First Record of the Deep-Sea Sea Spider (Arthropoda: Pycnogonida) from the Northwestern Pacific, with a Note on an Attached Crinoid.

We report the first record of the pallenopsid pycnogonid species (Schimkewitsch, 1893) from the northwestern Pacific. Based on one male specimen collected from 1987-2007 m depth off the southeastern coast of Hokkaido, Japan, we redescribe the species and present its cytochrome oxidase subunit I (COI) sequence for use in future DNA barcoding. We found a cystidean-stage crinoid on the leg-1 femur of the sea spider, representing the first record of a cystidean found on a sea spider.

Zooid arrangement and colony growth in Porpita porpita.

Background: The blue button, Porpita porpita (Porpitidae), is a highly integrated colonial animal-i.e., a superorganism.

Microfocus X-Ray Computed Tomography of (Platyhelminthes: Polycladida) with an Evaluation of Histological Sections After Scanning.

Microfocus X-ray computed tomography (micro-CT) is expected to be utilized in the taxonomy of macroturbellarians that require histological technique(s) for identification, allowing nondestructive observation of the internal structures of specimens in a short time. With micro-CT, we observed a polyclad flatworm, (Schmarda, 1859), in this study. In the CT images, the main reproductive organs in the polyclad specimen were well observed, but some diagnostic characters were unclear or undetectable.

Physalia gonodendra are not yet sexually mature when released.

The blue bottle genus Physalia is one of the well-known siphonophore belonging to the Cnidaria, Hydrozoa. Physalia is also known as a ferocious predator, occasionally stinging and fatally wounding humans, but key details of its life cycle and reproductive biology are unclear. Physalia have separate sexes, and sexual reproduction occurs through the release of complex structures called gonodendra that contain many gonophores that will release either eggs or sperm.

Differences of Sucker Formation Processes Depending on Benthic or Pelagic Posthatching Lifestyles in Two Octopus Species.

AbstractMorphologies of animal appendages are highly diversified depending on animal lifestyles. In cephalopods (Mollusca, Cephalopoda), an individual possesses multiple arms that contribute to elaborate behaviors, and suckers on them enable various arm functions. In octopus hatchlings, arm and sucker morphologies can be divided into two different types due to alternative posthatching lifestyles, that is, pelagic or benthic lifestyles, although the underlying developmental differences have yet to be elucidated.

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.

Metarhachotropis parva, a new genus and species of Eusiridae (Crustacea: Amphipoda) from Sagami Bay, central Japan.

The monotypic genus Metarhachotropis (Crustacea: Amphipoda: Eusiridae) is erected with M. parva sp. nov.

Exploring the trends of adaptation and evolution of sclerites with regards to habitat depth in sea pens.

Octocorals possess sclerites, small elements comprised of calcium carbonate (CaCO) that are important diagnostic characters in octocoral taxonomy. Among octocorals, sea pens comprise a unique order (Pennatulacea) that live in a wide range of depths. Habitat depth is considered to be important in the diversification of octocoral species, but a lack of information on sea pens has limited studies on their adaptation and evolution across depth.

Partial redescriptions of three holothurians with hook papillae (Apodida: Chiridotidae): Taeniogyrus japonicus (Marenzeller, 1882), T. dendyi (Mortensen, 1925), Scoliorhapis theelii (Heding, 1928).

New specimens of Taeniogyrus japonicus (Marenzeller) were collected from Iwami coast and Sado island of the Sea of Japan. According to detailed observations of external and internal organs, we transferred T. japonicus, T.

Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda).

Three new species of the amphipod family Aoridae Stebbing, 1899 were collected from the bottom of a 40400 m depth in Sagami Bay, central Japan. Aora biarticulata sp. nov.

Hydrocoel morphogenesis forming the pentaradial body plan in a sea cucumber, Apostichopus japonicus.

Echinoderms constitute an animal phylum characterized by the pentaradial body plan. During the development from bilateral larvae to pentaradial adults, the formation of the multiple of five hydrocoel lobes, i.e.

n. sp., a New Species of Copepod (Cyclopoida: Splanchnotrophidae) Parasitic on the Chromodoridid Nudibranch Baba, 1988 Off the Oki Islands, Japan, with Microanatomical Observation Using Micro-CT.

A new species of the family Splanchnotrophidae Norman and Scott, 1906 (Cyclopoida) is described based on both sexes collected from off the Oki Islands, the Sea of Japan. Specimens of both sexes of n. sp.

Lineid Heteronemerteans (Nemertea: Pilidiophora) from Sagami Bay, Japan, with Some Proposals for the Family-Level Classification System.

We performed molecular phylogenetic analyses using nucleotide sequence data from five genes (16S rRNA, cytochrome oxidase subunit I, 18S rRNA, 28S rRNA, histone H3) determined from 36 specimens representing 25 (10 named, 15 unnamed) species of lineid heteronemerteans collected in Sagami Bay, Japan, along with other sequences obtained from public databases. External features of the 25 species are briefly described and illustrated. Takakura, 1898 is transferred to Huschke, 1830.

Description of a New Species of the Marine Flatworm (Platyhelminthes: Polycladida) and its Three Known Congeners from Misaki, Japan, with Inference of Their Phylogenetic Positions within Prosthiostomidae.

The present study provides morphological descriptions of four species of (Polycladida, Prosthiostomidae)- Kato, 1937; sp. n.; cf.

Sucker formation in a bigfin reef squid: Comparison between arms and tentacles.

Cephalopods have acquired numerous novelties and expanded their habitats to various marine environments as highly agile predators. Among cephalopod novelties, multiple arms are used for complex behaviors, including prey capture. Suckers on arms are innovative features for realizing these arm functions.

Description of a New Brooding Species of (Echinodermata: Ophiuroidea) from Japan.

A new species of brittle star, , is described from two specimens collected in Sagami Bay, central-eastern Japan. Photographic examination of the holotype specimen of the sole other congener, Koehler, 1930, indicates that sp. nov.

Developmental Process of a Heterozooid: Avicularium Formation in a Bryozoan, .

In bryozoans (phylum Bryozoa), representative colonial animals mostly found in marine environments, some species possess different types of individuals (heterozooids) specialized in different functions such as defense or structural support for their colonies. Among them, the best-known heterozooids are the avicularia, known to function as defenders. The differentiation processes of heterozooids, including avicularia, should be important keys to understand the evolutionary significance of bryozoans.

Two new deep-sea species of the genus Henricia (Asteroidea: Spinulosida: Echinasteridae) from Japanese waters.

Two new deep-sea Henricia species, Henricia margarethae n. sp. and Henricia fragilis n.

Morphogenesis and histogenesis during the arm regeneration in a basket star Astrocladus dofleini (Euryalida, Ophiuroidea, Echinodermata).

Basket stars, that is, Ophiuroidea in Echinodermata, exhibit distinctive morphological characteristics with their complicatedly branched arms that can regenerate immediately after mutilation. Although, in brittle stars, that is, ophiuroids with nonbranched arms, the arm regeneration process following accidental trauma or autotomy have been morphologically and histologically observed in several species, few studies have so far been carried out on the regeneration of branched arms in basket stars. In this study, the developmental and morphological features of arm regeneration in Astrocladus dofleini (Gorgonocephalidae, Euryalida, Euryophiurida), one of the most common basket star species in Japanese waters, was anatomically and histologically investigated.

A taxonomic review of the genus (Echinodermata, Ophiuroidea, Euryalida, Gorgonocephalidae) from Japanese coastal waters.

Japanese species of the genus (Echinodermata, Ophiuroidea, Euryalida, Gorgonocephalidae) are reviewed. recently has two junior synonyms, Döderlein and Döderlein, however, status of these species has long been questioned. These species concepts have not been reviewed in recent years and no molecular phylogenetic analyses have been performed.