (Teleostei: Mugilidae), with a multivariate morphological analysis of the Mediterranean species of Saturnius Manter, 1969

Three species of the bunocotyline genus Saturnius Manter, 1969 are described from the stomach lining of mugilid fishes of the Mediterranean and Black Seas. Two of the species are new: S. minutus n. sp. occurs in Mugil cephalus off the Mediterranean coast of Spain; and S. dimitrovi n. sp., a parasite of M. cephalus off the Bulgarian Black Sea coast and the Spanish Mediterranean coast, was originally described as S. papernai by Dimitrov et al. (1998). In addition, S. papernai Overstreet, 1977 is redescribed from M. cephalus off the Spanish Mediterranean coast and from Liza aurata and L. saliens off the Bulgarian Black Sea coast. The three species are distinguished morphometrically using univariate and multivariate analyses. These results were verified using Linear Discriminant Analysis which correctly allocated all specimens to their species designations based on morphology (i.e. 100% successful classification rate) and assigned almost all specimens to the correct population (locality). The following variables were selected for optimal separation between samples: the length of the forebody, ventral sucker and posterior testis, the length and width of the posteriormost pseudosegment, and the width of the muscular flange at ventral sucker level.     

Characterization of microsatellite loci in the dwarf eelgrass Zostera noltii (Zosteraceae) and cross‐reactivity with Z. japonica

Zostera noltii is an important species of eelgrass occurring along European, north African, Mediterranean, Black Sea and Azov Sea coasts. Nine microsatellite loci were developed and no linkage disequilibrium was observed. Cross‐amplification was observed for all loci (polymorphic) in Z. japonica; only four loci amplified (monomorphic) in Z. marina.     

Magnibursatus caudofilamentosa (Reimer, 1971) n. comb. (Digenea: Derogenidae) from the stickleback Gasterosteus aculeatus L. in Danish waters: a zoogeographical anomaly?

The adult of Magnibursatus caudofilamentosa (Reimer, 1971) n. comb. is described from the stickleback Gasterosteus aculeatus in eastern Danish waters. Its larval form, Cercaria caudofilamentosa Reimer, 1971, develops in the prosobranch mollusc Rissoa membranacea. It is distinguished from its only congener, M. skrjabini (Vlasenko, 1931) from gobiids in the Black Sea, by several features, including the thick, heavily muscled nature of the wall of the sinus-sac. The zoogeography of halipegine derogenids in fishes is discussed. The group is considered to have a distribution which reflects the extent of the ancient Tethys Sea: in this respect, the finding of Magnibursatus in Danish waters is an anomaly.     

Phylogenetic analysis of the north‐east Atlantic and Mediterranean species of the genus Stenosoma (Isopoda,Valvifera, Idoteidae)

Xavier, R., Santos, A. M., Harris, D. J., Sezgin, M., Machado, M., Branco, M. (2012). Phylogenetic analysis of the north‐east Atlantic and Mediterranean species of the genus Stenosoma (Isopoda, Valvifera, Idoteidae). —Zoologica Scripta, 41, 386–399. The marine isopod genus Stenosoma is widespread in the northern hemisphere. However, 12 of its 14 known species are found within the Mediterranean basin and adjacent regions of the north‐east Atlantic and the Black Sea. Such a high level of diversity confined to a limited region of a much larger circumglobal distribution suggests that the Mediterranean region may have played a crucial role in the evolutionary history of this genus. In the present work, the phylogeny of the genus Stenosoma was investigated on the basis of DNA sequencing data from one nuclear (28SrRNA) and two mitochondrial (COI, ND4) gene fragments obtained for nine of 12 Atlantic–Mediterranean species. Divergence time estimates point to a Tethyan origin of Stenosoma and suggest that the speciation events from which stem most of the extant species took place well before the Messinian Salinity Crisis. Stenosoma spinosum and Stenosoma appendiculatum are the only exceptions, as they apparently arose within the Mediterranean during the Pleistocene. Phylogenetic reconstruction agrees with current taxonomic status of most species. However, Stenosoma capito clustered in two distinct and well‐supported clades, one composed of eastern Mediterranean and Black Sea specimens and the other by western Mediterranean and Atlantic ones. Such polyphyly suggests the existence of a previously unrecognized species, Stenosoma sp., which so far has been confounded with S. capito.     

The taxonomic status of the Black Sea and Marmara Sea populations of the Broadnosed Pipefish Syngnathus cf. argentatus Pallas (Teleostei: Syngnathidae) based on morphological and molecular characters

As the Black Sea and Marmara Sea population of the Broadnosed Pipefish Syngnathus cf. argentatus show some morphological differences from the Mediterranean Sea populations, some authors regard it as an endemic species Syngnathus argentatus Pallas, 1814, while others consider it as a synonym of S. typhle Linnaeus, 1758. The aim of this study is to compare the populations of the Black Sea and Sea of Marmara with the Aegean Sea population, using a combination of morphological and molecular characters, in order to clarify their taxonomic status. Sampling was carried out at three stations in the Black Sea, two in the Sea of Marmara and three in the Aegean Sea, and a total of 24 morphometric and 6 meristic characters were examined. Metric data were analysed by Principal Component Analysis (PCA) and phylogenetic relationships between the populations were analysed using both cytochrome oxidase subunit 1 (COI) gene and cytochrome b (cyt-b) gene sequences. Although constant differences were observed in snout depths between the Black Sea/Marmara Sea and the Aegean Sea populations, other morphological features and genetic analysis did not enable these populations to be differentiated. These findings indicate that S. argentatus is a synonym of S. typhle.     

The relationship between somatic growth and otolith dimensions of Mediterranean horse mackerel (Trachurus mediterraneus) from the Black Sea

In this study the relationships between somatic growth and otolith dimensions of Mediterranean horse mackerel (Trachurus mediterraneus) were investigated from samples obtained in the southeastern Black Sea area. It was concluded that there is a significant relationship between fish size and otolith dimensions. Therefore, age of Mediterranean horse mackerel can be estimated from otolith length and weight with sufficient certainty. This research was the first study of these relationships for T. mediterraneus from the Black Sea.     

Rhipidocotyle genovi n. sp. (Digenea: Bucephalidae) from the intestine ofGaidropsarus mediterraneus (L.) (Gadiformes: Gadidae) from the Black Sea

Rhipidocotyle genovi n. sp. is described from the fishGaidropsarus mediterraneus (L.) (Gadiformes: Gadidae) in the Black Sea. Morphological features characteristic of this species include: an anterior sucker with seven prominent muscular appendages; a pharynx rather posterior in position; ovary and testes relatively anterior in position, usually anterior to the pharynx; a long (in relation to body length) sucker, cirrus-sac and excretory vesicle; the presence of a pre-oral lip; and contiguous vitelline fields which form an arch. The new species is distinguished fromR. galeata, R. lamberti andBucephalus marinum. This is the first member of the genus whose adults are recovered from Black Sea marine fishes. Metacercariae, which encyst in large numbers in the musculature and fins of the blenniid fishesBlennius tentacularis, B. sanguinolentus, B pavo, B. sphinx andB. zvonimiri and exhibit a similar morphology to the adult, are described.     

Blooms of the invasive ctenophore, <Emphasis Type="Italic">Mnemiopsis</Emphasis> <Emphasis Type="Italic">leidyi</Emphasis>, span the Mediterranean Sea in 2009

Blooms of the invasive ctenophore, Mnemiopsis leidyi, occurred in 2009 along the Mediterranean Sea coasts of Spain and Israel. This voracious zooplanktivore spread throughout the Black Sea basin after its introduction in the early 1980s, throughout northern European coastal waters, and now occurs throughout the Mediterranean Sea. M. leidyi occurred throughout the summer along the entire Catalan Spanish and Israeli coasts in 2009. Those locations had high temperatures (18–26°C) and salinities (37–38) during the blooms. The patterns of abundance of large jellyfish along the Catalan coast were unusual in 2009, with low numbers during July, August, and September when ctenophores were abundant. Small populations of those potential predators and food competitors of M. leidyi could have contributed to the ctenophore bloom. The identity of the ctenophores from Spain and Israel was confirmed as M. leidyi by molecular analysis based on DNA sequencing of the nuclear internal transcribed spacer (ITS) regions. This is the first molecular confirmation of M. leidyi in the Mediterranean Sea. Most ctenophores had an ITS genotype previously found in M. leidyi from other invaded regions (the Black, Azov, and Mediterranean seas), as well as native regions in the United States, suggesting common ancestry. Based on the circulation patterns of Mediterranean surface waters and shipping activities, we conclude that the spread of M. leidyi in the Mediterranean probably resulted from re-introductions by ballast water transport and subsequent distribution by currents. We also conclude that the near-simultaneous blooms in opposite ends of both the Mediterranean basins indicate that M. leidyi is resident around the Mediterranean. We discuss environmental conditions, food, and predators of M. leidyi in both regions that would influence the future effects of this voracious consumer on the pelagic food web of the Mediterranean Sea.     

Munnogonium affinissp. n.: A New Species of Isopod (Asellota: Paramunnidae) from the Coast of Korea,Sea of Japan

The new species Munnogonium affinisfrom the coast of Korea (the Sea of Japan) is described. This is the first record of the genus Munnogoniumfrom the western Pacific. The new species differs considerably from the four eastern Pacific American species of this genus and is most similar to M. maltiniifrom the Mediterranean Sea.     

New records of rare derogenids (Digenea: Hemiuroidea) from Mediterranean sparids,including the description of a new species of <Emphasis Type="Italic">Magnibursatus</Emphasis> Naidenova, 1969 and redescription of <Emphasis Type="Italic">Derogenes adriaticus</Emphasis> Nikolaeva, 1966

Records of derogenid digeneans in the Mediterranean and Black Sea region are scarce and tend to be restricted to a small number of host-groups, but especially to sparid fishes. This work reports on the presence of derogenine and halipegine derogenids from two sparids, Diplodus annularis (L.) and D. sargus (L.), from off the Mediterranean coast of Spain. Five derogenid forms were recovered. Derogenes adriaticus Nikolaeva, 1966 is redescribed from Diplodus annularis, and Derogenes sp. is described from the same host but differentiated from the former species. Magnibursatus barretti n. sp. is described from Diplodus sargus and distinguished from other species of the genus especially by its smaller body size and smaller eggs. M. bartolii Kostadinova, Power, Fernández, Balbuena, Raga & Gibson, 2003 is redescribed from D. sargus, a new host for this species. A single specimen from D. sargus, somewhat similar to M. minutus Kostadinova, Power, Fernández, Balbuena, Raga & Gibson, 2003, is also described, as it exhibits some morphometric differences from the latter species.     

Endemic and Indo-Pacific plankton in the Mediterranean Sea: a study based on dinoflagellate records

Aim To investigate biogeographical patterns based on published dinoflagellate records from the Mediterranean and Black Seas, and to provide a tentative list of endemic and Indo‐Pacific dinoflagellates in the Mediterranean Sea. Location Mediterranean Sea, Black Sea. Methods Checklists of dinoflagellates of the Mediterranean and Black Seas were compared with worldwide literature records. Only species reported in the Indo‐Pacific Ocean or exclusively known in the Mediterranean Sea were selected for biogeographical analysis. Results Dinoflagellates in the Mediterranean Sea comprised c. 43% of the world marine species and c. 88% of the dinoflagellate genera. Species richness among the Mediterranean sub‐basins showed marked differences due to the less reliable records of unarmoured (athecate) and rare dinoflagellates. These differences disappeared when only the more easily identifiable taxa were considered. Of the 673 dinoflagellates cited in the Mediterranean, 87% were also reported in the Atlantic Ocean. Only 40 taxa (6% of the total) were considered to be potential Indo‐Pacific species. Most were reported from the Ligurian Sea (21), and only two species from the Levantine basin. The other 48 taxa (7% of total) were known exclusively from the Mediterranean Sea, mainly from the Ligurian Sea. Half of these taxa were reported by a single author. Main conclusions Substantial dinoflagellates species richness can be attributed, in part, to the historical tradition of taxonomic studies in the Mediterranean Sea. The list of species of both Indo‐Pacific and exclusively Mediterranean species included taxa of dubious taxonomic validity or that were insufficiently known. The exclusion of these questionable taxa revealed the near absence of endemic dinoflagellates in the Mediterranean Sea compared with macroscopic organisms. This could be related to: (1) continuous replenishment of the plankton populations by the inflow of Atlantic water through the Strait of Gibraltar, (2) the possibility that species introduced during the Pliocenic flooding after the Messinian salinity crisis have not had enough time to diverge from their Atlantic ancestors, and/or (3) the reliance on traditional taxonomy based on morphological characters, which precludes the detection of cryptic speciation.     

Invasion Pathway of the Ctenophore Mnemiopsis leidyi in the Mediterranean Sea

Gelatinous zooplankton outbreaks have increased globally owing to a number of human-mediated factors, including food web alterations and species introductions. The invasive ctenophore Mnemiopsis leidyi entered the Black Sea in the early 1980s. The invasion was followed by the Azov, Caspian, Baltic and North Seas, and, most recently, the Mediterranean Sea. Previous studies identified two distinct invasion pathways of M. leidyi from its native range in the western Atlantic Ocean to Eurasia. However, the source of newly established populations in the Mediterranean Sea remains unclear. Here we build upon our previous study and investigate sequence variation in both mitochondrial (Cytochrome c Oxidase subunit I) and nuclear (Internal Transcribed Spacer) markers in M. leidyi, encompassing five native and 11 introduced populations, including four from the Mediterranean Sea. Extant genetic diversity in Mediterranean populations (n = 8, N _a = 10) preclude the occurrence of a severe genetic bottleneck or founder effects in the initial colonizing population. Our mitochondrial and nuclear marker surveys revealed two possible pathways of introduction into Mediterranean Sea. In total, 17 haplotypes and 18 alleles were recovered from all surveyed populations. Haplotype and allelic diversity of Mediterranean populations were comparable to populations from which they were likely drawn. The distribution of genetic diversity and pattern of genetic differentiation suggest initial colonization of the Mediterranean from the Black-Azov Seas (pairwise F _ST = 0.001–0.028). However, some haplotypes and alleles from the Mediterranean Sea were not detected from the well-sampled Black Sea, although they were found in Gulf of Mexico populations that were also genetically similar to those in the Mediterranean Sea (pairwise F _ST = 0.010–0.032), raising the possibility of multiple invasion sources. Multiple introductions from a combination of Black Sea and native region sources could be facilitated by intense local and transcontinental shipping activity, respectively.     

An integrative systematic approach to species diversity and distribution in the genus Mesophyllum (Corallinales,Rhodophyta) in Atlantic and Mediterranean Europe

For the first time, a comprehensive assessment of Mesophyllum species diversity and their distribution in Atlantic Europe and the Mediterranean Sea is presented based on molecular (COI-5P, psbA) and morphological data. The distribution ranges were redefined for the four species collected in this study: M. alternans, M. expansum, M. macroblastum and M. sphaericum. Mesophyllum sphaericum, which was previously known only from a single maerl bed in Galicia (NW Spain), is reported from the Mediterranean Sea. The known range of M. expansum (Mediterranean and Macaronesia) was extended to the Atlantic Iberian Peninsula. The occurrence of M. alternans was confirmed along the Atlantic French coast south to Algarve (southern Portugal). Mesophyllum lichenoides was only recorded from the Atlantic, whereas M. macroblastum appears to be restricted to the Mediterranean Sea. A positive correlation was observed between maximum Sea Surface Temperature (SSTmax) and the depth at which M. expansum was collected, suggesting that this species may compensate for higher SST by growing in deeper habitats where the temperature is lower. The latter indicates that geographic shifts in the distribution of coastal species as a result of global warming can possibly be mitigated by changes in the depth profile at which these species occur. Mesophyllum expansum, an important builder of Mediterranean coralligenous habitats, may be a good target species to assess its response to climate change.     

The occurrence of two xanthochromic fish,Epiniphelus marginatus (Serranidae) and Diplodus vulgaris (Sparidae) (Osteichthyes) in the eastern Mediterranean

Xanthism in fishes has a genetic basis that causes abnormal skin colouration of yellow to orange-gold. Xanthochromic specimens are rare in nature. We report two cases of adult xanthochromic specimens from the Mediterranean Sea: Epinephelus marginatus from Israel and Diplodus vulgaris from Greece and discuss the reason for the paucity of reports of xanthochromic fish from the Mediterranean.     

Modelling potential habitat of the invasive ctenophore <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis> in Aegean Sea

The invasive ctenophore Mnemiopsis leidyi was accidentally introduced into the Black Sea in the early 1980s and it was first sighted in the Aegean Sea (Eastern Mediterranean) in the early 1990s. This article presents a first attempt to develop a predictive spatial model based on M. leidyi presence data and satellite environmental data from the Aegean Sea during early summer, in order to identify those areas in the Greek Seas and the entire Mediterranean basin that could serve as potential habitat for the species. Generalized additive models (GAM) were applied. The final GAM model indicated higher probability of finding M. leidyi present in depths of 65–135 m and sea surface temperature values of 21–25°C. Furthermore, the significant interaction between photosynthetically active radiation (PAR) and sea level anomaly (SLA) indicated a higher probability of M. leidyi presence in low values of PAR and SLA. In the next step, the final GAM was applied in a prediction grid of mean monthly satellite values for June 2004–2006 in order to estimate probability of M. leidyi presence in the Hellenic Seas and the whole Mediterranean basin at a GIS resolution of 4 km. In the Aegean Sea, species potential habitat included areas influenced by the Black Sea Water (e.g. Thracian Sea, Limnos-Imvros plateau), gulfs that are affected by river runoffs, such as the Thermaikos, Strymonikos and Patraikos gulfs, or areas with strong anthropogenic influence such as the Saronikos gulf. Areas with the same environmental conditions as those in Aegean Sea have been indicated in certain spots of the Levantine Sea as well as in coastal waters of Egypt and Libya, although their spatial extent varied largely among years examined. However, the occurrence of conditions that are linked to high probability of M. leidyi presence does not necessarily mean that these areas can support successful reproduction, high population or bloom levels, since these depend on a combination of temperature, salinity, food availability and the abundance of predators. Guest editor: V. D. Valavanis Essential Fish Habitat Mapping in the Mediterranean     

Taxonomy of Oncaeidae (Copepoda,Poecilostomatoida) from the Red Sea. III. Morphology and phylogenetic position of Oncaea subtilis Giesbrecht, 1892

Both sexes of Oncaea subtilis Giesbrecht, 1892, a small oncaeid species commonly occurring in temperate and tropical regions, are redescribed on the basis of material from the Red Sea. It is placed in a new monotypic genus, Monothula, on the basis of the loss of the outer spine on the third segment of the endopod of legs 2–4, and the presence of a single dorsal egg-sac, which is attached medially to the genital double-somite. The latter character is unique among oncaeids. The geographical distribution of M. subtilis comb. nov. is reviewed, and additional taxonomic data based on material from the eastern Mediterranean, the Arabian Sea and the eastern Indian Ocean are presented. The phylogenetic relationships of M. subtilis within the Oncaeidae are discussed.     

The ctenophore Mnemiopsis in native and exotic habitats: U.S. estuaries versus the Black Sea basin

The native habitats of the ctenophore, Mnemiopsis, are temperate to subtropical estuaries along the Atlantic coast of North and South America, where it is found in an extremely wide range of environmental conditions (winter low and summer high temperatures of 2 and 32 °C, respectively, and salinities of <2–38). In the early 1980s, it was accidentally introduced to the Black Sea, where it flourished and expanded into the Azov, Marmara, Mediterranean and Caspian Seas. We compile data showing that Mnemiopsis has high potentials of growth, reproduction and feeding that enable this species to be a predominant zooplanktivore in a wide variety of habitats; review the population distributions and dynamics of Mnemiopsis in U.S. waters and in the Black Sea region; and examine the effects of temperature and salinity, zooplankton availability and predator abundance on Mnemiopsis population size in both regions, and the effects of Mnemiopsis on zooplankton, ichthyoplankton and fish populations, focusing on Chesapeake Bay and the Black Sea. In both regions, Mnemiopsis populations are restricted by low winter temperatures (<2 °C). In native habitats, predators of Mnemiopsis often limit their populations, and zooplanktivorous fish are abundant and may compete with the ctenophores for food. By contrast, in the Black Sea region, no obvious predators of Mnemiopsis were present during the decade following introduction when the ctenophore populations flourished. Additionally, zooplanktivorous fish populations had been severely reduced by over fishing prior to the ctenophore outbreak. Thus, small populations of potential predators and competitors for food enabled Mnemiopsis populations to swell in the new habitats. In Chesapeake Bay, Mnemiopsis consumes substantial proportions of zooplankton daily, but may only noticeably reduce zooplankton populations when predators of Mnemiopsis are uncommon. Mnemiopsis also is an important predator of fish eggs in both locations. In the Black Sea, reductions in zooplankton, ichthyoplankton and zooplanktivorous fish populations have been attributed to Mnemiopsis. We conclude that the enormous impact of Mnemiopsis on the Black Sea ecosystem occurred because of the shortage of predators and competitors in the late 1980s and early 1990s. The appearance of the ctenophore, Beroe ovata, may promote the recovery of the Black Sea ecosystem from the effects of the Mnemiopsis invasion.     

Acartia tonsa: a species new for the Black Sea fauna

The presence of Acartia tonsa in Black Sea waters (South Crimean coast, Ukraine) is reported for the first time. A. tonsa may be a recently introduced species in the Black Sea. Morphological features of the adults have been shown by S.E.M.     

Morphokaryological variability and divergence of stargazers (Uranoscopus, perciformes) from the Mediterranean Sea basin: I. Divergence and taxonomic state of the Black Sea Stargazer

Based on museum collections, the variability of morphological characters of stargazers (Uranoscopus, Uranoscopidae) from different seas of the Mediterranean Sea basin have been studied. On the basis of the obtained results and data on the karyological divergence of the previously studied populations, stargazers of the Black Sea are regarded as an independent subspecies, Uranoscopus scaber anostomus, differing from the Mediterranean Sea populations in relatively long ventral fins, whose length usually exceeds half of the head length, the presence in most individuals of not less than 12 pyloric caeca, chromosome polymorphism with 2n = 28?C32, NF = 50, and the presence in the karyotype of a pair of marker small metacentric chromosomes. Morphological characters suitable for analysis of morphological divergence of populations of the Mediterranean region have been revealed.