Four alien monogeneans, Unilatus unilatus Mizelle and Kritsky, 1967, U. brittani Mizelle, Kritsky, and Crane, 1968, Trinigyrus peregrinus n. sp., and Heteropriapulus heterotylus (Jogunoori, Kritsky, and Venkatanarasaiah, 2004), were collected from the gills of vermiculated sailfin catfish, Pterygoplichthys disjunctivus (Weber, 1991) (Siluriformes: Loricariidae), in inland waters of Okinawa-jima island, Okinawa Prefecture, Japan. Unilatus unilatus and U. brittani represent new country records for Japan. Trinigyrus peregrinus n. sp. is characterized by a coiled male copulatory organ that forms a circle and does not articulate with its accessory piece. Heteropriapulus heterotylus was newly collected from two rivers in south-central Okinawa-jima island. These monogeneans are all considered to be native to South America and to have been co-introduced with the host fish into the inland waters of the island by release of ornamental pet fish.
The freshwater heteronemertean Apatronemertes albimaculosa Wilfert and Gibson, 1974 has previously been reported from Germany, Austria, and the USA. All these records were from aquarium tanks with commercially distributed tropical and/or subtropical water plants; by hiding among their roots, the worms are thought to have been introduced from an unidentified place of origin. We report the occurrence of A. albimaculosa for the first time from Japan, based on specimens found in private home aquaria for guppy breeding, with a total of 18 species of water plants grown for different periods and lengths of time but not all at the same time. Histological examination confirmed the presence of diagnostic features of this species, including a complex precerebral vascular system and hermaphroditism. The partial sequence of the mitochondrial cytochrome c oxidase subunit I gene (607 bp) of the Japanese material is identical with that of a heteronemertean specimen from a freshwater tank in Madrid, Spain, which had been deposited in the public databases but left unidentified as to its species, genus, or family. Apatronemertes albimaculosa appears unlikely to be able to survive below 10°C for more than about a week, which suggests that its native locality is in the tropics or subtropics, not the temperate zone. The barcoding sequence herein determined will serve in future studies to help locate the natural place of origin.
Ehlersileanira andamanensis n. sp. is described from southwestern Thailand in the Andaman Sea, based on specimens collected during the Thai-Danish BIOSHELF Project in 1996–2000. The new species differs from E. incisa (Grube, 1877) by having auricles and ctenidia on the ceratophore of the median antenna and dorsal tubercles on segment 3, whereas in the latter species the ceratophore of the median antenna only has auricles and there are no dorsal tubercles on segment 3.
A species of marine limnodriloidine oligochaete, Thalassodrilides cf. briani Erséus, 1992, is recorded from gravelly sand sediments of the subtidal zone in Ehime Prefecture, Japan. The present material agrees with the original description of T. briani, which was first found at Hong Kong, with the exception that the copulatory sacs are oval; not slender. Despite the lack of genetic data for the Hong Kong population, we conclude that the Japanese specimens are conspecific with it, or at least very closely related, based on morphological considerations. This is the first record of the genus Thalassodrilides Brinkhurst and Baker, 1979 in Japan. The phylogenetic relationships between T. cf. briani and three other species of Thalassodrilides are estimated, based on partial DNA sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene and the complete nuclear ribosomal Internal Transcribed Spacer (ITS) region, using two members of the closely related genus Doliodrilus Erséus, 1984 as outgroups. The genetic analysis shows that T. cf. briani is a species delimited by both mitochondrial and nuclear data, and clearly separated from at least its closely related congeners in the Northwest Atlantic (Caribbean and adjacent areas).
The terrestrial hirudinid leech Poecilobdella nanjingensis Yang, 1996 is reported for the first time from Taiwan, having previously been found only in continental China. A morphological description of the new material from Taiwan is provided here, confirming that, contrary to the diagnosis of Poecilobdella Blanchard, 1893, P. nanjingensis lacks a vaginal caecum in its female reproductive system. In addition, molecular phylogenetic analyses reveal that P. nanjingensis is part of a clade consisting of the hirudinid genera defined by the lack of a vaginal caecum. These results highlight the need for further taxonomic studies on the generic position of this species.
A rare copepod parasitic on marine fish, Luetkenia elongata Shiino, 1963 (Siphonostomatoida: Pandaridae), is redescribed based on type specimens and additional specimens obtained from Luvarus imperialis Rafinesque, 1810 caught in the eastern and western North Pacific Ocean off California and Japan, respectively. This represents the first record of this parasite from Japanese waters. The copepod differs from its sole congener, L. asterodermi Claus, 1864, by following features of the female: fourth pedigerous somite with one pair of elongate posterolateral lobes; genital complex bearing a pair of well-developed posterolateral lobes with one conical protuberance on lateral corner; abdomen clearly longer than wide; and caudal rami more than 2.0 times longer than wide.
A new genus and species of talitrid amphipod, Lowryella wadai, is described from estuarine reed marshes facing the Bungo Channel, western Japan. This genus belongs to the 4-dentate, cuspidactylate group of talitrids and is characterized by having: (1) a short and slender antenna 2, (2) a mediodistally lobate article 2 and reduced article 4 of the maxillipedal palp, (3) a deeply subchelate gnathopod 1 in both sexes, (4) a bulge on the basis and ischium of female gnathopod 1, (5) a marginally bare outer ramus of uropod 1, and (6) a telson lobe armed only with apical robust setae. Several genera including palustral talitrids display features in common with this new genus, but the character combination shown above distinctly separates Lowryella from them. Lowryella is the first stenotopic representative of the Talitridae from estuarine marshes in Japan.
A platycephalid fish, Onigocia grandisquama (Regan, 1908) is rediagnosed based on 52 specimens, including the holotype, from the Indo-West Pacific. Geographic variation in the species was recognized in the number of pectoral-fin rays, the first example of such variation in fin ray counts in the Platycephalidae. The species displays wide intraspecific variation in the numbers of lachrymal, preocular, suborbital, and pterotic spines, with values for the first two overlapping with those of the very similar Onigocia spinosa (Temminck and Schlegel, 1843), making it difficult to separate the two. Onigocia grandisquama can be distinguished from O. spinosa, as well as from Onigociamacrocephala (Weber, 1913) and Onigocia macrolepis (Bleeker, 1854), which share with O. grandisquama an ocular flap on the posterior part of the eye, in lacking spines on the inner, middle, and/or outer ridges of the lachrymal. The generally greater number of pterotic spines also helps to separate O. grandisquama from its three congeners.
Eight specimens of Chelidoperca maculicauda Bineesh and Akhilesh, 2013 from the Gulf of Aden and five of C. occipitalis Kotthaus, 1973 from the Gulf of Oman represent the first records of those species from the respective localities, and suggest a wide distribution of both along the Arabian Sea coast. Chelidoperca maculicauda was previously recorded only from its type locality on the southwest coast of India, and C. occipitalis, only from the west coast of India, Pakistan, and Socotra Island (Yemen; type locality), western Arabian Sea. The two are compared with all currently known congeners and their diagnostic characters are reviewed.
Three specimens (31.6–38.2 mm standard length) of Cypho zaps Gill, 2004 (Pseudochromidae), previously known from voucher specimens only from Indonesia, the Philippines, and southern Taiwan, were collected off Yonaguni-jima island, Yaeyama Islands, southern Ryukyu Islands. They were clearly distinguished from the only known other congener, C. purpurascens (De Vis, 1884), by the staggered arrangement of the dark vertical lines in the center of each body scale, which do not form continuous bars as they do in the latter species. These specimens represent the first records of C. zaps from Japan supported by voucher specimens, and the northernmost distributional records of the species.
A deepwater cardinalfish, Hynnodus megalops Smith and Radcliffe in Radcliffe, 1912, originally described from four specimens from the Philippines, is redescribed as a valid species of Epigonus. Epigonus megalops is similar to E. atherinoides (Gilbert, 1905) but differs in having a relatively longer head and upper jaw, a relatively deeper caudal peduncle, and ctenoid scales on the lateral sides of the body. Epigonus atherinoides is redescribed based on the holotype, previously known specimens, and newly collected ones from the Society Islands and Western Australia. Additionally, two specimens of E. draco Okamoto, 2015 collected from the Society Islands represent the first record of this species from the central South Pacific.
Parapercis bicoloripes Prokofiev, 2010, previously known only from waters off Vietnam, is recorded from the northern Gulf of Thailand, the east coast of the Malay Peninsula, northern Borneo, and Panay, Philippines. Detailed examination of 27specimens (66.1–136.0 mm standard length) revealed significant growth-related changes in several body proportions and coloration. In addition, 11 specimens (44.2–74.1 mm standard length) of Parapercis diplospilus Gomon, 1981, previously recorded from Vietnam, the Philippines, Indonesia, Papua New Guinea, and Australia, are reported for the first time from the Gulf of Thailand and off Terengganu State, Malaysia, east coast of the Malay Peninsula.