Two new species of Parahesione (Annelida: Hesionidae) associated with ghost shrimps (Crustacea: Decapoda) and their phylogenetic relationships

Two new species of Hesionidae, Parahesione pulvinata sp. nov. and Parahesione apiculata sp. nov. are described based on materials collected at tidal flats in Okinawa (Japan) from burrows of the ghost shrimps Neocallichirus jousseaumei and Glypturus armatus. The two new species are characterized by having eight enlarged cirri, dorsal cirrophores with dorsal foliose lobe and biramous parapodia, and by lacking median antenna. Parahesione apiculata sp. nov. has digitate lobes on the posterior margin of the dorsal foliose lobe (absent in P. pulvinata sp. nov.). The two new species were never found outside the ghost shrimp burrows, suggesting they are obligate symbionts. Phylogenetic analyses based on four concatenated genes suggest that the symbiotic lifestyle has evolved several times in Hesionidae.

A New Species of Branchellion (Hirudinea: Piscicolidae) Parasitizing the Gills of Short-Tail Stingrays (Batoidea: Dasyatidae) from the West Pacific

A new fish leech, Branchellion brevicaudatae sp. n., is described based on specimens parasitizing the gills of the short-tail stingray, Bathytoshia brevicaudata (Hutton, 1875), collected from Japanese waters. The new species can be distinguished from other congeners by having: i) pulsating vesicles emerging from posterior base of branchiae, one pair per somite; ii) dorsal white spots, not arranged in longitudinal row; and iii) blackish body. A phylogenetic tree based on partial sequences of the mitochondrial cytochrome c oxidase subunit I gene from the new species and other piscicolid worms showed that the new species is sister to Branchellion torpedinis Savigny, 1822. This is the first record of Branchellion Savigny, 1822 from Japanese waters.

From commensalism to parasitism within a genus-level clade of barnacles

Understanding how animals evolve to become parasites is key to unravelling how biodiversity is generated as a whole, as parasites could account for half of all species richness. Two significant impediments to this are that parasites fossilize poorly and that they retain few clear shared morphological features with non-parasitic relatives. Barnacles include some of the most astonishingly adapted parasites with the adult body reduced to just a network of tubes plus an external reproductive body, but how they originated from the sessile, filter-feeding form is still a mystery. Here, we present compelling molecular evidence that the exceedingly rare scale-worm parasite barnacle Rhizolepas is positioned within a clade comprising species currently assigned to Octolasmis, a genus exclusively commensal with at least six different phyla of animals. Our results imply that species in this genus-level clade represent an array of species at various transitional stages from free-living to parasitic in terms of plate reduction and host-parasite intimacy. Diverging only about 19.15 million years ago, the route to parasitism in Rhizolepas was associated with rapid modifications in anatomy, a pattern that was likely true for many other parasitic lineages.

Theama japonica sp. nov., an Interstitial Polyclad Flatworm Showing a Wide Distribution along Japanese Coasts

We establish a new interstitial polyclad species, Theama japonica sp. nov., based on specimens collected from coarse-sandy habitats in three Japanese main islands (Hokkaido, Honshu, and Shikoku) along the coasts of the Pacific Ocean and the Sea of Japan. Theama japonica is characterized by i) two pairs of cerebral eyespots and four to six precerebral eyespots; ii) eosinophilic secretion glands distributed in the distal half of the inner ventral part of the prostatic vesicle; iii) a conical penis papilla, bent up dorsally, with a sclerotized inner wall; iv) the prostatic sheath with an inner angular fold on the dorso-distal side; and v) the external cilia longer dorsally than ventrally. Partial sequences of the cytochrome c oxidase subunit I (COI) gene from 20 specimens collected at eight localities along Japanese coasts represented 19 haplotypes. The uncorrected p-distances among these COI haplotypes fell within intraspecific variations observed in other polyclads. A network analysis based on these COI haplotypes suggested a geographically non-cohesive genetic structure of the species, possibly indicating the species' high dispersibility. Molecular phylogenetic analyses based on a concatenated dataset of 18S and 28S rDNA sequences showed T. japonica formed a clade with other Theama species. The resulting tree also indicates that our new species is more closely related to Theama sp. from Colombia than species from Panama and Croatia.

Investigating the diversity of bioluminescent marine worm Polycirrus (Annelida), with description of three new species from the Western Pacific

Bioluminescence, a phenomenon observed widely in organisms ranging from bacteria to metazoans, has a significant impact on the behaviour and ecology of organisms. Among bioluminescent organisms, Polycirrus, which has unique emission wavelengths, has received attention, and advanced studies such as RNA-Seq have been conducted, but they are limited to a few cases. In addition, accurate species identification is difficult due to lack of taxonomic organization. In this study, we conducted comprehensive taxonomic survey of Japanese Polycirrus based on multiple specimens from different locations and described as three new species: Polycirrus onibi sp. nov., P. ikeguchii sp. nov. and P. aoandon sp. nov. The three species can be distinguished from the known species based on the following characters: (i) arrangement of mid-ventral groove, (ii) arrangement of notochaetigerous segments, (iii) type of neurochaetae uncini, and (iv) arrangement of nephridial papillae. By linking the bioluminescence phenomenon with taxonomic knowledge, we established a foundation for future bioluminescent research development. We also provide a brief phylogenetic tree based on cytochrome c oxidase subunit I (COI) sequences to discuss the evolution of bioluminescence and the direction of future research.

Four new species of coral- and rock-boring polychaetes Daylithos (Annelida, Flabelligeridae) from the Pacific Ocean

Four new species of Daylithos (Flabelligeridae, Annelida) are described, based on specimens collected from rocks and corals of Japan and Malaysia. Daylithos, contains one species, D. parmatus, currently reported from Japan. However, the specimens described in previous reports were unable to be located and thus deemed lost. Therefore, it was unclear whether the specimens described as D. parmatus in those studies were, indeed, the species. In Malaysia, D. parmatus has also been known as popular species from corals. The specimens collected from Langkawi (Malaysia) showed clearly different characters from D. parmatus and other congeners. In this study, we describe four new species, Daylithos japonicus, D. amamiensis, D. sugashimaensis and D. langkawiensis, based on newly-collected specimens from several part of Japan and Malaysia. These new species can be discriminated from other congeners by body colour, presence of eyes, shape of dorsal shield, length of caruncle and arrangement of neurochaetae. We have also provided mitochondrial cytochrome c oxidase subunit I sequences of the new species.

Taxonomic revision of the free-living marine nematode genus Deontostoma (Enoplida: Leptosomatidae) and inclusion of a new species from the Southern Ocean

A new species of free-living marine nematode, Deontostoma quadridentatum sp. nov., is described from a deep-sea sediment sample collected off the South Orkney Islands, the Southern Ocean, during a cruise (KH-19-6-Leg 4) conducted on the R/V Hakuho-Maru. Deontostoma quadridentatum sp. nov. differs from its congeners by the possession of: i) a cephalic capsule with a smooth posterior edge and without intralobar lacunae; ii) interlobar fenestrae with two posterior incisions; iii) four odontia on each mandible; iv) three onchia; v) spicules with velum and lateral process; vi) gubernacula with a hollow triangular crus, vii) one ventromedian supplement; viii) two precloacal subventral rows consisting of 8-10 setae and 12-20 papillae; and ix) by the lack of ocelli. Partial 18S rRNA and cytochrome c oxidase subunit I gene sequences were determined for D. quadridentatum sp. nov., and the diagnosis of Deontostoma and the dichotomous keys to the subfamilies of Leptosomatidae, genera of Deontostomatinae, and species of Deontostoma were revised. Two known species, Triceratonema montredonense comb. nov. and Triceratonema papillosum comb. nov., were transferred from Deontostoma. Our molecular phylogenetic analysis did not clarify the position of Deontostoma quadridentatum sp. nov., but we placed this species into Deontostoma based on morphological observations. We also tried to find a relationship between distribution and morphological characteristic because it seems that there are two phylogenetic lineages that exist in Deontostoma based on the distribution of all species. However, no such relationships could be found from our literature survey.

Worm on worm: Two rare genera of Calamyzinae (Annelida, Chrysopetalidae), with a description of new species

Marine annelids in the subfamily Calamyzinae (family Chrysopetalidae) are either symbiotic or free-living forms that have been mainly reported from deep-sea chemosynthetic environments. Symbiotic calamyzines predominantly live in the mantle cavity of bivalves distributing at hydrothermal vents or methane seeps except for two species inhabiting the epidermis of polychaetes and octopuses. In this study, we describe a new species, Calamyzas crambon sp. nov., from Japan and report a new record of Nautiliniella calyptogenicola from the Mariana Trench. We also provide the phylogenetic position of the two species within Chrysopetalidae based on four gene markers (COI, 16S, 18S, and H3).

A new species of the Spirobranchuskraussii complex, S.akitsushima (Annelida, Polychaeta, Serpulidae), from the rocky intertidal zone of Japan

A new species of Spirobranchus (Annelida: Serpulidae) is described based on specimens collected at the coastal Shonan area of Sagami Bay and the adjacent areas of Honshu, Japan. Spirobranchusakitsushima sp. nov. forms large aggregations in the intertidal rocky zone of warm-temperate Japanese shores. This species was referred to as Pomatoleioskraussii (Baird, 1864) until the monotypic genus Pomatoleios was synonymized with Spirobranchus. This new species is formally described based on morphologically distinct Japanese specimens with supporting DNA sequence data. The calcareous opercular endplate of Spirobranchusakitsushima sp. nov. lacks a distinct talon, but some specimens have a slight rounded swelling on the endplate underside, while in other species of the S.kraussii complex a talon is present, usually extended, and with bulges. We examined sub-fossil tube aggregations of the new species and suggest that such aggregation stranded ashore is a good indicator of vertical land movements (uplift and subsidence) resulting from past events, such as earthquakes, in Honshu, Japan.

Four new species of Ctenodrilus, Raphidrilus, and Raricirrus (Cirratuliformia, Annelida) in Japanese waters, with notes on their phylogenetic position

Four new species of annelids, Ctenodrilus japonicus sp. nov., Raphidrilus misakiensis sp. nov., Raphidrilus okinawaensis sp. nov., and Raricirrus anubis sp. nov., are described based on specimens collected from Japanese waters. Ctenodrilus japonicus sp. nov. inhabits the interstitial environment and can be distinguished from the other congeners by the following features: (i) total of 16 chaetigers, (ii) chaetigers 1-3 with stout hooks, (iii) minute body (approximately 1 mm in length), (iv) all parapodia with the same number of chaetae (two notochaetae; two neurochaetae), and (v) presence of dorsal and ventral papillae. Raphidrilus misakiensis sp. nov. lives under intertidal stones and can be distinguished from other congeners by having pectinate neurochaetae. Raphidrilus okinawaensis sp. nov. inhabits the interstitial environment and can be distinguished from other congeners by: (i) absence of annulation on the peristomium and achaetous segment and (ii) presence of a heart body in chaetigers 4-5. Raricirrus anubis sp. nov. inhabits whale bones and can be distinguished from other congeners by the following features: (i) presence of a heart body in chaetigers 9-14, (ii) presence of capillary neurochaetae on chaetiger 1, and (iii) presence of simple curved spines. A phylogenetic tree based on partial sequences of cytochrome c oxidase subunit I and 16S rRNA from the new species and other cirratulid worms showed that Raphidrilus is included in Cirratuliformia. This is the first record of Raphidrilus and Raricirrus from Japanese waters.

First record of the decapod-egg predator Ovicides paralithodis (Nemertea, Carcinonemertidae) from the snow crab Chionoecetes opilio (Decapoda, Brachyura)

The carcinonemertid monostiliferan Ovicides paralithodis Kajihara and Kuris, 2013 was originally described as an egg predator of the red-king crab Paralithodes camtschaticus (Tilesius, 1815) in the Sea of Okhotsk, the Bering Sea, and the Gulf of Alaska. In the present study, several carcinonemertid specimens were obtained from the egg mass of the snow crab Chionoecetes opilio (O. Fabricius, 1788) in the Sea of Japan. Partial sequences of the mitochondrial cytochrome c oxidase subunit I gene (COI) determined from two specimens of the carcinonemertid were identical with a barcode sequence from the holotype of O. paralithodis, indicating that the host range of the species covers at least the two decapod species, P. camtschaticus and C. opilio.

Ramisyllis kingghidorahi n. sp., a new branching annelid from Japan

Among over 20,000 species of Annelida, only two branching species with a highly modified body-pattern are known until now: the Syllidae Syllis ramosa McIntosh, 1879, and Ramisyllis multicaudata Glasby et al. (Zoological Journal of the Linnean Society, 164, 481–497, 2012). Both have unusual ramified bodies with one head and multiple branches and live inside the canals of host sponges. Using an integrative approach (combining morphology, internal anatomy, ecology, phylogeny, genetic divergence, and the complete mitochondrial genome), we describe a new branching species from Japan, Ramisyllis kingghidorahi n. sp., inhabiting an undescribed species of Petrosia (Porifera: Demospongiae) from shallow waters. We compare the new species with its closest relative, R. multicaudata; emend the diagnosis of Ramisyllis; and discuss previous reports of S. ramosa. This study suggests a much higher diversity of branching syllids than currently known. Finally, we discuss possible explanations for the feeding behaviour in the new species in relation to its highly ciliated wall of the digestive tubes (especially at the distal branches and anus), and provide a hypothesis for the evolution of branching body patterns as the result of an adaptation to the host sponge labyrinthic canal system.

Violet bioluminescent Polycirrus sp. (Annelida: Terebelliformia) discovered in the shallow coastal waters of the Noto Peninsula in Japan

Terebellidae worms have large numbers of tentacles responsible for various biological functions. Some Terebellidae worms whose tentacles emit light are found around the world, including exceptional violet-light-emitting Polycirrus spp. found in Europe and North America. However, there is no video-recorded observation of the luminous behavior of such unique species in nature, and the genetic information related to their ecology are lacking. Here, for the first time, we video-recorded the violet-light-emitting behavior of an undescribed Japanese worm in its natural habitat. The worm was designated as Polycirrus sp. ISK based on morphological observations, and the luminescence spectrum showed a peak at 444 nm, which is an exceptionally short wavelength for bioluminescence in a shallow coastal water environment. An analysis of differentially expressing genes based on separate RNA-Seq analysis for the tentacles and the rest of body revealed the specific expression of genes that are probably involved in innate immunity in the tentacles exposed to predators. We also found a Renilla luciferase homologous gene, but coelenterazine was not detected in the worm extract by analyses using a liquid chromatography and a recombinant Renilla luciferase. These results will promote an understanding of the ecology and luminescence mechanisms of luminous Polycirrus spp.

Annelids of the eastern Australian abyss collected by the 2017 RV 'Investigator' voyage

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV 'Investigator' voyage 'Sampling the Abyss'. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world's ocean will act as a springboard for future taxonomic and biogeographic studies in the area.

Black spicules from a new interstitial opheliid polychaete Thoracophelia minuta sp. nov. (Annelida: Opheliidae)

The phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species' body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species' spicules and also the species' progenetic origin.

A new nemertean with a branched proboscis, Gorgonorhynchus citrinus sp. nov. (Nemertea: Pilidiophora), with molecular systematics of the genus

Among ~1300 species of world nemerteans, seven species in five genera of lineid heteronemerteans have been known to possess a branched proboscis. In this paper, we describe the eighth branched-proboscis species: Gorgonorhynchus citrinus sp. nov. from Okinawa, Japan. We also report Gorgonorhynchus cf. repens Dakin & Fordham, 1931 with uniformly orange body, as a new member for the Japanese nemertean fauna. We infer the phylogenetic relationships between these forms and other members of Lineidae McIntosh, 1874 for which partial sequences of the mitochondrial 16S rRNA and cytochrome c oxidase subunit I, and the nuclear 18S rRNA, 28S rRNA, and histone H3 genes are available in public databases, along with newly sequenced data of another branched-proboscis heteronemertean, Polydendrorhynchus zhanjiangensis (Yin & Zheng, 1984) from China. In the resulting tree, Gorgonorhychus Dakin & Fordham, 1931 was sister group to non-branched-proboscis Dushia Corrêa, 1963, whereas P. zhanjiangensis was sister group to likewise non-branched-proboscis Cerebratulus lacteus (Leidy, 1851). http://zoobank.org/urn:lsid:zoobank.org:pub:685992C5-F595-4C28-9178-256D945E595A

Description of Pericelis flavomarginata sp. nov. (Polycladida: Cotylea) and its predatory behavior on a scaleworm

We describe a new species of polyclad flatworm, Pericelis flavomarginata sp. nov., from the intertidal and subtidal zones along localities on the Pacific coast of Japan. Pericelis flavomarginata sp. nov. is characterized by i) the dorsal surface of the body fringed by a lemon-yellow line except for the tip of tentacles, with a narrow brown midline running from the anterior edge of the body to the posterior end of the pharynx, ii) the pair of marginal tentacles with the tips extending and tapering, and iii) the presence of a common gonopore. Our molecular phylogenetic analysis revealed that selected Pericelis species were divided into two clades, each of which may be agreed with a characteristic dorsal color pattern. Additionally, we report an observation on the feeding behavior of P. flavomarginata sp. nov. on the polychaete Iphione muricata (Savigny in Lamarck, 1818).

Two new species of Fauveliopsidae (Annelida, Sedentaria) from submarine caves and deep sea, Japan

Two new species of fauveliopsid annelids, Fauveliopsis antri sp. nov. and Laubieriopsis soyoae sp. nov., are described based on specimens collected from Japanese waters. Fauveliopsis antri sp. nov. inhabits submarine caves and can be discriminated from the other congeners by the following features: i) 32 chaetigers, ii) chaetigers 1-3 with stout hooks, iii) minute body (about 1 mm in length), iv) all parapodia with same number of chaetae (2 notochaetae; 2 neurochaetae), and v) presence of dorsal and ventral papillae. Laubieriopsis soyoae sp. nov. inhabits deep water sediments and can be distinguished from the other congeners by: i) 24 chaetigers, ii) chaetigers 1-3 without annulations, and iii) acicular chaetae with tips entire, without denticles.

A new deep-sea species of Flabelligena from off the South Orkney Islands, the Southern Ocean

Background

A new acrocirrid species, Flabelligenahakuhoaesp. nov., is described from off the South Orkney Islands, the Southern Ocean. Individuals of the new species were collected by rock dredging, 2036–2479 m in depth.

New information

The new species can be distinguished from its congeners by the number of branchiae, position and length of paired ventral large papillae and length of body papillae.

A new marine tardigrade genus and species (Arthrotardigrada, Styraconyxidae) with unique pockets on the legs

A marine heterotardigrade Cyaegharctus kitamuraigen. et sp. nov. (Arthrotardigrada, Styraconyxidae) is described from Daidokutsu, a submarine cave off Iejima island, Okinawa Islands, Ryukyu Archipelago, Japan. It is easily distinguished from all other styraconyxids by its pocket organs (putative sensory structures) on all legs in addition to the usual leg sensory organs. Its combination of other character states, such as the dorso-ventrally flattened body, ovoid primary clavae, conical secondary clavae, large terminal anus, internal digits with proximal pads and peduncles, external digits with developed peduncles and all digits with three-pointed claws in adult female, supports the erection of a new genus and species.

First records of Brada kudenovi Salazar-Vallejo, 2017 (Annelida, Flabelligeridae) from Japan

We reassess two specimens, part of the late Dr Minoru Imajima’s collections, from Japan of the flabelligerid genus Brada Stimpson, 1853. We re-identify the specimens as B. kudenovi Salazar-Vallejo, 2017 and newly record this species from Japan, which represents the southernmost locality of the genus worldwide. The specimens were previously reported as B. inhabilis (Rathke, 1843), which has Molde, Norway as its type locality. However, the morphological features are identical to the original description of B. kudenovi in the following: the body is whitish in alcohol; there are one or two multiarticulate notochaetae per parapodium; the neuropodial lobes are low, not projecting; and the body papillae are short.

Life Cycle of the Japanese Green Syllid, Megasyllis nipponica (Annelida: Syllidae): Field Collection and Establishment of Rearing System

Some polychaete species in the family Syllidae exhibit distinctive life cycles, in which a posterior part of the body of an individual detaches as a reproductive individual called a "stolon". This type of reproductive mode is known as stolonization or schizogamy. Although a number of observations have been reported, and techniques using molecular markers have recently been applied to characterize this phenomenon, little is known about the developmental and physiological mechanisms underlying stolonization. In the present study, Megasyllis nipponica, a common syllid species distributed throughout Japan, is proposed as a model to reveal the developmental and physiological mechanism of stolonization, and the rearing system to maintain it in laboratory conditions is described. This species was repeatedly sampled around Hokkaido, where more dense populations were found from August to October. The animals were maintained in the laboratory under stable long-day condition (20°C, 16L:8D), and fed mainly with spinach powder. Stolonization processes, spawning, embryonic and postembryonic development were observed and documented, and the required period of time for each developmental stage was recorded. The complete generation time was around two months under the rearing condition. The information provided is valuable to maintain this and other syllid species in the laboratory, and hence contributes to the establishment of new evolutionary and developmental research lines in this group of annelids.

New record of the hydrothermal vent-endemic polychaete Archinome jasoni Borda et al., 2013 (Annelida, Amphinomidae) from the Northwest Pacific

The hydrothermal vent-endemic polychaete Archinome jasoni Borda et al., 2013 is known from the Atlantic, Indian, and Southwest Pacific oceans. In this study, we report A. jasoni from Okinawa Trough, Japan, which represents the first record of this species and the genus from the Northwest Pacific. We determined 16S and 28S rRNA gene sequences from 1 of the 7 specimens collected. We compared our Northwest Pacific specimens to specimens from the Southwest Pacific, Atlantic, and Indian oceans, and our specimen was genetically most closely related to individuals from the Southwest Pacific.

Bioluminescence properties of Thelepus japonicus (Annelida: Terebelliformia)

Terebelliformia is a benthic group of marine annelid worms. The bioluminescence of several species has been reported in taxonomical and histological literature, but very little information is known about the biochemical aspects of this phenomenon. In this study, we examined the basic properties of the luminescence system using an extract of the Japanese terebelliform worm, Thelepus japonicus. The bioluminescence extract was soluble in water, and emitted blue-green light at λ_max 508 nm following the addition of divalent cations. This triggering action was highly specific to Fe²⁺ and addition of ATP, H₂ O₂ or coelenterazine did not enhance activity. The bioluminescence was inactivated by heat treatment and organic solvents, indicating the involvement of a protein component. These results suggested that Thelepus worm produces light using a novel system that differs from that in other known luminescent annelids.

New species of bone-eating worm Osedax from the abyssal South Atlantic Ocean (Annelida, Siboglinidae)

A new species of bone-eating annelid, Osedaxbraziliensis sp. n., found in a sunken whale carcass at a depth of 4,204 m at the base of the São Paulo Ridge in the South Atlantic Ocean off the Brazilian coast is described. The organism was retrieved using the human-occupied vehicle Shinkai 6500 during the QUELLE 2013 expedition. This is the 26^th species of the genus and the first discovery from the South Atlantic Ocean, representing the deepest record of Osedax worldwide to date. This species morphologically resembles Osedaxfrankpressi but is distinguished by the presence of a yellow bump or patch behind the prostomium and its trunk length. Molecular phylogenetic analysis using three genetic markers (COI, 16S, and 18S) showed that O.braziliensis sp. n. is distinct from all other Osedax worms reported and is a sister species of O.frankpressi.

New annelid species from the deepest known whale-fall environment: Bathykermadeca thanatos sp. nov. (Annelida: Polynoidae)

A new species of polynoid annelids, Bathykermadeca thanatos sp. nov., is described based on specimens collected from sunken whale bones in the Nansei-Shoto Trench in the Philippine Sea at a depth of 4974 m. The cetacean-carcass community at the site exceeds the deepest record reported to date. This new species can be distinguished from other members of the genus by the following features: i) there is only one type of neurochaetae, ii) the teeth lack serration and grow inwardly, iii) median antenna extends beyond the tip of frontal filament, iv) nephridial papillae are present in segments 12-15, and v) there are about 50 notochaetae in each parapodium.

A new species of the rare, deep-sea polychaete genus Benthoscolex from the Sea of Kumano, Japan (Annelida, Amphinomidae)

A new species of amphinomid polychaete, Benthoscolexseisuiaesp. n., is described from the Sea of Kumano, Japan, from depths of 487–596 m. The species is distinguishable from its congeners by the following features: i) palps 1.8 times as long as lateral antennae; ii) branchiae do not reach to the tip of the notochaetae. This is the first record of Benthoscolex from Japan. A partial mitochondrial cytochrome c oxidase subunit I gene sequence from the holotype of B.seisuiaesp. n. is provided for reliable species identification in the future.

Description of Elisesione imajimai sp. nov. From Japan (Annelida: Hesionidae) and A Redescription of E. problematica (Wesenberg-Lund, 1950) and Its Confirmation Within Hesionini

Naoto Jimi, Danny Eibye-Jacobsen, and Sergio I. Salazar-Vallejo (2018) Elisesione imajimai sp. nov. is newly described based on specimens collected in Sagami Bay, Japan, at a depth of 150-250 m. This new species resembles E. problematica (Wesenberg-Lund, 1950) from Iceland, but differs because in E. imajimai sp. nov. the ventral cirri surpass the tips of the neurochaetal lobes, reaching to the medial part of the neurochaetal bundle; the palps are 1/2-4/5 as long as the antennae; the aciculae are pale brownish; and the dorsal integument shows 9-10 transverse wrinkles per segment, whereas in E. problematica the ventral cirri hardly reach the tips of the neurochaetal lobes; the palps are as long as the antennae; the aciculae are black; and there are 15 transverse wrinkles per segment. A morphological redescription of E. problematica based on its type material and a revised key to identify species in the genus are also provided. A phylogenetic analysis based upon four genes (COI, 16S, 18S, 28S) confirms its position within Hesionini.

Remarkable biodiversity of flabelligerids in Japan: seven new species of <i>Diplocirrus</i> (Annelida: Flabelligeridae) from Japanese waters

Seven new species of Diplocirrus are described from Japan: D. asamushiensis sp. nov., D. imajimai sp. nov., D. mamoi sp. nov., D. ohtsukai sp. nov., D. seisuiae sp. nov., D. tohokuensis sp. nov., and D. toyoshioae sp. nov. These species are distinguished from all the known species of Diplocirrus by the following features: length of the cephalic cage, length of lateral papillae, presence of gonopodial lobe, adhering pattern of sediment particles, length of caruncle, length and morphological feature of branchiae, articles and morphological features of neurochaetae, and swollen area along the body.

Rare endoparasitic Asteriomyzostomum (Annelida: Asteriomyzostomidae) from Japan, including three new species descriptions and their phylogenetic position within Myzostomida

The rare myzostomid genus Asteriomyzostomum Jägersten, 1940 consists of two species, both parasitizing sea stars. The phylogenetic position of this genus among Myzostomida has not been previously shown using molecular data. In this study, three species of Asteriomyzostomum were collected from the Kumano Sea, Japan, and are described as A. hercules sp. nov., A. jinshou sp. nov., and A. monroeae sp. nov. Additional specimens of the genus Asteromyzostomum Wagin, 1954 were also collected from the Kumano Sea and briefly reported as Asteromyzostomum sp. A molecular phylogeny based on four gene markers (COI, 16S, 18S, H3) suggests that the three families Asteriomyzostomidae, Asteromyzostomidae, and Protomyzostomidae comprise a clade. The resulting topology of the tree indicates that a host change from Crinozoa (sea lilies and feather stars) to Asterozoa (asteroids and ophiuroids) occurred only once in the evolutionary history of Myzostomida.

New species of Trophoniella from Shimoda, Japan (Annelida, Flabelligeridae)

Trophoniella hephaistos sp. n. was collected from a tank irrigated with seawater pumped directly from Nabeta Bay, Japan. This species is discriminated from other Trophoniella by having dorsal tubercles, a tongue-shaped branchial plate, a tunic covered with large sediment grains dorsally and ventrally, having eyes, and anchylosed neurohooks starting from chaetigers 17-20. This is the first record of Trophoniella from Japanese waters. Identification keys to species of Trophoniella and four gene sequences (COI, 16S, 18S, 28S) of this species are provided. Phylogenetic analysis was conducted to clarify phylogenetic position of Trophoniella in Flabelligeridae using four genes.

C-type natriuretic peptide inhibits rat mesangial cell proliferation by a phosphorylation-dependent mechanism

We studied the effects of C-type natriuretic peptide (CNP) on rat cultured mesangial cell proliferation. (1) Exposure to CNP (10 nM-1 microM for 72 h) inhibited [3H]thymidine incorporation into mesangial cells in a concentration-dependent manner. Atrial natriuretic peptide (1 nM-1 microM), a peptide related to CNP, also decreased [3H]thymidine incorporation into these cells in a concentration-dependent manner. (2) Both CNP (10 nM- microM) and atrial natriuretic peptide (10 nM-1 microM) also decreased mesangial cell number. (3) The cyclic GMP analog, 8-bromo-cyclic GMP (100 microM and 1 microM), mimicked the inhibitory effects of CNP and atrial natriuretic peptide on [3H]thymidine incorporation into mesangial cells, whereas inhibitors of protein kinase C, protein kinase A, and protein kinase G reduced the effect of both natriuretic peptides. Moreover, the phosphatase inhibitor, calyculin A, increased [3H]thymidine incorporation into mesangial cells. (4) CNP and atrial natriuretic peptide decreased interleukin-1-, interleukin-6-, platelet derived growth factor-, angiotensin II-induced [3H]thymidine incorporation into mesangial cells. These results suggest that CNP exerts inhibitory effects on mesangial cell proliferation and that this effects depend on protein phosphorylation pathways.

Inhibitory effect of the intravenous anesthetic, ketamine, on rat mesangial cell proliferation

We studied the effects of ketamine and propofol on rat cultured mesangial cell (MC) proliferation. The 72-h exposure to ketamine (1-100 microM) inhibited [3H]thymidine incorporation into the MC in a concentration-dependent manner. Propofol, however, was not effective at inhibition of MC proliferation at doses from 1 to 100 microM. Ketamine also decreased the cell number at clinically relevant concentrations and increased adenosine 3',5'-cyclic monophosphate (cAMP) levels in MC. We also studied the effects of ketamine on cytokine-induced [3H]thymidine incorporation into the cells. Ketamine decreased the tumor necrosis factor-alpha (TNF-alpha)-, interleukin 1 (IL-1)-, and interleukin 6 (IL-6)-induced [3H]thymidine incorporation into the cells. It also decreased angiotensin II (Ag II)-induced [3H]thymidine incorporation. These results suggest that ketamine has inhibitory effects on MC proliferation, but that propofol does not. Because ketamine inhibits TNF-alpha-, IL-1-, and IL-6-induced MC proliferation, it may be useful in suppressing the cell growth clinically.

[Pathway of the radial artery located with a small-caliber Doppler probe for arterial cannulation in pediatric patients]

The pathway of the radial artery of 23 patients, ranging in age from 17 days to 10 years, was located with a small-caliber Doppler probe, 1.5 mm in diameter, and the artery was punctured along the pathway traced on the skin surface. In all patients the arterial pathway, including its branch and diameter, was shown clearly. In 11 patients, ranging in weight from 5 to 24 kg, the artery was greater than 0.5 mm in diameter and was cannulated easily. In another 4 patients, all less than 3 kg in weight, the artery under the thin skin layer was cannulated successfully in three of them. However, among the remaining 8 patients, ranging in weight from 3 to 5 kg, cannulation was successful in only two cases. The thick tissue layer, including the skin and the subcutaneous layer over the small artery, was thought to interfere with the accurate location of the artery in the other six patients. Nevertheless, the arterial pathway traced on the skin surface facilitated successful percutaneous cannulation by another method in these six. Visualization of the arterial pathway by the small-caliber Doppler probe was thought to be helpful for percutaneous cannulation, with or without another cannulation method.