Highlights d Unprecedented levels of abyssal ophiuroid biodiversity in the Eastern Pacific Ocean d The new lineages occur in polymetallic nodule mining license areas d Three of the new lineages are greater than 70 million years in age

Abstract. The largest and commercially appealing mineral deposits can be found in the abyssal sea floor of the Clarion-Clipperton Zone (CCZ), a polymetallic nodule province, in the NE Pacific Ocean, where experimental mining is due to take place. In anticipation of deep-sea mining impacts, it has become essential to rapidly and accurately assess biodiversity. For this reason, ophiuroid material collected during eight scientific cruises from five exploration licence areas within CCZ, one area being protected from mining (APEI3, Area of Particular Environmental Interest) in the periphery of CCZ and the DISturbance and re-COLonisation (DISCOL) Experimental Area (DEA), in the SE Pacific Ocean, was examined. Specimens were genetically analysed using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI). Maximum-likelihood and neighbour-joining trees were constructed, while four tree-based and distance-based methods of species delineation (automatic barcode gap discovery, ABGD; barcode index numbers, BINs; general mixed Yule–coalescent, GMYC; multi-rate Poisson tree process, mPTP) were employed to propose secondary species hypotheses (SSHs) within the ophiuroids collected. The species delimitation analyses' concordant results revealed the presence of 43 deep-sea brittle star SSHs, revealing an unexpectedly high diversity and showing that the most conspicuous invertebrates in abyssal plains have been so far considerably underestimated. The number of SSHs found in each area varied from five (IFREMER area) to 24 (BGR (Federal Institute for Geosciences and Natural Resources, Germany) area) while 13 SSHs were represented by singletons. None of the SSHs were found to be present in all seven areas while the majority of species (44.2 %) had a single-area presence (19 SSHs). The most common species were Ophioleucidae sp. (Species 29), Amphioplus daleus (Species 2) and Ophiosphalma glabrum (Species 3), present in all areas except APEI3. The biodiversity patterns could be mainly attributed to particulate organic carbon (POC) fluxes that could explain the highest species numbers found in BGR (German contractor area) and UKSRL (UK Seabed Resources Ltd, UK contractor area) areas. The five exploration contract areas belong to a mesotrophic province, while conversely the APEI3 is located in an oligotrophic province, which could explain the lowest diversity as well as very low similarity with the other six study areas. Based on these results the representativeness and the appropriateness of APEI3 to meet its purpose of preserving the biodiversity of the CCZ fauna are questioned. Finally, this study provides the foundation for biogeographic and functional analyses that will provide insight into the drivers of species diversity and its role in ecosystem function.

<p><strong>Abstract.</strong> The largest and commercially appealing mineral deposits can be found in the abyssal seafloor of the Clarion-Clipperton Zone (CCZ), a polymetallic nodule province, in the NE Pacific Ocean, where experimental mining is due to take place. In anticipation of deep-sea mining impacts, it has become essential to rapidly and accurately assess biodiversity. For this reason, ophiuroid material collected during seven scientific cruises from five exploration license areas within CCZ, one area protected from mining (APEI3, Area of Particular Environmental Interest) in the periphery of CCZ and the DIS-turbance and re-COLonisation (DISCOL) Experimental Area (DEA), in the SE Pacific Ocean, was examined. Specimens were genetically analysed using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI). Maximum Likelihood and Neighbour Joining trees were constructed, while four tree-based and distance-based methods of species delineation (ABGD, BINs, GMYC, mPTP) were employed to propose Secondary Species Hypotheses (SSHs) within the ophiuroids collected. The species delimitations analyses concordant results revealed the presence of 43 deep-sea brittle stars SSHs, revealing an unexpectedly high diversity and showing that the most conspicuous invertebrates in abyssal plains have been so far considerably under-estimated. The number of SSHs found in each area varied from 5 (IFREMER area) to 24 (BGR area), while 13 SSHs were represented by singletons. None of the SSHs was found to be present in all 7 areas, while the majority of species (44.2 %) had a single-area presence (19 SSHs). The most common species were Ophioleucidae sp. (Species 29), <i>Amphioplus daleus</i> (Species 2) and <i>Ophiosphalma glabrum</i> (Species 3), present in all areas except APEI3. The biodiversity patterns could be mainly attributed to POC fluxes that could explain the highest species numbers found in BGR (German contractor area) and UKSRL (UK contractor area) areas. The five exploration contract areas belong to a mesotrophic province, while in contrary the APEI3 is located in an oligotrophic province which could explain the lowest diversity as well as very low similarity with the other six study areas. Based on these results the representativeness and the appropriateness of APEI3 to meet its purpose of preserving the biodiversity of the CCZ fauna are questioned. Finally, this study provides the foundation for biogeographic and functional analyses that will provide insight into the drivers of species diversity and its role in ecosystem function.</p>

Atyaephyra de Brito Capello, 1867 was described from the Mediterranean region almost 200 years ago. Since then, the genus has been recorded from various freshwater habitats in Europe, North Africa and the Middle East. Despite its long history, the taxonomic status of Atyaephyra species remains confusing and uncertain. Consequently numerous specimens from the known range of Atyaephyra were analysed using morphological characters and mitochondrial COI sequences in an attempt to clarify the taxonomy of this genus. The present study recognises seven Atyaephyra species, more than twice as many as previously recorded (three), four of which are considered as new. The new species are described, additional information to the original descriptions are provided for the remaining three taxa, while neotypes of Atyaephyra desmarestii Millet, 1831 and Atyaephyra stankoi Karaman, 1972 are designated to stabilize their taxonomy. Non-overlapping distinguishing morphological characters are used to discriminate the examined material into five species, e.g., Atyaephyra desmarestii, Atyaephyra stankoi, Atyaephyra orientalis Bouvier, 1913, Atyaephyra thyamisensis sp. n., Atyaephyra strymonensis sp. n. In addition, the genetic analysis supports the existence of multiple phylogenetic clades in the broader Mediterranean area and distinguishes two new cryptic species, namely Atyaephyra tuerkayi sp. n. and Atyaephyra acheronensis sp. n. The geographic distribution of these species is confirmed and their phylogenetic relationships are described.

The organismic assemblage associated with Caretta caretta was studied in 37 loggerhead turtles, washed ashore dead at various localities in the northern Aegean Sea. A total number of 63 macrobenthic species and 17 species of macroalgae were identi¢ed. From these species, 41 and 13 respectively are reported for the ¢rst time as epibionts of this turtle. Analysis of the epibiont species distribution on six loggerhead turtles gave some evidence regarding the settlement preferences of certain epibiont species. From a biogeographical point of view, 61.3% of the epibiont species were cosmopolitan, 30.7% had an AtlantoMediterranean distribution, while 8% were Mediterranean endemics.

Examination of sampled material and review of the relevant literature revealed the presence of 299 benthic and 46 pelagic amphipod species from the Aegean Sea. Two of the species identified, Caprella hirsuta Mayer, 1890 and Apohyale crassipes (Heller, 1866), are recorded for the first time in the Aegean Sea and the Levantine Basin respectively. A checklist of the Mediterranean amphipods is given, as well as their distribution in the Mediterranean territorial areas and the Black Sea. The faunal comparison of the Mediterranean areas showed that the number of species decreases from west to east. In terms of zoogeographical categories the Atlanto-Mediterranean species dominate in all Mediterranean areas followed by the endemic species concerning the benthic amphipods while in pelagic amphipods cosmopolitan species dominate and are then followed by Atlanto-Mediterranean. Three species, Bemlos leptocheirus (Walker, 1909) and Linguimarea caesaris Krapp-Schickel, 2003, Photis lamellifera Schellenberg, 1928, are lessepsian migrants and are reported in the Levantine and Central Mediterranean Seas.

In order to elucidate the distinction of Atyaephyra desmarestii subspecies (A. d. desmarestii, A. d. orientalis, A. d. stankoi and A. d. mesopotamica ) and investigate their geographical distribution in Greece, the main morphological features and somatometric ratios were studied in numerous specimens collected from a dense station network of Greek fresh waters. Specimens from Belgium, Portugal, Albania and Turkey were also examined. Atyaephyra desmarestii was found in western and northern Greece while it was absent in eastern Greece , the Aegean and the Ionian islands. The comparison of the obtained data with those of the literature revealed a clearly overlapping variability of the main key morphological features among the four subspecies. The results of this study indicate that the current A. desmarestii subspecies are not valid on the basis of the used key features. There is only one very variable species with many ecophenotypes.

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