Colonial Entoproct Epibiotic on a Sea Spider.

We report an entoproct epibiotic on the surface of a sea spider (Pycnogonida). The pycnogonid was identified as sp. (Nymphonidae).

Trematode metacercariae parasitic in the estuarine crustacean Cyathura muromiensis Nunomura, 1974 (Peracarida: Isopoda: Anthuroidea).

This is the first report of trematodes parasitic in the estuarine isopod crustacean Cyathura muromiensis, and the fourth report from anthuroid isopods worldwide. From 52 of 54 host individuals collected qualitatively on the tidal flat of the Muromi River estuary, Fukuoka, Japan, 389 cysts of metacercariae were extracted (sample prevalence = 96.3 %).

Nectonema horsehair worms (Nematomorpha) parasitic in the Tanner crab Chionoecetes bairdi, with a note on the relationship between host and parasite phylogeny.

Nectonema nematomorphs utilize marine crustacean hosts in their life cycle; 16 decapod and 1 isopod genera have been reported to date as host genera. This study reports the first case of Nectonema parasitic in the Tanner crab Chionoecetes bairdi, adding another known host genus. A single nematomorph juvenile was recovered from the body cavity of each of 2 ovigerous female crabs.

Isopods on isopods: integrative taxonomy of Cabiropidae (Isopoda: Epicaridea: Cryptoniscoidea) parasitic on anthuroid isopods, with descriptions of a new genus and three new species from Japan.

Species in the parasitic isopod family Cabiropidae are known to utilise various isopods as hosts but there are currently no records of members parasitising anthuroid hosts. We describe Anthuroniscus gen. nov.

Ontogenetic Changes in Pigmentation Pattern in (Crustacea: Isopoda: Anthuridae).

Species in the anthurid isopod genus have specific, dorsal dark pigmentation patterning on the body. Though species have traditionally been distinguished mainly by differences in the dorsal pigmentation pattern in females, the stability of the pigmentation pattern within species had not been investigated, and information was lacking on ontogenetic variation in the pattern. Our study showed the following for .

Flatworm cocoons in the abyss: same plan under pressure.

While knowledge of early ontogeny in abyssal animals is highly limited in general, it was completely lacking for abyssal, free-living platyhelminths. We discovered flatworm egg capsules (or 'cocoons') on rocks collected at depths of 6176-6200 m on the abyssal slope of the Kuril-Kamchatka Trench, northwestern Pacific. The egg capsules were black and spherical, around 3 mm in diameter, and contained three to seven individuals ( = 4) at the same developmental stage, either the spherical (putative early embryo) or vermiform (putative late embryo) stages.

Capropodocerus, a new genus in Podoceridae (Crustacea: Amphipoda) from Japan, with descriptions of two new species.

We establish the new podocerid genus Capropodocerus gen. nov. for the two new species Capropodocerus tagamaru gen.

Phototaxis in Two Shallow-Water Species (Crustacea: Tanaidacea).

Different crustacean species can differ in their response to light. In Tanaidacea, a small group of aquatic, benthic crustaceans, previous studies suggested that several species may be positively phototactic based on their attraction to nocturnal light traps, but no experimental investigations of phototaxis had been conducted on this group. Here we show experimentally that two species in the genus are phototactic but exhibit opposite reactions to light; , which inhabits the blades and stipes of seaweeds, was positively phototactic, whereas , which inhabits muddy sediments overlying bedrock, was negatively phototactic.

Diexanthema hakuhomaruae sp. nov. (Copepoda: Siphonostomatoida: Nicothoidae) from the Hadal Zone in the Northwestern Pacific, with an 18S Molecular Phylogeny.

Purpose: Diexanthema copepods are ectoparasites on deep-sea isopods. This genus currently contains six species, all reported from the North Atlantic. Our study describes a new species of Diexanthema found on isopods from 7184 to 7186 m depth in the Kuril-Kamchatka Trench, northwestern Pacific.

A new Sphaeronella species (Copepoda: Siphonostomatoida: Nicothoidae) parasitic on Euphilomedes sp. (Ostracoda: Myodocopa: Philomedidae) from Hokkaido, Japan, with an 18S molecular phylogeny.

With about 80 species, Sphaeronella is the most species-rich genus in the copepod family Nicothoidae. To date, 20 named Sphaeronella species have been reported as ectoparasites on ostracod crustaceans. Here we describe Sphaeronella uyenoi sp.

Observations on Predation in Richardson, 1909 (Isopoda: Cymothoida: Paranthuridae).

Although isopods in Anthuroidea are predators, there is little information on their predatory behavior. In this study, we investigated predation by the paranthurid , which was originally described from northern Japan but has recently been reported as an invasive alien species in western America and Europe. Six crustacean species (two isopods, two amphipods, and two tanaidaceans, one of which does not co-occur with in the wild) and one pycnogonid species were used as prey candidates in our experiments.

Dive into the sea: first molecular phylogenetic evidence of host expansion from terrestrial/freshwater to marine organisms in Mermithidae (Nematoda: Mermithida).

We report the first mermithid nematode found to be parasitic in a marine tanaidacean crustacean. Ten host tanaidaceans were collected from a depth of 52 m in Otsuchi Bay, Iwate, Japan, north-western Pacific, and identified as a species in the tanaidid genus Zeuxo Templeton, 1840. Nematodes occurred in the host's body cavity; in one case, at least two individuals inhabited a single host.

Digenean Metacercariae Parasitic in a Staurozoan Cnidarian.

I report digenean metacercariae from Staurozoa, which were not previously known as digenean hosts. The host species, Kishinouye, 1910, was collected from algae in Oshoro Bay, Hokkaido, Japan, and contained metacercariae in the mesoglea. The metacercariae were encysted; cysts were oval, 93 µm long by 64 µm wide in one live individual.

Description of a New Species, with an 18S Molecular Phylogeny (Crustacea: Tanaidacea: Typhlotanaidae).

We describe a new typhlotanaid species, sp. nov., collected from between 167 and 488 m depth in the Sagami Sea, Japan.

Three Free-Living Marine Nematodes from Sagami Bay, Japan, with a Description of sp. nov. (Nematoda: Oncholaimidae).

We describe three free-living marine nematode species from Sagami Bay, Japan. sp. nov.

Comprehensive Transcriptome Sequencing of Tanaidacea with Proteomic Evidences for Their Silk.

Tanaidaceans are small benthic crustaceans that mainly inhabit diverse marine environments, and they comprise one of the most diverse and abundant macrofaunal groups in the deep sea. Tanaidacea is one of the most thread-dependent taxa in the Crustacea, constructing tubes, spun with their silk, for shelter. In this work, we sequenced and assembled the comprehensive transcriptome of 23 tanaidaceans encompassing 14 families and 4 superfamilies of Tanaidacea, and performed silk proteomics of Zeuxo ezoensis to search for its silk genes.

A new species of Expanathura (Crustacea: Isopoda: Anthuroidea) from Iriomote Island, Japan, with a note on male polymorphism.

We describe Expanathura monile sp. nov. from Iriomote Island, Okinawa, Japan, northwestern Pacific.

First report of marine horsehair worms (Nematomorpha: Nectonema) parasitic in isopod crustaceans.

Nectonema, the only horsehair worm (Nematomorpha) genus found in marine environments, was previously known to be parasitic only in decapod crustaceans. We report Nectonema sp. as the first record of a marine nematomorph parasitic in isopod crustaceans.

sp. nov. (Crustacea: Ostracoda: Cypridoidea) from Japan, with Information on Its Reproductive Mode.

We describe the cypridoidean ostracod sp. nov. from brackish water on Okinawa Island, Japan.

First Complete Mitochondrial Genome of a Tanaidacean Crustacean ().

We present a complete mitochondrial genomic sequence for the tanaidacean (Richardson, 1899); this is the first complete mitogenome reported from the order Tanaidacea. The mitogenome is 13,988 bp long and contains 13 protein coding and two ribosomal RNA genes (as is typical for animal mitogenomes), and 21 of 22 transfer RNAs; we did not detect an isoleucine transfer RNA (trnI) gene. The gene order differed markedly from the hypothetical ground pattern for Pancrustacea; only four clusters (trnM + nad2; trnC + trnY + cox1 + trnL2 + cox2; trnD + atp8 + atp6 + cox3; trnH + nad4 + nad4l) ancestrally present were retained.

New replacement name for a homonym in Lepeophtheirus (Crustacea: Copepoda: Caligidae).

Markevich (1940) established Pseudolepeophtheirus Markevich, 1940 for Pseudolepeophtheirus longicauda Markevich, 1940 based on copepods collected from the pleuronectid fish Platichthys stellatus (Pallas, 1787). Dojiri Ho (2013) synonymized the genus and the species with Lepeophtheirus Nordmann, 1832 and Lepeophtheirus parvicruris Fraser, 1920, respectively. Later, Homma et al.

A new species of from the Bering Sea (Crustacea, Amphipoda, Pardaliscidae), with a redescription of .

A new pardaliscid amphipod, , is described from the Bering Sea at depths between 520 and 536 m, and Bruzelius, 1859 is redescribed based on specimens from Fredrikshald, Norway, near the species' type locality. Nucleotide sequences of mitochondrial cytochrome oxidase subunit I (COI) from the holotype and a paratype of are reported. While is similar to , it differs from the latter in having an asetose palp article 1 of maxilla 1, a gnathopod 1 coxa with a straight distal edge, and in the posterior margin of the basis of gnathopods 1 and 2, and pereopod 3, being heavily setose in females.

First in Situ Observations of Behavior in Deep-Sea Tanaidacean Crustaceans.

We report on the behavior of a deep-sea tanaidacean, sp. (Apseudomorpha: Gigantapseudidae), recorded at the depths of 6446-6447 m by the manned submersible . From recordings of at least three individuals walking on the sea floor, we confirm that sp.