During 14 to 17 November 2016, the joint event of the 22nd International Congress of Zoology and the 87th meeting of Zoological Society of Japan was held in Okinawa prefecture. As one symposium of it on 17 November 2016, the Japanese Society of Systematic Zoology Symposium 2016 entitled ‘Taxonomical studies reveal marine biodiversity of Okinawa’ was conducted at Okinawa Convention Center (Ginowan City, Okinawa). The four interesting lectures were given by the special invited speakers: Masato Hirose ‘Bryozoan diversity in Okinawa―species diversity and unique life forms associated with various bottom environments―’, Yuna Zayasu ‘Research activities by Japanese Society for Coral Taxonomy’, Hirofumi Kubo ‘The problem on the conservation of the molluscan diversity in bay area in Okinawa-jima Island’, and Tetsuo Yoshino ‘Coastal fish fauna of the Ryukyu Islands and its zoogeography’.
Bryozoans are sessile, clonal animals; about 6,000 living species have been described. The recent study revealed approximately 1,000 species including undescribed species in Japanese waters. Diversity of bryozoans in Okinawa has been not studied in detail; only 22 species have been reported previously. The recent review of bryozoan diversity in the Nansei Islands including Okinawa estimates more than 150 species in this area; the fauna is characterized with both temperate and the Indo-Pacific species. Marine benthic environment in Okinawa varies in the characters, such as dead coral and rubble assemblage in shallow depth, sandy or muddy bottom in deeper area, and mangrove forest at estuarine area. Depends on the diverse benthic environment, bryozoans form colonies of various morphologies on different kinds of substrates such as dead coral and shells. Some bryozoans inhabit muddy bottom by forming erect or free-living colonies. Recent study on bryozoan life-history find the correlation between sand-dwelling bryozoan life-history and climatic characters such as high temperature during summer and disturbance of the water column caused by typhoon. Furthermore, specific relationships between endemic bryozoan species and other organisms in Okinawa also contribute to maintain the high diversity of benthic organisms in Okinawa. Bryozoans are suitable for further study on biogeography and speciation of marine benthic organisms, since some bryozoan species have lower dispersal ability and their distribution is limited in the small area. Taxonomic studies of highly diverse marine organisms in Okinawa have a potential to provide crucial information for development of ecological studies and protection of the organisms and their habitat in Okinawa.
When you try to identify zooxanthellate scleractinian corals, you are faced with two general types of problems. One is the difficulty of coral identification. The other is the ongoing revision of coral taxonomy. A group of scleractinian coral identifiers in Japan, i.e., the ‘Japanese Society for Coral Taxonomy’, has been trying to resolve these problems. We will introduce our efforts and approaches here.
Approximately half of the threatened Japanese tidal-flat molluscan species live in Nansei-shoto Islets, and 84% of them (71 species) distribute in Okinawa-jima Island. Twenty-four out of 71 species are endemic or limited to Okinawa-jima. Therefore, Okinawa-jima is one of the most important habitats in Nansei-shoto for those molluscs. A vast tidal flat with an area of 1,962 ha used to exist in Okinawa-jima in 1945. However, 75% of the area has been lost by 2012 due to reclamation. After endangered species in Okinawa-jima was evaluated quantitatively, all 24 species were considered the critically endangered species. As for the tidal-flat molluscs of southern part of Okinawa-jima Island, species diversity was already decreased by coastal development for economic activities. The first extinct species of Japanese tidal-flat molluscs was recognized in Okinawa-jima Island. Natural bay areas still remain in Oura bay and Haneji naikai inland sea, northern part of Okinawa-jima. We must protect these bay areas where the threatened tidal-flat molluscs are able to inhabit.
More than 1,300 species of fishes have been reported from the Japanese side of the Sea of Japan. However, occurrence records for a great number of these species are not documented by voucher specimens, rendering estimates of the diversity of fishes from this region unclear as to their reliability. Given this situation, ichthyologists at the Maizuru Fisheries Research Station of Kyoto University are central to a research group aiming to provide a more reliable estimate of the diversity of the fish fauna of this region that is based on a reproducible data such as voucher specimens. Here we provide some biogeographic (24 species) and taxonomic (2 species) notes as a preliminary report towards this goal. As a result of new biogeographical findings, 10 species are confirmed from this region for the first time, and the distributional ranges of 14 other species are extended to the east. Most of these 24 species are not residents in the Sea of Japan, rather they are migratory species likely to have drifted from the southward via the Tsushima Warm Current. An unidentified congrid species, Ariosoma sp. and an undescribed cynoglossid species, Symphurus sp., were collected off Kyoto Prefecture. Exact identification of the former species, and a description and formal naming for the latter species, will be the subject of studies conducted in the near future.
Five specimens (306.5–402.6 mm of total length) of the ophichthid eel, Pisodonophis sangjuensis Ji and Kim, 2011 (Actinopterygii: Anguilliformes), were collected from off Kagoshima Prefecture, Japanese waters of the East China Sea, during 2013–2014. They represent the first records of the species from Japanese waters, and the new standard Japanese name “Fuchinashi-umihebi” is proposed for the species. Although arrangements of vomerine teeth of the present specimens differ from those of an illustration of the holotype given in the original description, it is inferred as an ontogenetic difference. Pisodonophis sangjuensis is similar to P. cancrivorus (Richardson, 1848) in having the dorsal-fin origin positioned a vertical through the middle of the pectoral fin, the presence of three preopercular pores, a dark margin on the cephalic sensory pores, and about 150 total vertebrae. However, the former can be distinguished from the latter by the upper-jaw length (27–32% of head length vs. 36–38% in the latter), the shape of snout (robust and blunt vs. sharp and pointed tip), the shape of teeth (conical with pointed tip vs. granular), coloration of its dorsal and anal fins (pale white, except for short posteriormost areas vs. dark brown to dark grayish margin), and the number of total vertebrae (143–153 vs. 153–164).
A specimen of the tilefsh, Hoplolatilus fourmanoiri Smith, 1964 was collected from off Amitori Bay, Iriomote Island, Yaeyama Islands of the Ryukyu Islands, Japan. It represents the northernmost record for the species and the first record of the species from Japan. Hoplolatilus fourmanoiri can be distinguished from its congeners by the following combination of characters: caudal fin not forked; pointed spines located at corner of the preopercle and the mid-posterior margin of the opercle; maxillary broad, its maximum depth almost equal to diameter of pupil; ctenii of scales prominent; a large dark blotch located at posterior tail to caudal fin; a yellow band running from head to shoulder. The present specimen has a slightly deeper head (69.7% of head length vs. 62–68%) and more scales below lateral line (42 vs. 34–41) than other specimens, but these differences are insignificant. The dark posterior blotch of the present specimen is paler and more yellowish than the previous report, however the body coloration of the Japanese specimen is paler, which we feel is due to the condition of the specimen. The shape of the caudal fin of H. fourmanoiri was formerly described as truncate with dorsal produced. We described it as shallow double truncate. A new standard Japanese name “Hotarubi-sango-amadai” is proposed for the species.