Pleistocene fish otoliths from the Mediterranean Basin: a synthesis

An overview of upper pPliocene and pleistocene otolith assemblages is compiled on the basis of both literature data and newly collected material from several sections located mainly in southern Italy. One hundred and five taxa are listed. Additional comments are provided for taxa subject to discussion. The composition and affinities of the Mediterranean Pleistocene otolith associations (consisting mainly of deep sea fishes) is checked against the available data for Pre-Messinian, Pliocene, and Recent Mediterranean fishes. This analysis is based on the recorded nominal species, but some taxa that could be identified at the generic level only are also included when they are relevant from a biogeographic point of view. Some new data on Piacenzian (middle Pliocene) and Gelasian (upper Pliocene) otoliths are also provided because this time interval still constitutes a major gap in the knowledge of the stratigraphic range of Plio-Pleistocene fish taxa. The Pleistocene deepwater fish fauna of the Mediterranean shows a markedly more oceanic character than the present-day one, a tendency that was all ready observed from early Oligocene till Pliocene times. Starting from the late Piacenzian, an increasing number of Atlantic taxa progressively invaded the Mediterranean including several subpolar and temperate forms. This invasion became stronger in the Gelasian. From this period up to the middle and late Pleistocene, the Mediterranean deepwater fish fauna (mesopelagic and benthopelagic) is enriched by taxa which today are typical for the north Atlantic cold deep water. This faunal shift seems to be correlated with the evolution of the Plio-Pleistocene Mediterranean paleoceanographic setting as well as with the global climatic deterioration.     

Peracarida populations of hard substrate assemblages in ports of the NW Aegean Sea (eastern Mediterranean)

This study deals with the structure of Peracarida populations in four ports in the NW Aegean Sea, Greece, and with the degree this structure is influenced by the particular biotic and abiotic conditions that prevail in the ports. Quantitative samples were taken during summer and winter in two successive years from artificial hard substrates and were analysed using common biocoenotic methods. The examination of approximately 81,250 specimens revealed the presence of 24 Peracarida species, the most dominant of which were Corophium acutum, Leptochelia savignyi and Elasmopus rapax. All species are very common and have been reported from many sites and assemblages in the N Aegean Sea. The ratios of certain Peracarida genera are discussed as possible indicators of environmental health that may be used in long-term biomonitoring programmes on the impact of pollution in harbours.Communicated by H.-D. Franke     

Lessepsian migrant Fistularia commersonii from the Rhodes marine area

The bluespotted cornetfish Fistularia commersonii which originates from the Red Sea, appeared in the marine area of Rhodes Island (south-east Aegean Sea). This is a new record of the species based on 37 specimens caught during summer-winter 2001. The species appears to be spreading rapidly west and easily becoming established in Mediterranean coastal habitats.     

Extant silicoflagellates from the Northeast Aegean (eastern Mediterranean Sea): Morphologies and double skeletons

Silicoflagellate abundance, vertical distribution and morphology were studied during spring (March 2014) at three sampling stations located in the Northeast Aegean Sea adjacent to the Dardanelles Strait and characterized by a variable influx of cold, low-salinity Black Sea water. The silicoflagellate assemblage was dominated by Dictyocha stapedia and Stephanocha speculum with minor contribution of D. aculeata and Octactis pulchra. While specimens of D. stapedia were represented by the typical morphologies described in other areas of the Mediterranean Sea, populations of S. speculum displayed peculiar characters: they were large, predominantly 7-sided, with a small apical ring as well as apical ring spines, concave basal ring sides and non-rotated apical structure. Some of these features have been described for S. speculum at high latitudes, but the combined characters make these specimens slightly different from the high latitude populations. Similar morphologies have been observed in the western Black Sea, thus we can infer that the peculiar specimens detected in the Northeast Aegean are associated with the influx of Black Sea water masses.     

Stephanorhinus hundsheimensis (Mammalia,Rhinocerotidae) from the late early Pleistocene deposits of the Denizli Basin (Anatolia,Turkey)

Pleistocene rhinoceroses are poorly documented in Turkey where they have been reported only from the late early Pleistocene (1.3–1.1 Ma) travertine deposits of the Denizli Basin. In this work, new rhinoceros remains collected from this basin are assigned to a relatively large-sized Stephanorhinus hundsheimensis on the basis of their morphology and morphometry. The first Turkish record of this species is approximately coeval with the first appearance of S. hundsheimensis in Europe, chronologically referred to the late early Pleistocene, ca. 1.2 Ma. During that time, S. etruscus still survived in Iberian Peninsula, central Italy and Dacian Basin. The presence of two successive evolutionary morphs for S. hundsheimensis during the Pleistocene is not confirmed.     

The diet of native and invasive fish species along the eastern Mediterranean coast (Osteichthyes)

The opening of the Suez Canal in 1869 enabled the invasion of more than 100 alien fish species into the Mediterranean. The aim of the present study was to compare the diet of native and alien fish species and to identify possibly shared food resources. We examined the diet composition of 13 of the most abundant fish species (6 alien, 7 native) on shallow soft bottom off southern Israel. All 13 species are omnivorous/carnivorous. The native fish exhibited a wider diversity of food types than the aliens. Alien fish prey upon and are preyed by native species as well as by other alien fish. A high level of diet overlap was found among some species, the aliens Saurida lessepsianus and Scomberomorus commerson overlapped with the native Synodus saurus; and the alien Nemipterus randalli with the native species Pagrus caeruleostictus, Lithognathus mormyrus and Pagellus erythrinus. The identified diet overlap is discussed, and the possibility of competitive interactions between these species is considered.     

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.     

Seasonal variations of microphytoplankton assemblages and environmental variables in the coastal zone of Bozcaada Island in the Aegean Sea (NE Mediterranean Sea)

Seasonal changes in the microphytoplankton assemblages were examined in the coastal zone of Bozcaada Island with regard to some major physical and chemical variables. Samples were collected from May 2000 to December 2001 at four stations. A total of 108 dinoflagellates, 102 diatoms, 1 chrysophycean, 3 dictyochophycean, and 1 prasinophycean species were identified and quantified during the study period. Diatoms and dinoflagellates were the most important in terms of species number and abundance. The maximum values of total microphytoplankton were observed at 0.5 m depth (46.2 × 10³ cells l⁻¹ at st. 3) in May as this was the month when the diatom Pseudo-nitzschia pungens bloomed. Chlorophyll (chl) a concentration ranged between 0.08 (August) and 0.78 μg l⁻¹ (February). May was another important month in which chlorophyll a increased (0.41–0.47 μg l⁻¹). Species diversity values (H′_log2) ranged from 1.66 bits (June, 20 m) to 4.11 bits (November, 0.5 m). The increase was attributed to a more balanced distribution of abundance among species. The amounts of nitrate + nitrite (0.6−3.7 μg-at N l⁻¹), phosphate (0.2−0.6 μg-at P l⁻¹) and silicate (0.7−2.5 μg-at Si l⁻¹) were recorded on each sampling occasion. Nutrient concentrations and chl a values of the research area were found to be poorer than those of the many other coastal areas in the northeastern Mediterranean. The mean atomic ratio of nitrogen to phosphorus varied from 1.3 (June) to 12.9 (February). This ratio was lower than the Redfield ratio of 16 for ocean phytoplankton, and phytoplankton was potentially limited by nitrogen for most of the months. The result of this study confirms and emphasizes the oligotrophic nature of the eastern Mediterranean.     

Paleocene-Early Eocene ostracodes from the Southern Galala Plateau (Eastern Desert, Egypt): Taxonomy, impact of paleobathymetric changes

Ostracode faunas obtained from nine sections spanning the Paleocene-Early Eocene interval from a platform-basin transect in the Southern Galala Plateau area (Eastern Desert, Egypt) have been investigated. The study focuses on taxonomy and biostratigraphy of the ostracode assemblages across the P/E boundary, with supporting comments on paleoecology and paleobiogeography. The studied nine sections yielded 60 taxa belonging to 39 genera. Five species are new. The P/E transition is characterized by the appearance of new taxa rather than extinctions. During the Early and early Late Paleocene, the ostracode assemblages throughout the study area are largely similar, being dominated by middle-outer neritic taxa. In the late Late Paleocene and Early Eocene, changes in the paleobathymetry from deeper marine environments in the distal area in the south to shallower marine environments in the proximal area in the north become pronounced. Many of the recorded taxa have a wide geographic distribution throughout the Middle East and North Africa. Similarities with basins of West Africa are also found, reflecting faunal exchanges between this area and southern Tethys during the Paleocene and Early Eocene.     

Cryptic speciation in the Merodon luteomaculatus complex (Diptera: Syrphidae) from the eastern Mediterranean

The Merodon aureus group is characterized by high endemism and the presence of morphologically cryptic species. Within one of its subgroups, M. bessarabicus, seven species and four more species complexes have been described to date. One of these complexes, the M. luteomaculatus, comprises new taxa that are the subject of the present study. Its members have allopatric ranges restricted to the Balkan Peninsula and Aegean islands. This complex exhibits morphological variability that could not be characterized using a traditional morphological approach. Thus, we used integrative taxonomy with independent character sets (molecular, geometric morphometric, distributional) to delimit species boundaries. Data on three molecular markers (COI, 28S rRNA, and ISSR) and geometric morphometry of the wing and male genitalia, together with distributional data, enabled recognition of six cryptic species within the complex: M. andriotes sp. n., M. euri sp. n., M. erymanthius sp. n., M. luteomaculatus sp. n., M. naxius sp. n., and M. peloponnesius sp. n. We discuss the possible influence of Aegean paleogeographical history on the speciation of this complex.     

Fossil fish otoliths from the Chibanian Miyata Formation,Kanagawa Prefecture,Japan, with comments on the paleoenvironment

The Paleo-Tokyo Bay (Kanto Plateau) that persisted during the transgression periods in the Middle-Late Pleistocene is known for its rich marine fauna that accommodated both the warm and cold water taxa brought by the Kuroshio and Oyashio Currents, respectively. However, little is known on the paleoichthyofauna in this area and the processes shaping the marine ichthyofauna of modern southern Kanto. We used fossil fish otoliths and teeth discovered in the Sha’ana Tuffaceous Sand Member belonging to the Chibanian Miyata Formation, exposed at Sha’ana-dai, Miura City, Kanagawa Prefecture, Japan, to reconstruct the paleoichthyofauna and its associated paleoenvironment and explore the content of fish assemblages during this period. The Sha’ana Tuffaceous Sand Member was composed of upper sandy mud and lower muddy sand horizons at the exposure. A total of 1,675 fish remains were collected from this site, of which 1,389 were assigned to 62 distinct taxa (20 orders, 31 families). The taxonomic composition revealed taxa from various environments, including shallow continental shelf, epi- to meso-pelagic settings, and the majority were from a generally temperate climatic zone. Paleoenvironmental analyses suggested that the fish assemblages were from the continental shelf (approximate depth of 100–200 m) in a temperate sea where both warm Kuroshio and cold Oyashio Currents had an influence on the biota. The analysis also showed that two boreal fishes, namely Clupea pallasii and Theragra chalcogramma, once had a wider distribution that extended to the southwestern areas of the Paleo-Tokyo Bay. This study provides a more complete view of the related paleobiogeography of marine fishes during the Chibanian and is essential for reconstructing the evolutionary processes of the rich ichthyofauna in the southern Kanto.     

Genetic cohesion of Eresus walckenaeri (Araneae, Eresidae) in the eastern Mediterranean

The eresid spider genus Eresus is morphologically and ecologically conservative. At least three species occur in Europe. However, deep genetic divergence among geographical samples within two species, E. cinnaberinus and E. sandaliatus , may suggest more cryptic species. In the present study we investigate the genetic cohesion of the third species, Eresus walckenaeri , throughout its eastern Mediterranean distribution range, relative to the E. cinnaberinus–E. sandaliatus species complex. Eresus walckenaeri specimens were monophyletic. Genetic discreteness of E. walckenaeri in a region of sympatry with its sister species in Greece provides evidence for species integrity of E. walckenaeri within the European Eresus species complex. Eresus walckenaeri exhibited high concordance between geographical location and mtDNA genealogy. Two major phylogeographical clades were found in the Greek–Turkish and Syrian–Israel parts of the investigated area, respectively (∼6.5% sequence divergence). Concordance between geography and genetic divergence was further observed between Aegean island samples and their corresponding Greek and Turkish mainland samples, suggesting regional subdivision with gradual but potentially high dispersal propensity. Monophyly and limited regional distribution indicate Mediterranean endemic origin.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 1–9.     

Fish otoliths from the Priabonian (Late Eocene) of North Italy and South-East France - Their paleobiogeographical significance

The study of the Late Eocene (Priabonian) otolith associations from Possagno, North-East Italy, and from the Synclinal d’Allons in Haute Provence, South-East France, allows for the reconstruction of a teleost fauna of 55 taxa, which is the most diversified assemblage presently known from the Upper Eocene Paleo-Mediterranean basin. Thirty-six taxa are identified at the species level, and five of those are new: “genus Alepocephalidarum” astrictus, “genus Lophiiformorum” canovae, “genus Agonidarum” sudans, “genus Uranoscopidarum” cochlearis and Aseraggodes laganum. In the Synclinal d’Allons, the otolith associations reflect a tropical to subtropical neritic environment with a few mesopelagic fishes. At Possagno, the associations indicate an environment that changed from one that was deep and exposed to the pelagic realm and then evolved to a more shallow sea with a well-diversified benthic life and less mesopelagic fishes. A paleobiogeographical analysis of all known data on Priabonian otoliths, worldwide, shows clearly a western Atlantic (Louisiana) and an eastern Atlantic-Paleomediterranean association. In the eastern Atlantic-Paleomediterranean association, the Aquitaine association not only differs from the Possagno-Allons association in function of its more distant geographical position, but also by its stronger oceanic character in the southern part of the basin, and by the occurrence in the north, of a very shallow water facies (Saint-Estephe Formation) that contains some taxa which are known nowhere else in the Priabonian. The Ukraine fauna is characterized by a high number of species, which have an Oligocene record in other European sites. The northern geographic location of Ukraine, combined with the good connections to both the North Sea Basin and the Turgai street can provide the explanation. Many Oligocene species (or their close relatives) probably already existed at Eocene times in more northern regions, but could penetrate only in more southern European seas since the strong cooling at the beginning of the Oligocene.     

The littoral fish community of the Lebanese rocky coast (eastern Mediterranean Sea) with emphasis on Red Sea immigrants

The organisation of the coastal rocky fish community of Lebanon was investigated for the first time, using visual censuses. A total of 62 fish species were recorded between the surface and 32 m depth, 8 species being Red Sea migrants. Species richness and fish abundance were positively correlated first with substrate complexity and second with depth. The trophic structure of the community was dominated by diurnal zooplanktivores (Chromis chromis, Oblada melanura and Spicara smaris) and mesocarnivores 1 (Coris julis and Thalassoma pavo), and did not vary significantly with depth. The Lessepsian migrants represented 13% of the species richness and 19% of the total abundance of individuals. They dominated among herbivores, nocturnal zooplanktivores and macrocarnivores. The Lessepsian Siganus luridus and S. rivulatus (Siganidae), Pempheris vanicolensis (Pempheridae) and Sargocentron rubrum (Holocentridae) were now among the most common fish species on the Lebanese rocky coast. Lessepsian fish species displayed either similar ecological niches in the Red Sea and in the Levantine basin (P. vanicolensis, S. rubrum) or an enlargement of their depth distribution towards deeper waters in their new environment (S. luridus, S. rivulatus). This study will serve as a baseline for future studies as eastern Mediterranean communities are subjected to a steady increase in Red Sea migrant species.     

Coralligène formations in the eastern Mediterranean Sea: Morphology, distribution, mapping and relation to fisheries in the southern Aegean Sea (Greece) based on high-resolution acoustics

Coralline algae are one of the most important constructors of biogenic habitats. In the Mediterranean Sea, the dominant coralline algae species form crusts comprising formations known as coralligène, considered as very important fishing grounds by fishermen. Due to the destructive effect of fishing gear activities over coralligène, these formations were recently protected from the use of active benthic gears by the EU 1967/2006 Mediterranean fisheries management Regulation. However, the lack of maps and information on their distribution makes the effective application of these measures impossible. The present publication contributes to the mapping of coralligène in the southern Aegean Sea (eastern Mediterranean), and to the study of coralline algae formation morphology, distribution, development conditions and relation to fisheries using a combination of single-beam echo sounder, sidescan sonar, sub-bottom profiler recordings and biological and sedimentological ground-truthing techniques. The coralligène formations were recognized as two distinct acoustic signatures of localized backscatter facies distinguishable from other hard substrate reflectors at depths ranging from 55.9 to 114.0 m, but mainly between 70 and 90 m. Two types of formations were identified: minute reefs 0.5-2.5 m in height and superficial layer formations no more than 0.2 m thick over the substrate. The seismic profiles revealed a cavernous internal structure of the minute reefs and recorded their development on both hard and soft substrates. The distribution of formations was contagious, creating aggregations. The finding of superficial layer formations and coralline shreds around minute coralligène reefs indicated that the former could be an intermediate development type between isolated small coralline pebbles, rhodoliths, and minute reefs. Regarding the development conditions, sidescan sonar imagery indicated that the optimal conditions for the establishment and development of coralligène formations are medium intensity currents. Concerning human activity over coralligène, trawl traces were recorded near but not over minute reefs and both near and crossing superficial layer type aggregations, while a submarine cable was also recorded among minute reefs. The mapping of coralligène aggregation areas is essential for the application of the EU Regulation and the protection of this important marine habitat.     

Fish otoliths from the Pliocene Heraklion Basin (Crete Island,Eastern Mediterranean)

The Pliocene Eastern Mediterranean fish record is revealed through the study of a 60-m thick stratigraphic sequence near the village Voutes (Heraklion, Crete). Forty-two species belonging to twenty families are identified. Calcareous nannoplankton biostratigraphy places the studied sequence within the biozone MNN16a (latest Zanclean). The stratigraphic distribution of 31 species is modified. Among these, 12 species are reported for the first time in the Eastern Mediterranean Zanclean, while 19 species are first reported outside the Ionian Sea. The Voutes fish fauna presents a diversified benthic and benthopelagic assemblage filling a significant gap in the fossil record.     

New materials of Cisuralian (early Permian) radiolarians from western Cambodia: Paleobiogeographic implications in the Paleotethys

Radiolarians, including the new species Entactinia pailinensis Ito n. sp., were obtained from the Pailin area, western Cambodia. The radiolarians indicated an age around the Asselian–Sakmarian of the Cisuralian (early Permian). The new species is characterized by an evenly-sized-porous exosphere composed of a polygonal outer porous plate and circular inner porous plate with some radial outer spines. A previous study concluded that Entactinia Foreman rapidly expanded in the early–middle Cisuralian. Our discovery of this new species adds further occurrence data of Entactinia in the early–middle Cisuralian. In addition, another previous study highlighted the uneven distribution of Pseudotormentus De Wever and Caridroit compared with the wider distribution of Quadriremis Nazarov and Ormiston through the Permian, in particular the Guadalupian (middle Permian). Our results combined with those of previous studies indicate that the uneven distribution might extend back to the Sakmarian of the Cisuralian at least.     

Diversity of juvenile fish assemblages in the pelagic waters of Lebanon (eastern Mediterranean)

Oxygen consumption rates of nauplii of the brine shrimp Artemia franciscana Kellogg 1906 were determined over a range of salinities from 10 to 110 ppm, in temperatures from 0 to 30°C, using a multi-factorial design. The oxygen micro-sensors employed have a fast response time and are capable of accurately measuring oxygen concentrations at temperatures well below 0°C. Oxygen uptake rate ranged from 0.03 to 0.66 μmol O₂ mg⁻¹ h⁻¹ and was sensitive to changes in both salinity and temperature. Temperature was the dominant factor affecting oxygen consumption rates, which showed a significant increase with increasing temperature. A slight decrease was measured in oxygen consumption with increasing salinity related to differential solubility of oxygen in waters of different salinities. Thermal sensitivity of oxygen consumption determined from calculations of Q ₁₀, indicated physiological adaptation of Artemia nauplii to the ranges of temperatures tested. Handling editor: A. van Kerchove     

New material of Diacodexis (Mammalia,Artiodactyla) from the early Eocene of Southern Europe

Diacodexeidae are the first representatives of Artiodactyla in the fossil record. Their first occurrence is at the very base of the Ypresian (earliest Eocene, 56.0 Ma) with Diacodexis, a genus well diversified during the early Eocene in Europe, especially during the MP7–MP8 + 9 interval. However, most of European species are documented by scarce material, retrieved from single localities. In this work, we describe new Diacodexis material from ～MP7 and ～MP8 + 9 localities of Southern Europe, including material of D. antunesi from Silveirinha, considered as the most primitive European Diacodexis species, and material from three localities from Southern France (Fordones, Palette, and La Borie). The new material documents Diacodexis premolar morphology and deciduous dentition which bear potentially important phylogenetic information, as well as astragali, including a specimen from Silveirinha that constitutes the earliest occurrence of an astragalus of the genus Diacodexis in the European fossil record. Investigation of the enamel microstructure reveals that early European species had a simple enamel pattern with one-layered Schmelzmuster composed of ‘basic’ radial enamel only, instead of the two-layered Schmelzmuster (thin radial enamel + thick layer of Hunter-Schreger bands) observed on North American species and so far considered to represent the primitive condition within Artiodactyla. In accordance with previous studies, our observations highlight that Diacodexis gigasei from Belgium is morphologically closer to the North American species D. ilicis than to D. antunesi from Portugal. The latter species, together with D. aff. antunesi from Fordones, appears to be morphologically closer to the Asiatic taxa D. indicus and D. pakistanensis. Finally, we found numerous similarities between D. cf. gigasei from Palette and D. gigasei, a result that challenges the intra-European provincialism that characterizes the earliest Ypresian. Diacodexis gigasei could be one of the rare species shared by the northwestern and southwestern European bioprovinces.