Two new species of the bathyal holothurian genus Pannychia (Elasipodida, Laetmogonidae) from Japanese waters.

Sea cucumbers are one of the most common large animals in the deep-sea benthic communities, and those of the genus Pannychia are particularly abundant in the bathyal North Pacific Ocean. In Japanese waters, three species of Pannychia have been reported, mainly from the northern and eastern parts of the country. Here, we describe two new species from the western part of Japan. These two new species were placed in Pannychia by the presence of dorsal papillae on the ventrolateral radii and the presence of large wheel ossicles with rim teeth. They are distinguished from all other nominal species of Pannychia on the basis of the morphological characteristics of their body wheel ossicles. Pannychia nagasakimaruae sp. nov. has a unique ossicle composition in its dorsal and ventral body walls: four forms of wheel ossicles. Pannychia rinkaimaruae sp. nov. differs from other congeners in its small wheel ossicles in the dorsal and ventral body walls, which have conical rim teeth. We barcoded partial COI gene sequences from holotypes and paratypes of two new Japanese species. Our molecular phylogenetic analysis showed that these two new morphologically recognized Japanese species form distinct clades separated from other Pacific Pannychia species, so that the two new Japanese species were also supported by genetic results. In addition, we describe and visualize the poorly calcified calcareous rings of the two new species using X-ray µCT system, a useful method for observing such structures, which are important structures in holothurian anatomy.

The Abyssal Parasitic Flatworm Fecampia cf. abyssicola: New Records, Anatomy, and Molecular Phylogeny, with a Discussion on Its Systematic Position.

AbstractThe order Fecampiida, a group of parasitic turbellarians, has been poorly studied in terms of its species diversity, morphology, and ecology. Fecampiida is positioned within the monophyletic clade Adiaphanida, along with Tricladida and Prolecithophora, but their phylogenetic relationships are not well understood. Although the nervous and muscular systems of only two species in Fecampiida have been studied, recent research inferred morphological similarities between Fecampiida and Prolecithophora. In this study, we collected fecampiid cocoons and juveniles at depths of 1861-4438 m in Japanese waters. We identified the species on the basis of swimming juvenile specimens and by using histological and molecular methods, while we also examined its musculature and nervous system. Our study revealed a more complex nervous system than previously reported, with dorsal, lateral, and ventral pairs of longitudinal nerve cords connected through an anterior neuropile and posterior transverse commissures. While the nervous and muscular morphology suggested similarities with Prolecithophora, our phylogenetic analysis did not support a close relationship between Fecampiida and Prolecithophora.

Complete mitochondrial genome of a sea cucumber, Euapta godeffroyi (Echinodermata, Holothuroidea, Apodida, Synaptidae).

We determined the complete mitochondrial genome sequence of a holothurian Euapta godeffroyi belonging to the order Apodida. The complete mitogenome of E. godeffroyi was 16,410 bp in length and consisted of 13 protein-coding genes (PCGs), two ribosomal RNA genes, and 22 transfer RNA genes. The orders of PCGs and rRNAs did not match those of any recorded holothurian mitogenomes. The maximum likelihood (ML) phylogenetic tree placed E. godeffroyi as the sister group to chiridotid species and supported the monophyly of the order Apodida.

Four new dendrochirotid holothurians collected from the Seto Inland Sea and the western part of the Sea of Japan, western Japan.

Fifteen dendrochirotid holothurians, including four new species, were collected from the Seto Inland Sea and the western part of the Sea of Japan, western Japan by the training and research vessel (TR/V) TOYOSHIO MARU of Hiroshima University, during the 201415 surveys. Massinium toyoshiomaruae sp. nov., Thyone kyushuensis sp. nov., T. liaoi sp. nov., and T. toyoshiomaruae sp. nov. are described as new species. Massinium toyoshiomaruae sp. nov. is readily distinguishable from all congeners by the absence of bodywall ossicles and the presence of table ossicles in the tentacle base. Thyone kyushuensis sp. nov. possesses large polyporous-tables in the introvert and tentacles, bodywall ossicles of a peculiar shape, and tentacle ossicles comprised mostly of unbranching rods and/or rod-like rosettes, which differ from those of all congeners. Thyone liaoi sp. nov. resembles T. pedata Semper, 1867 in its bodywall ossicles, however, it is distinguishable by the absences of huge ossicles in the body wall and the needle-shaped ossicles in the gonadal tubules. Thyone toyoshiomaruae sp. nov. is distinguishable from all other Thyone by the presence of the peculiar shape of the bodywall ossicles. Partial sequences of the mitochondrial cytochrome c oxidase subunit I gene are provided from the type specimens of the new species as DNA barcoding data.

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, Flabelligena hakuhoae sp. 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 species of the rare, deep-sea polychaete genus Benthoscolex from the Sea of Kumano, Japan (Annelida, Amphinomidae).

A new species of amphinomid polychaete, Benthoscolex seisuiaesp. 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.

A taxonomic revision of the genus Apostichopus (Holothuroidea: Stichopodidae) from Japan.

Complete redescriptions of sea cucumbers in the genus Apostichopus Liao, 1980 are provided using the type specimens and specimens deposited in the National Museum of Nature and Science, Tsukuba, Japan. The genus consists of A. armatus (Selenka, 1867) and A. japonicus (Selenka, 1867), which can be distinguished by some spicules in the dorsal body wall; the rim of reduced table spicules in A. armatus is spinous, while that in A. japonicus is smooth. Spicules from the tentacles, papillae, tube feet, and cloaca are similar for both species.

Recurrent hemarthrosis after unicompartmental knee arthroplasty.

Recurrent hemarthrosis after knee arthroplasty can be disabling, requiring adequate and immediate diagnosis and treatment for recovery of symptoms and joint function. The most commonly reported cause is impingement of proliferative synovium between prosthetic components. Although various procedures for hemarthrosis have been reported after knee arthroplasty for patients who do not respond to conservative treatment, the recommended first-line therapy is open surgery or embolization. Although hyperplastic synovium was observed during the first and second arthrotomy, in our case, tissue impingement was not detected. We describe a rare case of recurrent hemarthrosis after unicompartmental knee arthroplasty (UKA) and successful treatment by open synovectomy. A 66-year-old woman presented with spontaneous osteonecrosis of the medial femoral condyle in the right leg. She underwent UKA of the right knee of the medial condyle. Eighteen months after UKA, the patient developed recurrent hemarthrosis. Open arthrotomy was performed 22 months after UKA, revealing only hematoma with no obvious hemorrhage or loosening of the prosthesis. No history of trauma or use of anticoagulant medications was present. After a symptom-free period of 8 months, another 2 episodes of hemarthrosis occurred over the course of 8 months. A second open arthrotomy was performed. Hyperplastic synovium with fibrin and hemosiderin pigmentation was observed, again without hemorrhage or loosening. There were no pathological features of pigmented villonodular synovitis. Synovectomy was performed, and no hemarthrosis has recurred for 2 years.