Seven specimens of Dictyosoma tongyeongensis Ji and Kim, 2012, collected from Notojima, Ishikawa, Japan, are described in detail and a revised species diagnosis is proposed. Morphological comparisons and sequence data from the mitochondrial DNA cytochrome c oxidase subunit I gene support the conspecificity of Japanese and Korean specimens, but suggest that the congener D. burgeri van der Hoeven, 1855 as currently recognized may include two separate species.

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A single adult specimen of Pomadasys kaakan (Cuvier in Cuvier and Valenciennes, 1830), 483.0mm in standard length, was collected at a depth of 36m off the Satsuma Peninsula, Kagoshima Prefecture, Japan. Because previous records of the species from Japan had been based on mis-identifications of P. argenteus (Forsskal, 1775), the Kagoshima specimen represents the first reliable record of P. kaakan from Japan supported by a voucher specimen.

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A new epigonid fish, Epigonus draco n. sp., is described on the basis of six specimens (88.8-160.1 mm in standard length: SL) collected from the Philippines, Solomon Islands, and Vanuatu in the Western Pacific. This species belongs to a subgroup of Epigonus, known as the "Epigonus constanciae group," whose members have a pungent opercular spine, more than 40 pored lateral-line scales (47-49 to the end of the hypural+3-4 on the caudal fin), and VII-I, 10 dorsal-fin rays. The new species is distinguished from other congeners of the group in having the following combination of characters: absence of a maxillary mustache-like process, absence of ribs on the last abdominal vertebra, total gill rakers 22-23; pyloric caeca 7-9; pectoral-fin rays 19-20; scales below lateral line 9; vertebrae 10+15; uppermost margin of pectoral-fin base lower than horizontal line through center of eye; proximal radial of first anal-fin pterygiophore slender; and mouth cavity black. In addition, Epigonus chilensis Okamoto, 2012 is rediagnosed based on specimens from near its type locality.

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The validity of the platycephalid species Platycephalus clavulatus Cantor, 1849, described from a single specimen collected in the sea of Pinang (=Penang), Malaysia, is evaluated. Although it has been suggested that the holotype of the species is a specimen registered as BMNH 1860.3.19.270 in the Natural History Museum, London (BMNH), which is identifiable as Cociella punctata (Cuvier, 1829), the total length (TL) of the holotype reported by Cantor is 5 7/8 inches (=149 mm), significantly longer than the damaged BMNH specimen, which is estimated to have had a TL of 121 mm. According to the original description of P. clavulatus, the holotype has 11 second dorsal and anal fin rays, one preorbital spine, and two suborbital spines, values which agree with those of C. punctata, a species widely distributed in the western Pacific and the Indian Ocean, including Penang. Although these characters are also present in Cociella crocodila (Cuvier, 1829), that species is known only from Japan, Korea, China, and Taiwan. We conclude that P. clavulatus is conspecific with C. punctata and is a junior synonym of that species.

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A single specimen of the midwater grenadier Odontomacrurus murrayi Norman, 1939 was collected from off the Pacific coast of Miyagi Prefecture, Tohoku region, northern Japan, at a depth of 168-204 m (bottom depth 2641 m). It represents the first record of O. murrayi from Japanese waters and the northernmost record of this species in the Pacific. Previous records of O. murrayi are summarized and collection data for these records suggest that the species is generally confined to the mesopelagic layer of the open ocean. New Japanese names "Kurobouzudara-zoku" and "Kurobouzudara" are proposed for Odontomacrurus and O. murrayi respectively.

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A new phyllophorid sea cucumber, Thyone susamiensis sp. nov., is described from the intertidal zone of the south coast of Wakayama Prefecture, western Japan. It is distinguished from the most of its congeners by the absence of ossicles in the body wall. Thyone susamiensis has only rosette-like ossicles in the introvert, where table-like ossicles are usually observed in other Thyone species. The usual table-like ossicles were observed only in the peri-oral skin in T. susamiensis. Among congeners, this condition has been reported only in Thyone flindersi O'Loughlin, Barmos, and VandenSpiegel, 2012. However, T. flindersi occasionally has table-like ossicles in the anal appendages, where T. susamiensis usually only has rod-like ossicles. The general body colouration and the shape of the calcareous ring are also distinctive, separating species T. susamiensis from T. discolor Sluiter, 1901, T. roscovita Herouard, 1889, and T. venusta Selenka, 1867, species for which detailed description of ossicles are lacking.

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A new genus and species of clausiid copepod (Cyclopoida), Oshoroclausia shibazakii n. g. n. sp., is described based on a single female collected subtidally in Oshoro Bay, on the western coast of Hokkaido, the Sea of Japan. Oshoroclausia is characterized by the following feature of female: elongate body lacking distinct segmentation from first pedigerous to the anal somite, 2-segmented antenna with two terminal claws, and legs 1 to 4 bearing 2-segmented rami. This is the first record of a clausiid copepod from Japanese waters.

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Lernaeascus kabuto sp. nov. (Cyclopoida: Philichthyidae) is described based on specimens of both sexes collected from two species of angelfish (Actinopterygii: Pomacanthidae), the purplemask angelfish Centropyge venusta (Yasuda and Tominaga, 1969) and the yellow angelfish C. heraldi Woods and Schultz, 1953, caught in the East China Sea near Kumejima Island, Japan. Lernaeascus kabuto sp. nov. is easily distinguished from its congener, L. nematoxys Claus, 1886, by the following characters: the male has a pair of elongate, distomedially notched dorsal plates on the second pedigerous somite, four abdominal somites, a pair of dorsal hamuli on the third abdominal somite, a non-bifurcate genital operculum, a curved proximal antennulary segment, a naked maxillule, a maxilla without a posteriorly-directed process on the syncoxa, and the endopod of leg 1 modified into a simple spine; and the female has a triangular antenna, a styliform process on the labrum, and three setae on the exopods of legs 1 and 2.

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Three species of calanoid copepods belonging to the genus Acartiella Sewell, 1914 are redescribed from three estuaries in Thailand. Two species, Acartiella kempi Sewell, 1914 and A. nicolae Dussart, 1985, were collected from the Kraburi Estuary and Prasae Estuary, respectively, representing the first records of these species from Thailand. In addition, A. sinensis Shen and Lee, 1963, collected from the Bangpakong Estuary on the northeast coast of the Gulf of Thailand, is redescribed, as the original description is poor. This genus is zoogeographically unique as it is restricted to tropical and subtropical Asian estuarine waters, and this study increases our understanding of the evolution of estuarine copepods in the Indo-West Pacific.

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The four-plated barnacle Tesseropora alba Ren and Liu, 1979 is recorded for the first time away from its type locality in the Xisha Islands, South China Sea. The new localities are northwestern Taiwan and Okinawa. The species is redescribed in detail, with a discussion of its likely geographical range in the Pacific.

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Cystacanths and acanthellae of the illiosentid acanthocephalan Pseudorhadinorhynchus samegaiensis Nakajima and Egusa, 1975 are described from the anisogammarid amphipod Jesogammarus (Annanogammarus) fluvialis Morino, 1985 in a stream at the Samegai Trout Experimental Station, the type locality of the acanthocephalan, in the Lake Biwa basin, Shiga Prefecture, west-central Japan. This amphipod is herein regarded as an intermediate host of P. samegaiensis. This is the first description of developmental stages of any member of the genus Pseudorhadinorhynchus Achmerov and Dombrovskaja-Achmerova, 1941. Since J. (A.) fluvialis does not occur in the Lake Biwa proper but two other congeners, J. (A.) annandalei (Tattersall, 1922) and J. (A.) naritai Morino, 1985, inhabit the lake, it is suggested that P. samegaiensis uses one or both of the latter two amphipods as its intermediate host(s) in the lake.

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We collected a specimen of Exocoelactis actinostoloides (Wassilieff, 1908) from the type locality of the species in October, 2012. The name of Ex. actinostoloides has been misapplied to a species of Entacmaea (Ehrenberg, 1834) around the Indo-Pacific region in many works, including scientific reports, although some authors have noted the error. A true specimen of Ex. actinostoloides has not been found in Japanese waters since the collection of the type specimen at Jogashima, Kanagawa Prefecture, in 1904. Here, we redescribe Ex. actinostoloides based on the present specimen from the opposite side of the Uraga Strait, and analyze the phylogenetic position of this species within Actiniaria based on mitochondrial 12S and 16S rDNA sequence data. These are the first molecular data ever provided for the family Exocoelactinidae. The sequence data indicate that Ex. actinostoloides is a member of the superfamily Actinostoloidea, and that it is most closely related to the family Actinostolidae.

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