New Deep-sea Leptognathiid Tanaids (Crustacea, Tanaidacea) from the North-east Atlantic

Three new genera ( Araphura, Leptognathioides and Stenotanais ) and six new species of tanaid crustaceans from below 1000 m depth in the north-east Atlantic are described. Two of the new species belong to the genus Leptognathiella Hansen, 1913, which is redescribed and removed from synonymy with Leptognathia Sars, 1882 ( sensu Lang 1968). These species are relatively common in the tanaid material examined and have a widespread distribution in the area under study, i.e. the Rockall Trough, Porcupine Seabight and Bay of Biscay. All six species are found at depths between 2070 and 2892 m. A further nine species previously belonging to the genus Leptognathia are removed to the new genera or to Leptognathiella. New records of Leptognathioides polita (Hansen, 1913) comb.n. and Leptognathiella abyssi (Hansen, 1913) have been obtained.     

Sexual reproduction in three hermaphroditic deep-sea Caryophyllia species (Anthozoa: Scleractinia) from the NE Atlantic Ocean

The reproductive biology and gametogenesis of three species of Caryophyllia were examined using histological techniques. Caryophyllia ambrosia, Alcock 1898, C. cornuformis, Pourtales 1868, and C. sequenzae, Duncan 1873, were collected from the Porcupine Seabight and Rockall Trough in the NE Atlantic Ocean. These three ahermatypic solitary corals inhabit different depth ranges: C. cornuformis – 435–2000 m, C. sequenzae – 960–1900 m, and C. ambrosia – 1100–3000 m. All three species are hermaphroditic. Hermaphroditism in these species was found to be cyclical, with only one sex of gametes viable in any individual at any point in time, although gametes of both sexes were found together within a single mesentery. Once the viable gametes are spawned, the next sex of gametes continues to grow until mature, and so gametogenesis is a continuous cycle. Oocytes and spermacysts in all species increased in density towards the actinopharynx. Maximum fecundity for C. sequenzae was 940 oocytes per polyp, and for C. ambrosia 2900 oocytes per polyp. Fecundity could not be established for C. cornuformis. In all three species, individuals were asynchronous within populations, and production of gametes was quasi-continuous throughout the year. All species are hypothesised to have lecithotrophic larvae owing to their large oocyte sizes (C. cornuformis max – 350 μm; C. sequenzae max – 430 μm; C. ambrosia max – 700 μm). Both the average oocyte size and fecundity increased in species going down the depth gradient of the NE Atlantic.     

Novel isotrichid ciliates endosymbiotic in Australian macropodid marsupials

Samples of foregut content were collected from 86 macropodid marsupials and examined for the presence of endosymbiotic ciliates. Four host species were examined: Macropus giganteus (eastern grey kangaroo), M. fuliginosus (western grey kangaroo), M. robustus (common wallaroo) and Thylogale billardierii (Tasmanian pademelon). Ciliate morphology was determined by microscopical examination of live and silver-impregnated specimens. Isotrichid ciliates were detected in 51 (59%) of the 86 animals examined. Five new species and one new genus are described. Three of the species belong to the genus Dasytricha Schuberg, 1888: D. dehorityi n. sp. from M. giganteus, D. dogieli n. sp. from M. robustus and D. mundayi n. sp. from T. billardierii. Bitricha n. g. is characterised by the possession of two fields of somatic ciliation, a transverse ventral and a longitudinal dorsal field. B. oblata n. sp. is described from M. giganteus and M. fuliginosus and B. tasmaniensis n. sp. is described from T. billardierii. The occurrence of isotrichid ciliates in both metatherian and eutherian mammals suggests that the family either evolved prior to the divergence of the mammalian lineages or switched hosts from one group to the other following host diversification.     

The reproductive biology of two deep-water,reef-building scleractinians from the NE Atlantic Ocean

The reproductive ecology of colonies of Lophelia pertusa (Linné 1758) and Madrepora oculata Linné (1758) from the Porcupine Seabight (Thérèse Mound and South Porcupine Seabight site) and the Darwin Mounds (NE Rockall Trough—L. pertusa only) was investigated using histological techniques. Samples of L. pertusa exhibited seasonal reproduction, whereas the evidence for M. oculata is equivocal but suggests multiple cohorts of gamete production. L. pertusa produces a single cohort of around 3,000 oocytes, whereas M. oculata produces two cohorts, with a total fecundity of around 60 oocytes. The maximum observed oocyte size in L. pertusa was 140 μm and in M. oculata was 405 μm. From these oocyte sizes and the timing of reproduction, a lecithotrophic larva is expected, though not observed. This seasonality of reproduction fits with the phytodetrital food fall occurring around July in the Seabight area. L. pertusa was found to be non-reproductive at the Darwin Mound site. Though unable to be specifically tested, this may suggest that the increased trawling activity in this area might be keeping colonies below sexually viable sizes, as seen in numerous shallow water situations. All areas in the NE Atlantic are coming under threat from increased fishing and commercial exploration practices. This study shows that these highly seasonal reproducers could be sensitive to these fishing operations and care must be taken so as not to repeat the destruction that has occurred on shallower reefs.     

Seamount egg‐laying grounds of the deep‐water skate Bathyraja richardsoni

Highly localized concentrations of elasmobranch egg capsules of the deep‐water skate Bathyraja richardsoni were discovered during the first remotely operated vehicle (ROV) survey of the Hebrides Terrace Seamount in the Rockall Trough, north‐east Atlantic Ocean. Conductivity–temperature–depth profiling indicated that the eggs were bathed in a specific environmental niche of well‐oxygenated waters between 4·20 and 4·55° C, and salinity 34·95–35·06, on a coarse to fine‐grained sandy seabed on the seamount's eastern flank, whereas a second type of egg capsule (possibly belonging to the skate Dipturus sp.) was recorded exclusively amongst the reef‐building stony coral Solenosmilia variabilis. The depths of both egg‐laying habitats (1489–1580 m) provide a de facto refuge from fisheries mortality for younger life stages of these skates.     

Abundance, distribution, reproduction and diet of notacanthid fishes from the north-east Atlantic

Notacanthid fishes were among the 10 most abundant species sampled in research surveys using fine meshed trawls fished to depths of 3000 m in the Rockall Trough and 4500 m in the Porcupine Seabight between 1975 and 1992. Two species, Noctacanthus bonapartei and Polyacanthonotus rissoanus , were dominant but their population structure and certain aspects of morphometric and reproductive biology differed between the two sampling areas. In general, sex ratios were skewed in favour of females, size increased with depth and male and immature individuals were restricted to shallower depth zones. Fecundity was highly correlated with total weight and showed a positive relationship with species' size. Ovaries contained two batches of eggs and the spawning season was protracted, occurring mostly over winter months. Dietary studies showed a dependence on benthic macro fauna though the two dominant species have different dentition and exploit different trophic niches. In the Rockall Trough, peak abundances for N. bonapartei and P. rissoanus occurred in the 750 m and 1250 m zones, respectively, lying within the depth range currently exploited by commercial deep-water trawls (600–1400 m). The probable impacts of commercial operations on notacanthid fishes are discussed.     

A new species ofMicrodajus (Crustacea: Tantulocarida) parasitic on a tanaid in the northeastern Atlantic,with observations onM. langi Greve

The tantulus larva ofMicrodajus langi is redescribed using Scanning Electron Microscopy. Thoracopods 2–5 have poorly developed but fully armed endites. Thoracopods 1–5 are biramous, with each ramus represented by a minute segment. A new species,M. pectinatus, is described from a tanaid host collected in the Rockall Trough, off the west coast of Scotland. A system of homologies for the portopodal segments of the thoracopods of the tantulus larva is proposed. Some aspects of the musculature of the adult male are described for the first time.     

Ultrastructure and Molecular Phylogeny of Mesodinium coatsi sp. nov., a Benthic Marine Ciliate

Mesodinium is a globally distributed ciliate genus forming frequent and recurrent blooms in diverse marine habitats. Here, we describe a new marine species, Mesodinium coatsi n. sp., originally isolated from interstitial water of surface sand samples collected at Mohang Beach, Korea. The species was maintained under a mixotrophic growth condition for longer than 1 yr by providing a cryptomonad, Chroomonas sp., as the sole prey. Cell morphology and subcellular structure were examined by light microscopy, scanning, and transmission electron microscopy, and molecular phylogeny was inferred from nuclear‐encoded 18S rDNA sequence data. Like other Mesodinium species, M. coatsi consisted of two hemispheres separated by two types of kinetids, and had tentacles located at the oral end of the cell. Several food vacuoles were observed in the cytoplasm, and partially digested prey cells sometimes existed in food vacuoles. Kinetids and the associated accessory structures were quite similar to those previously reported, but M. coatsi was differentiated from other marine Mesodinium species by ultrastructural characters of the dikinetids, polykinetids, and tentacles. We also provided a detailed illustration of infraciliature. Molecular phylogeny revealed that M. coatsi and Mesodinium chamaeleon were closely related to each other.     

Genome Size of Three <Emphasis Type="Italic">Miscanthus</Emphasis> Species

Environmental and economic factors have stimulated research in the area of bioenergy crops. While many plants have been identified as potential energy crops, one species in particular, Miscanthus x giganteus, appears to have the most promise. As researchers attempt to exploit and improve M. x giganteus, genome information is critical. In this study, the genome size of M. x giganteus and its two progenitor species were examined by flow cytometry and stomatal cell analyses. M. x giganteus was found to have genome size of 7.0 pg while Miscanthus sinensis and Miscanthus sacchariflorus were observed to have genome sizes of 5.5 and 4.5 pg respectively with stomatal size correlating with genome size. Upon computing the two tetraploid × diploid hybrids theoretical genome sizes, the data presented in this paper supports the hypothesis of the union of a 2x M. sacchariflorus and a 1x M. sinensis gamete for the formation of the allotriploid, M. x giganteus. Such genomic information provides basic knowledge that is important in M. x giganteus plant improvement.     

Effects of several establishment modes of Miscanthus × giganteus and Miscanthus sinensis on yields and yield trends

Miscanthus is a C4 perennial grass originating from East Asia, the yields of which progressively increase in the first years of growth. Several species for bioenergy have been studied since the mid‐1980s in Europe, in particular (Miscanthus × giganteus [M. × giganteus]), due to its high yields. M. × giganteus is mainly cultivated in France and established from rhizomes. Our study aimed to assess, in field conditions, alternative establishment methods combined with an alternative species, Miscanthus sinensis (M. sinensis). We set up a multi‐environment experimental network. On each trial, we tested two treatments with M. × giganteus, established from rhizomes (G_r‐sd) and from plantlets obtained from rhizomes (G_p‐sd), and two treatments with M. sinensis seedlings transplanted in single (S_p‐sd) and double density (S_p‐dd). ANOVA was performed to compare establishment and regrowth rates across treatments, as well as yields across treatments and site‐years. A logistic model was used to describe yield trends and to compare the maximum yield reached and the rate of yield increase of both species. Results showed that miscanthus establishment from plantlets resulted in higher establishment (between 87% and 92%) and regrowth (between 91% and 94%) rates compared to establishment from rhizomes. Treatments with M. × giganteus obtained higher average yields across site‐years than those with M. sinensis, but more variable yields across site‐years. We showed a strong species effect on yields, yield components (shoot weight, shoot density and shoot number per plant) and light interception (through leaf area index). Lastly, to use M. sinensis established from transplanted plantlets as an alternative to M. × giganteus, research would be required on the breeding of M. sinensis sterile seeds to avoid risks of invasiveness.     

Unexpected deep-sea fish species on the Porcupine Bank (NE Atlantic): Biogeographical implications

Four specimens corresponding to three rare deep-water fish species were caught on the Porcupine Bank (Northeast Atlantic) in September 2019. These catches include the new northernmost records of Azores rockling Gaidropsarus granti and deep-water dab Poecilopsetta beanii in the Atlantic Ocean and the second record of the latter species in its eastern zone. Three of the specimens were retained and their molecular identification also allowed the Cataetyx alleni DNA barcode to be obtained for the first time. The appearance of P. beanii, a West Atlantic species, in its eastern zone is discussed in relation to a possible phenomenon of transoceanic drift in the larval stage.     

New representatives of the genus Ancorabolina George, 2006 (Copepoda,Harpacticoida, Ancorabolidae) including remarks on ancorabolid phylogeny

Four new species of Ancorabolina George, 2006 (Copepoda: Harpacticoida: Ancorabolidae) are described: Ancorabolina belgicae sp. nov. (from the Porcupine Seabight, north‐east Atlantic Ocean), Ancorabolina anaximenesi sp. nov. and Ancorabolina galeata sp. nov. (both from Anaximenes Mountain, eastern Mediterranean Sea), and Ancorabolina divasecunda sp. nov. (from Cape and Guinea Basins, south‐east Atlantic Ocean). Furthermore, the generic diagnosis for Ancorabolina is provided and the position of the taxon within Ancorabolidae is discussed. The characters originally employed to allocate Ancorabolina to the subfamily Ancorabolinae Sars, 1909, are critically evaluated and two true autapomorphies for a monophyletic Ancorabolinae (including Ancorabolina) are recognized. Two autapomorphies supporting Ancorabolina are proposed: (1) cephalothorax posteriorly with pair of ventrolateral cuticular processes turned backwards and (2) loss of the third setal element subapically on the antennary endopod. The urgent need for a phylogenetic re‐evaluation of the paraphyletic subfamily Laophontodinae Lang, 1944 is stressed and evidenced by three characters widespread in this subfamily but also present in Ancorabolina. This may be an indication of a closer relationship of Ancorabolina with certain members of Laophontodinae. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 16–55.     

The Scyphomedusae of the Rockall Trough, northeastern Atlantic Ocean

An extensive series of samples between the surface and 2700m depth have been taken in the Rockall Trough between 1973 and1978. The coronate medusae, in decreasing order of abundanceoccurring in the Trough are: Periphylla periphylla, Atolla wyvillei,A. parva, A. vanhoeffeni and Nausitho? globifera. The last specieswas rare and no information on its biology was obtained. Theother species breed within the Trough, the three Atolla speciesthroughout the year. Few large mature Periphylla periphyllawere caught and its breeding season remains undefined. Theirmorphology and vertical and geographical distributions are brieflydiscussed. The semaeostomid medusae, Pelagia noctiluca, Aureliaaurita and Cyanea lamarckii also occurred, the latter two speciesconfined to the Rockall Bank.     

Deep-sea asellote isopods of the north-east Atlantic: the family Dendrotionidae and some new ectoparasitic copepods

A new species of Dendromunna and two new species of Dendrotion are described from abundant material collected in the Rockall Trough region of the north-east Atlantic. The taxonomy of the little known benthic deep-sea asellote isopod family Dendrotionidae is reviewed and keys provided for genera and species. Also diagnosed and described are two new species belonging to a new genus of siphonostomatoid copepod found as ectoparasites on the walking legs of the new Dendromunna. The new parasites belong in the Rhizorhina group of genera within the family Nicothoidae.     

A Resolution to the Blue Whiting (Micromesistius poutassou) Population Paradox?

We provide the strongest evidence to date supporting the existence of two independent blue whiting (Micromesistius poutassou (Risso, 1827)) populations in the North Atlantic. In spite of extensive data collected in conjunction with the fishery, the population structure of blue whiting is poorly understood. On one hand, genetic, morphometric, otolith and drift modelling studies point towards the existence of two populations, but, on the other hand, observations of adult distributions point towards a single population. A paradox therefore arises in attempting to reconcile these two sets of information. Here we analyse 1100 observations of blue whiting larvae from the Continuous Plankton Recorder (CPR) from 1948–2005 using modern statistical techniques. We show a clear spatial separation between a northern spawning area, in the Rockall Trough, and a southern one, off the Porcupine Seabight. We further show a difference in the timing of spawning between these sites of at least a month, and meaningful differences in interannual variability. The results therefore support the two-population hypothesis. Furthermore, we resolve the paradox by showing that the acoustic observations cited in support of the single-population model are not capable of resolving both populations, as they occur too late in the year and do not extend sufficiently far south to cover the southern population: the confusion is the result of a simple observational artefact. We conclude that blue whiting in the North Atlantic comprises two populations.     

Morphology and sedimentology of (clustered) cold-water coral mounds at the south Rockall Trough margins,NE Atlantic Ocean

Cold-water coral mounds on both margins of the Rockall Trough (NE Atlantic Ocean) have a strongly different morphology. Single, isolated mounds occur on the SE margin and are mainly found on the upper slope between 900 and 650 m water depth, while large mound clusters are found on the SW margin in water depths between 600 and 1,000 m, in a narrow zone almost parallel to the slope. Sedimentation rates on the mounds are higher than on the surrounding seabed as a result of baffling of biogenic carbonate debris and siliciclastic particles by the coral framework covering the mounds. This is confirmed by ²¹⁰Pb measurements. The individual coral growth rate can be three times higher then the vertical growth rate of the coral cover (±10 mm year⁻¹) which in turn is more than an order of magnitude higher then the present-day overall mound growth rate (±0.25 mm year⁻¹). The presence of extensive hardgrounds and firmgrounds and the three-dimensional coral framework are considered to be responsible for the stability of the relatively steep slopes of the mounds. High current velocities in the intramound areas result in local non-sedimentation and erosion, as is shown by the presence of IRD (ice-rafted debris) lag deposits on the seabed and moats around some of the mounds. The morphology and sedimentology of cold-water coral-covered (mainly Lophelia pertusa and Madrepora oculata) mounds on the southern Rockall Trough margins (NE Atlantic Ocean) is discussed and a model describing the development of these mounds is presented.     

New click beetles (Coleoptera: Elateridae) from the cretaceous of Russia and Kazakhstan

A new tribe, two new genera, and seven new species of click beetles are described: Pollostelaterini, trib. nov., Pollostelater baissensis, gen. et sp. nov. from the Lower Cretaceous of Transbaikalia (Baisa locality), five new species in the genus Cryptocoelus Dolin et Nel C. sinitshenkovae, sp. nov. (Romanovka locality), C. shcherbakovi, sp. nov., C. baissensis, sp. nov., C. lukashevichae, sp. nov., C. dolini, sp. nov. (all from Baisa locality), and Turonelater giganteus, gen. et sp. nov. from the Turonian of Southern Kazakhstan (Kzyl-Dzhar locality).