Draconematidae (Nematoda) from cold-water corals in the Porcupine Seabight: The genus Cygnonema Allen & Noffsinger, 1978

Two new and closely related species of the genus Cygnonema Allen & Noffsinger, 1978 are described from a cold-water coral degradation zone in the Porcupine Seabight (NE Atlantic). Both species differ from C. steineri Allen & Noffsinger, 1978 by more pronounced pharyngeal and posterior swellings, a smaller body, a shorter pharynx in relation to body length, a higher number of CAT, and by the absence of a dorsal tooth. Cygnonema verum sp. n. differs from C. belgicae sp. n. by its greater body length, the relatively larger head capsule, a higher number of CAT, a more anteriorly positioned anteriormost laterodorsal CAT, a higher number of PAT, by the external labial sensilla being setiform, a higher number of subcephalic setae, and by a more anterior position of the amphidial fovea on the head capsule. Males of C. verum sp. n. are easily recognised by the presence of two large subventral, precloacal corniform setae. They also differ from males of C. belgicae sp. n. in the smaller amount of cytoplasm in the sperm cells, a knob-like capitulum, and a relatively shorter tail tip. The diagnosis of Cygnonema is emended, a dichotomic identification key to the three species is provided, and their biogeography is discussed.     

Recent benthic foraminiferal assemblages from cold-water coral mounds in the Porcupine Seabight

Cold-water coral ecosystems are characterised by a high diversity and population density. Living and dead foraminiferal assemblages from 20 surface sediment samples from Galway and Propeller Mounds were analysed to describe the distribution patterns of benthic foraminifera on coral mounds in relation to different sedimentary facies. Hard substrates were examined to assess the foraminiferal microhabitats and diversities in the coral framework. We recognised 131 different species, of which 27 prefer an attached lifestyle. Epibenthic species are the main constituents of the living and dead foraminiferal assemblages. The frequent species Discanomalina coronata was associated with coral rubble, Cibicides refulgens showed preference to the off-mound sand veneer, and Uvigerina mediterranea displayed abundance maxima in the main depositional area on the southern flank of Galway Mound, and in the muds around Propeller Mound. The distribution of these species is rather governed by their specific ecological demands and microhabitat availability than by the sedimentary facies. Benthic foraminiferal assemblages from coral mounds fit well into basin-wide-scale distribution patterns of species along the western European continental margin. The diversity of the foraminiferal faunas is not higher on the carbonate mounds as in their vicinity. The living assemblages show a broad mid-slope diversity maximum between 500 and 1,300 m water depth, which is the depth interval of coral mound formation at the Celtic and Amorican Margin. The foraminiferal diversity maximum is about 700 m shallower than comparable maxima of nematodes and bivalves. This suggests that different processes are driving the foraminiferal and metazoan diversity patterns.     

New species of Glochinema and Metaglochinema (Nematoda, Epsilonematidae) from New Caledonia

Glochinema phaleratum sp. n. and Metaglochinema strigosum sp. n. (Glochinematinae, Epsilonematidae) arc described from supralittoral marine sediments in New Caledonia.     

Diversity and community structure of harpacticoid copepods associated with cold-water coral substrates in the Porcupine Seabight (North-East Atlantic)

The influence of microhabitat type on the diversity and community structure of the harpacticoid copepod fauna associated with a cold-water coral degradation zone was investigated in the Porcupine Seabight (North-East Atlantic). Three substrate types were distinguished: dead fragments of the cold-water coral Lophelia pertusa, skeletons of the glass sponge Aphrocallistes bocagei and the underlying sediment. At the family level, it appears that coral fragments and underlying sediment do not harbour distinctly different assemblages, with Ectinosomatidae, Ameiridae, Pseudotachidiidae, Argestidae and Miraciidae as most abundant. Conclusions on assemblage structure and diversity of the sponge skeletons are limited as only two samples were available. Similarity analysis at species level showed a strong variation in the sediment samples, which did not harbour a distinctly different assemblage in opposition to the coral and sponge samples. Several factors (sediment infill on the hard substrates, mobility of the copepods, limited sample sizes) are proposed to explain this apparent lack of a distinct difference between the microhabitats. Coral fragments and sediment were both characterised by high species diversity and low species dominance, which might indicate that copepod diversity is not substantially influenced by hydrodynamical stress. The additive partitioning of species diversity showed that by adding locations species richness was greatly enhanced. The harpacticoid community in the cold-water coral degradation zone is highly diverse and includes 157 species, 62 genera and 19 families. Information from neighbouring soft-bottom regions is necessary to assess whether total species diversity is increased by the presence of these complex habitat-providing substrates.     

Subsurface microbiology and biogeochemistry of a deep, cold-water carbonate mound from the Porcupine Seabight (IODP Expedition 307)

The Porcupine Seabight Challenger Mound is the first carbonate mound to be drilled (∼270 m) and analyzed in detail microbiologically and biogeochemically. Two mound sites and a non-mound Reference site were analyzed with a range of molecular techniques [catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH), quantitative PCR (16S rRNA and functional genes, dsrA and mcrA ), and 16S rRNA gene PCR-DGGE] to assess prokaryotic diversity, and this was compared with the distribution of total and culturable cell counts, radiotracer activity measurements and geochemistry. There was a significant and active prokaryotic community both within and beneath the carbonate mound. Although total cell numbers at certain depths were lower than the global average for other subseafloor sediments and prokaryotic activities were relatively low (iron and sulfate reduction, acetate oxidation, methanogenesis) they were significantly enhanced compared with the Reference site. In addition, there was some stimulation of prokaryotic activity in the deepest sediments (Miocene, > 10 Ma) including potential for anaerobic oxidation of methane activity below the mound base. Both Bacteria and Archaea were present, with neither dominant, and these were related to sequences commonly found in other subseafloor sediments. With an estimate of some 1600 mounds in the Porcupine Basin alone, carbonate mounds may represent a significant prokaryotic subseafloor habitat.     

A new genus and species of Epsilonematidae (Nematoda) from New Caledonia

Akanthepsilonema helleouetae gen. et sp.n. (Epsilonematidae) is described from supralittoral marine sediments in New Caledonia. Its main features are a heterogeneous cuticule with large horn-like dorsal spines and a field of copulatory horns in the male. The taxonomic position of the new genus within the family is discussed.     

Four new species of the genus Perepsilonema Lorenzen, 1973 (Nematoda,Epsilonematidae) from the bay of Calvi (Corsica,Mediterranean)

Four new species of the genus Perepsilonema are described. They are characterized by general habitus, cuticular ornamentation, shape and sexual dimorphism of the amphideal fovea, shape and number of ventral copulatory spines and the shape of the spicules. The female genital system comprises two reflexed ovaries, a left and a right spermatheca and a median uterine chamber filled with sperm cells. The distal part of the uteri have secretory wall cells which contain in some specimen spherical refractive bodies.     

Epsilonematidae (Nematoda) from Chiloé (southern Chile), with descriptions of two new species

From a sandy beach in southern Chile (Quellón Viejo, Chiloé Island) five species of the nematode family Epsilonematidae are described or redescribed: Bathyepsilonema spongiosum sp.n., Epsilonema dentaturn Lorenzen, 1973, E. serrulatum Lorenzen, 1973, Metepsilonema chilotum sp.n. and M. leptaleum Lorenzen, 1973. In the studied beach Epsilonematidae represent up to 33% of the interstitial nematodes. Epsilonema dentaturn is the most common species; in most of the samples, it represents more than 50% of all Epsilonematidae found. The epsilonematids occur mainly in a narrow zone at the midtidal level.     

Leptepsilonema gen. n. (Nematoda, Epsilonematidae) from Chile and the Caribbean Sea

The new genus Leptepsilonema is erected. L. procerum sp.n from intertidal sandy beaches of the Caribbean sea and L. macrum sp.n. and L. exile sp.n. from Chile are described. Postembryonal development of L. procerum , covering the juvenile stages II-IV, is presented. Some ecological data are added.     

The species of the genus Platycheirus Lepeletier & Serville, 1828 (Diptera,Syrphidae) from Taiwan,with a discussion on intersex specimens

Following an international Diptera expedition in 2016, two new species of Platycheirus Lepeletier & Serville, 1828 were found in Taiwan. A total of three species from three different species groups are now known from Taiwan. The two new species, Platycheirus ferrumitarsis sp. n. and Platycheirus perpes sp. n., are described and their respective placement within the peltatus and ambiguus species groups is discussed. The other species, Platycheirus formosanus Shiraki, 1930, is illustrated and its placement is discussed. It is argued that P. nigritus Huo, Ren & Zheng 2007 should be considered a nomen dubium as it is discussed to be described based on an intersex specimen.     

New data on Longidorus aetnaeus Roca, Lamberti, Agostinelli & Vinciguerra, 1986 (Nematoda: Longidoridae) from Iran and Ajaria (Georgia)

Longidorus aetnaeus Roca, Lamberti, Agostinelli & Vinciguerra, 1986 is reported for the first time from Iran and Ajaria (Georgia). Morphological and morphometric data are provided for two Iranian and one Ajarian populations. The D2–D3 region of 28S rDNA for both Iranian populations was sequenced for the first time and the data reported. A detailed study of juveniles of L. aetnaeus from Iran, Georgia and Bulgaria demonstrated that this species develops through three juvenile stages. Furthermore, phylogenetic studies inferred from sequences for the D2–D3 region of 28S rRNA gene revealed that L. aetnaeus is most closely related to L. leptocephalus.     

Pioneer settlement of the cold-water coral Desmophyllum dianthus (Esper, 1794) on plastic

Coral Reefs - Larval settlement is a critical step for sessile benthic species such as corals, whose ability to thrive on diverse natural and anthropogenic substrates may lead to a competitive...     

A new species of the genus Spiroxys (Nematoda; Spiruroidea) from Australian chelonians of the genus Chelodina (Chelidae)

Summary Spiroxys chelodinae n. sp. is described from Australia in three species of freshwater chelonian, Chelodina longicollis, C. expansa and C. oblonga and from New Guinea in an unidentified freshwater chelonian. S. chelodinae differs from other species of the genus in having pseudolabia each with a blunt, prominent, cuticular projection (tooth) on the middle lobe and no other cuticular prominences, a cuticular collar without spines or protrusions, and a gubernaculum with tubes through which the spicules pass. Larvae (probably fourth-stage larvae of S. chelodinae) are also described. This is the first record of a Spiroxys sp. from the Australian Region, and from a host group (suborder Pleurodira), which has a Gondwana distribution. This is discussed in relation to the zoogeography of the genus Spiroxys and it is postulated that Australian chelids acquired this parasite from non-marine cryptodires (possibly carettochelyids or trionychids). In addition, a Spiroxys sp. is recorded from Nigeria, constituting the first such record from the Ethiopian Region. It was found in Pelusius subniger, thus constituting the second record of a Spiroxys species in a pleurodire.     

On the species status of the root-knot nematode Meloidogyne ulmi Palmisano & Ambrogioni, 2000 (Nematoda,Meloidogynidae)

The root-knot nematode Meloidogyne ulmi is synonymised with Meloidogyne mali based on morphological and morphometric similarities, common hosts, as well as biochemical similarities at both protein and DNA levels. M. mali was first described in Japan on Malus prunifolia Borkh.; and M. ulmi in Italy on Ulmus chenmoui W.C. Cheng. Morphological and morphometric studies of their holo- and paratypes revealed important similarities in the major characters as well as some general variability in a few others. Host test also showed that besides the two species being able to parasitize the type hosts of the other, they share some other common hosts. Our study of the esterase and malate dehydrogenase isozyme phenotypes of some M. ulmi populations gave a perfectly comparable result to that already known for M. mali. Finally, phylogenetic studies of their SSU and LSU rDNA sequence data revealed that the two are not distinguishable at DNA level. All these put together, leave strong evidences to support the fact that M. ulmi is not a valid species, but a junior synonym of M. mali. Brief discussion on the biology and life cycle of M. mali is given. An overview of all known hosts and the possible distribution of M. mali in Europe are also presented.     

Study of the genus Plectus Bastian, 1865 (Nematoda: Plectidae) from Iran

Three species of Plectus Bastian, 1865 viz., P. aquatilis and P. pusillus from Kerman province and P. velox from Alborz province, Iran are described and illustrated. Partial sequences of 18S region of ribosomal DNA gene were amplified for P. aquatilis and P. pusillus. The Blast results of population of P. aquatilis from Iran showed 8–10 nucleotides differences with populations of the same species (AF036602; GQ892827; AY284700) reported from the UK, Belgium and The Netherlands, respectively. Whereas Iranian population of P. pusillus showed 14–16 nucleotides differences with P. cf. pusillus (AY284705; AY284704) reported from The Netherlands. Molecular analysis revealed close relationship of the Iranian plectids with P. cf. parvus (AY284699) reported from The Netherlands. Phylogenetic relationships with other related species in the genus Plectus and closely related genera that are available in the GenBank are given.     

Megadraconema cornutum, a new genus and species from Korea, with a discussion of its classification and relationships within the family Draconematidae (Nematoda, Desmodorida) based on morphological and molecular characters

A new genus and species of Draconematidae Filipjev, 1918, Megadraconema cornutum gen. nov., sp. nov., inhabiting subtidal sediments in Jejudo, Korea is described. Megadraconema cornutum gen. nov., sp. nov. is mainly characterized by a long body (1630-2220 μm), presence of a transverse circle of well-developed papillae-like cuticular protrusions at the base of the lip region, a head capsule with reticular structure of subcuticle, an amphid with a pore-like opening, and an internal, bar-shaped fovea. The diagnosis of the family Draconematidae is emended and a key to genus is provided based on their major differential diagnostic characteristics, summarized in a table. Phylogenetic relationships of all the genera within the Draconematidae are discussed for the first time, based on molecular analyses and morphological features. The phylogenetic position of the new genus and relationships within the family Draconematidae based on analysis of molecular sequence data are examined. Analysis of 18S rRNA gene sequences does not support the currently accepted classification, and indicates paraphyly of the subfamily Draconematinae.