Ko Tomikawa

Hiroshima University | HU · Graduate School of Education

The Shiretoko Peninsula, located at the southernmost point of the Sea of Okhotsk, was registered as a World Natural Heritage in 2005 in recognition of its rich biodiversity and an example of the interaction between marine and terrestrial ecosystems. However, there is insufficient information on its marine biota, which is an essential component of t...

This study describes Gnorimosphaeroma rivulare sp. nov. from a stream on Chichi-jima Island, Ogasawara Islands, Japan. This is the second freshwater species of Gnorimosphaeroma and the third Sphaeromatidae from oceanic islands. Gnorimosphaeroma rivulare sp. nov. is morphologically similar to G. boninense Nunomura, 2006, G. naktongense Kwon & Kim, 1...

A new species of pseudocrangonyctid amphipod, Pseudocrangonyx asuwaensis, is described from subterranean water in a quarry on Mt. Asuwa "Nanatsuo-guchi", Fukui Prefecture, Japan. Pseudocrangonyx asuwaensis sp. nov. differs from its congeners in various morphological features, such as head without eyes, relative length of antennae 1, female antenna...

In recent years, the impact of rising water temperatures associated with global warming on cold-water freshwater organisms has become a major issue, and understanding the physiological and ecological elements that support temperature limits is essential for the conservation biology of freshwater organisms. We describe a new species of thermophilic...

Symbiosis includes commensalism, mutualism, and parasitism, however in many symbiotic relationships, it is di cult to determine which type they are in. Since trophic-linkage is a necessary factor to determine this, data on feeding ecology of symbionts is essential to understand symbiont-host relationships. Amphipods of the genus Dactylopleustes are...

A new podocerid amphipod, Podocerus setouchiensis sp. nov. , is described from the Etajima Island, the Seto Inland Sea, Japan. This new species differs from its congeners by the dorsal carination of pereonites and pleonites, and form of the antenna 1, gnathopods 1 and 2, uropods 1 and 2, and telson. Nucleotide sequence data of the mitochondrial cyt...

Amphipod crustaceans are a major group of invertebrates that predominantly occur in groundwater ecosystems. Eoniphargus is a mesogammarid genus with only two known species from the groundwater systems of the Japanese archipelago and Korean Peninsula. However, there is a dearth of taxonomic studies on this genus, and the species diversity within Eon...

The subterranean amphipod genus Pseudocrangonyx is diverse in Far East Asia, including the Japanese Archipelago. However, Pseudocrangonyx species have not been recorded from the Ryukyu Islands, which extend southwest of the Japanese Archipelago. This study describes a new species of Pseudocrangonyx, Pseudocrangonyx dunan sp. nov., from Yonaguni Isl...

We describe a new tryphosid amphipod, Paronesimoides calceolus sp. nov., from the Shinkai Seep Field, Mariana Trench, at a depth of 5689–5683 m. This is the first species of Paronesimoides to be described in the Mariana Trench and the deepest record of the genus. Paronesimoides calceolus sp. nov. differs from its congeners in characteristics of its...

The amphipod genus Melita Leach, 1813 (Amphipoda: Melitidae) is a predominantly marine group with a cosmopolitan distribution in both circumtropical and temperate waters. However, records of Melita from inland waters such as fresh and brackish waters are limited. In this study, four new species of Melita are described from inland waters in the Ogas...

Freshwater habitats, especially cold springs, are environments in which the risk of extinction faced by organisms remains high due to human activities. To conserve endangered species, it is important to describe and name them. Here, a new, endangered freshwater anisogammarid amphipod species, Jesogammarus (Jesogammarus) acalceolus sp. nov. , found...

Freshwater habitats, especially cold springs, are environments in which the extinction risk faced by organisms remains high due to human activities. The extinction risks faced by many species go unrecognized prior to their extinction. To conserve endangered species, it is important to describe and name them. Here, we describe a new, endangered fres...

A new pardaliscid amphipod, Princaxelia marianaensis sp. nov. , is described from a single female captured at the Shinkai Seep Field, Mariana Trench, from a depth of 5,689–5,683 m. A key to species of Princaxelia is provided. This is the first species of Princaxelia to be described from the Mariana Trench, and the second report of this genus from t...

Two new species of Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000 included in the Maera-clade are described from Japan. Maera denticoxa sp. nov. was collected from Iwate and Hokkaido Prefectures and can be distinguished from its congeners by the small notches on the posteroventral margins of coxae 1-6. Quadrimaera angulata sp. nov....

A new species of the pontogeneiid amphipod Paramoera shakotanensis from the mouth of Horonaifu River, Hokkaido, Japan, is described. Paramoera shakotanensis sp. nov. can clearly be distinguished from its congeners by a combination of the following features: large eyes, deep antennal sinus without sharp incision, epimeral plate 3 with smooth posteri...

Talitrids are a highly diverse group of amphipod crustaceans that have colonized various terrestrial habitats. Three genera have successfully adapted to cave habitats on islands in the Pacific and Atlantic Oceans. However, the evolutionary origin of the Pacific troglobitic talitrids has remained unknown. We estimate the phylogenetic position of the...

A new pardaliscid amphipod, Nicippe beringensis , is described from the Bering Sea at depths between 520 and 536 m, and N. tumida Bruzelius, 1859 is redescribed based on specimens from Fredrikshald, Norway, near the species’ type locality. Nucleotide sequences of mitochondrial cytochrome c oxidase subunit I (COI) from the holotype and a paratype of...

This paper evaluates the scientific roles of the Swedish Vega Expedition led by Nordenskiöld, focusing on his collection of specimens obtained from Lake Biwa on October 15 and 16, 1879. These specimens, stored in the Swedish Museum of Natural History, Stockholm, were identified mostly by firsthand examination at the museum and some by examination o...

A new species of pseudocrangonyctid amphipod, Pseudocrangonyx wonkimi sp. nov. , was found in the groundwater of a cave in the southwestern Korean Peninsula. Pseudocrangonyx wonkimi sp. nov. is morphologically most closely related to P. joolaei Lee et al., 2020. However, P. wonkimi is clearly distinguished from P. joolaei by lacking sternal gills,...

The complete mitochondrial genome of a subterranean pseudocrangonyctid amphipod, Pseudocrangonyx joolaei, was determined in this paper. The complete mitogenome of P. joolaei was 14,814 bp in length with the typical 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and a control region (CR). The gene order of P. joolaei was unique in th...

We determined the mitogenome sequence of Jesogammarus (Jesogammarus) hinumensis Morino, 1993, which is the first complete mitogenome sequence in the family Anisogammaridae Bousfield, 1977. The complete mitogenome of J. (J.) hinumensis was 15,186 bp in length with the typical 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RN...

An environmental DNA (eDNA) detection method confirms the presence of the subterranean amphipod genus Pseudocrangonyx Akatsuka & Komai, 1922 in the city of Kyoto, Honshu, Japan for the first time in more than 90 years. Phylogenetic trees using partial sequences of the 16S rRNA gene of eDNA samples from Kyoto and specimens collected from various loc...

Neutrodiaptomus formosus (Kikuchi, 1928) is a calanoid copepod found in freshwater ponds in Japan. In the original description of this species, the illustration of the female habitus and the diagnostic description of the genital double somite were based on the copepodid V stage. Since there have been no studies describing the adult female of N. for...

A new species of calliopiid amphipod, Calliopius ezoensis, from the eastern coasts of Hokkaido, Japan, is described and named. Calliopius ezoensis is similar to the North Atlantic C. sablensis Bousfield & Hendrycks, 1997, but can be discriminated from it in possessing two rows of calceoli on the peduncular articles of antennae 1 and 2 of the female...

A new species of the eusirid amphipod, Rhachotropis reiwa is described from off Amamioshima Island, northwestern Pacific. The new species differs from its congeners in having large eyes, the middorsal tooth on pereonite 7, pleonite 3 and urosomite 1 without middorsal and dorsolateral teeth, the basis of pereopod 5 strongly produced posteriorly, and...

A new subterranean species of pseudocrangonyctid amphipod, Pseudocrangonyx joolaei, is described from the groundwater of a cave in South Korea. Pseudocrangonyx joolaei sp. nov. can be distinguished from its congeners by the number of sternal gills as well as a combination of the antennal sinus, the accessory flagellum of antenna 1, and the terminal...

A new species of pseudocrangonyctid amphipod, Pseudocrangonyx uenoi, is described from cave streams in Taga town, central Honshu, Japan. Previous molecular phylogenetic studies reported the taxonomic status of the Taga populations of Pseudocrangonyx as an undescribed species. We present the diagnostic features to discriminate P. uenoi from the othe...

A new species of podocerid amphipod, Podocerus jinbe, is named and described. This new species was collected from the gill rakers of the whale shark Rhincodon typus Smith, 1828 from off Yomitan Village, Okinawa Island, Japan. This is the first record of an amphipod associated with the whale shark. Podocerus jinbe sp. nov. is morphologically similar...

Pyatakovestia boninensis Morino and Miyamoto, 2015 is reported based on single female specimen from Ototojima Island, the Bonin Islands, Japan. This is the first record of the species in Ototojima Island. The specimen referred to P. boninensis differs from the original description (type locality: Hahajima Island) by the shape of coxal gill of pereo...

A new species of the maerid amphipod, Elasmopus nkjaf, from Miyako Island, Ryukyu Islands, Japan, is named and described. Additionally, nucleotide sequences of nuclear 28S ribosomal RNA and histone H3 as well as mitochondrial cy-tochrome c oxidase subunit I and 16S ribosomal RNA from its holotype and paratype were determined. Elasmopus nkjaf sp. no...

Two missing syntypes of the Japanese subterranean amphipod Procrangonyx japonicus (Uéno, 1930), the type species of Procrangonyx Schellenberg, 1934, were rediscovered in the collections of the Kyoto University Museum. The morphology of uropod 3, which has been considered the principal diagnostic character of the genus, is redescribed on the basis o...

The systematic status of the stygobitic amphipod, Paramoera relicta Uéno, 1971, was revisited based on morphological examination of the paratypes, and molecular phylogenetic analyses using a newly collected specimen from its type locality. The paratypes clearly showed that this species does not possess the “sinusoid” antennal sinus in the head, whi...

The complete mitogenome sequence of a subterranean pseudocrangonyctid amphipod, Pseudocrangonyx daejeonensis, was determined. The complete mitogenome of P. daejeonensis was 15,069 bp in length with the typical 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and a control region (CR). This is the first complete mi...

The calanoid copepod Pseudodiaptomus marinus Sato, 1913 is native to the coasts of East Asia, but has occurred in the San Francisco Estuary (SFE) as a non-indigenous species since 1986. Genetic analysis of the mitochondrial cytochrome b locus (400 bp) was used to infer the possible origin(s) of the introduced SFE population by comparison between th...

A new brackish-water species of melitid amphipod, Melitachoshigawaensis , from the Choshigawa River, Mie Prefecture, Japan, is named and described. Melitachoshigawaensissp. n. is distinguished from the most similar M.shimizui (Uéno, 1940) by having an elongate and weakly arched male uropod 3, and a deep and strongly hooked anterior lobe of the coxa...

A new species of the talitrid amphipod, Brevitalitrus pangkorensis, from a backshore forest of Pangkor Island, Malaysia, is named and described. This is the first record of Brevitalitrus Bousfield, 1971 from Malaysia. Brevitalitrus pangkorensis is morphologically similar to B. hortulanus (Calman, 1912), B. strinatii Stock, 1997, and B. wolffiBousfi...

Amphipods belonging to the crangonyctoid genus Pseudocrangonyx Akatsuka & Komai, 1922 constitute a major component of the subterranean environments in east Asia. The true species diversity of this group has been unsettled due to the lack of molecular data for P. shikokunis Akatsuka & Komai, 1922 and P. kyotonis Akatsuka & Komai, 1922 and the taxono...

A new landhopper talitrid, Myanmarorchestia nunomurai Nakano and Morino, sp. nov., from Yunnan Province, China is described. Since species of Myanmarorchestia were known only from Mt. Victoria of the Arakan Mountains of Myanmar, this is the first record of the genus from China. Myanmarorchestia nunomurai is characterised by its coxal gills on gnath...

A new subterranean species of pseudocrangonyctid amphipod, Pseudocrangonyx daejeonensis sp. n. is described from the interstitial waters in Daejeon, Korea. Pseudocrangonyx daejeonensis sp. n. is distinguished from three morphologically similar congeners, P. coreanus Uéno, 1966, P. febras Sidorov, 2009, and P. gudariensis Tomikawa & Sato, 2016, by t...

In an effort to broaden our understanding of the biodiversity and distribution of gregarines infecting crustaceans, this study describes two new species of gregarines, Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp., parasitizing a deep sea amphipod (Oradarea sp.). Amphipods were collected using the ROV Hyper-Dolphin at a depth...

The tri-spine horseshoe crab Tachypleus tridentatus is considered at risk and has been granted protection in Japan at least since the 1990s. The breeding areas in Okayama, Ehime and Saga prefectures, Japan, are protected by national and local laws, while in Hiroshima Prefecture the species has not been officially conserved by local administrations....

The systematic status of geographical variants of Arcuphantes hibanus Saito, 1992 belonging to the A. longiscapus species group, indigenous to western Honshu and Shikoku, Japan, was evaluated using morphological and molecular data. Two species, A. enmusubi Ihara, Nakano and Tomikawa, sp. nov. and A. occidentalis Ihara, Nakano and Tomikawa, sp. nov....

A new talitrid genus Solitroides is erected along with a description of a new species, Solitroides motokawai, from the Annamite Range, Vietnam. Solitroides motokawai, new genus & species, possesses the simplidactylate pereopods 3–7: this is the first record of simplidactylate landhoppers from the Northern Hemisphere. The simplidactylate Solitroides...

DOI: 10.1007/s12526-017-0758-4 Cite this article as: Narahara-Nakano, Y., Nakano, T. & Tomikawa, K. Mar Biodiv (2017). doi:10.1007/s12526-017-0758-4 Abstract Two species of the giant deep-sea amphipod genus Eurythenes are reported from two bathyal habitats in Japanese waters based on a morphological examination and DNA analyses. The new species E....

Amphipod crustaceans are dominant in subterranean habitats, and members of eight genera are endemic to groundwater environments in the Japanese Archipelago. The taxonomic status of two of these genera remains unclear, because their original descriptions were incomplete. The descriptions of the enigmatic subterranean monotypic genus Awacaris and its...

A new species of the pardaliscid amphipod, Nicippe recticaudata, from off Cape Toi, Japan, is named and described. This is the first record of Nicippe Bruzelius, 1859 from the western Pacific coast of the Japanese archipelago. Additionally, nucleotide sequences of nuclear 28S ribosomal RNA and histone H3 as well as mitochondrial cytochrome c oxidas...

This article reports fundamental researches organized for developing a novel teaching/learning system in secondary school science. A curriculum constructed by an effective integration of content-based and context-based curriculum arrangements is proposed for generating teaching/learning opportunities through various inquiry-based activities on the...

Two new species of anisogammaris amphipod, Jesogammarus (Jesogammarus) bousfieldi and J. (J.) uchiyamaryui, are described from mountain streams in Yamagata Prefecture and from brackish waters on Iki and Fukue Islands, Nagasaki Prefecture, Japan. Jesogammarus bousfieldi is morphologically almost similar to J. paucisetulosus Morino, 1984. However, J....

Praobdellid leech species have been known to infest vertebrate mucous-membrane; some of them have been assumed to be invertebrate bloodsuckers. Praobdellid individuals were found feeding on the Japanese freshwater crab, Geothelphusa dehaani, at Mt. Tsukuba, Ibaraki Prefecture, Japan. The leech had inserted its head into the intersegmental membrane...

Gammaridea (Amphipoda) comprises approximately 7900 species. To date, 37 freshwater species from 8 families and 21 terrestrial species from 1 family have been recorded in Japan. The Japanese freshwater amphipod fauna is characterized by high endemism at the species level. Among the 36 native species, 32 (~89 %) are endemic. However, at the family l...

A new deep-sea epimeriid, Epimeria abyssalis is described from the Kuril-Kamchatka Trench, in the northwestern Pacific. This species differs from its congeners in having a short rostrum and a telson with deep and narrow Y-shaped excavation. Epimeria abyssalis is the deepest recorded Epimeria species. A key to the north Pacific species of Epimeria i...

Opisa is a small amphipod genus including three species: O. eschrichtii (Krøyer, 1842) from the North Atlantic Ocean (Sars 1895; Bousfield 1987), the Arctic Ocean (Bousfield 1987), and the western Pacific Ocean (Stebbing 1906; Derzhavin 1929); O. odontochela Bousfield, 1987 from the southeast Alaska (Bousfield 1987); and O. tridentata Hurley, 1963...

A subterranean species of pseudocrangonyctid amphipod, Pseudocrangonyx gudariensis Tomikawa & Sato, sp. n., is described from the spring-fed stream Gudari-numa in Hakkoda Mountains, Aomori Prefecture, northern Japan. Pseudocrangonyx gudariensis is morphologically similar to P. coreanus Uéno, 1966 and P. febras Sidorov, 2009 based on its relatively...

A new species of the priscomilitarid amphipod, Priscomilitaris heike, from the Seto Inland Sea, Japan, is named and described. This new species is the third species of Priscomilitaridae and the second species of Priscomilitaris. Additionally, nucleotide sequences of nuclear 28S rRNA and histone H3 as well as mitochondrial cytochrome c oxidase subun...

Abyssododecas styx, a new genus and new species of Phtisicidae (Amphipoda), is described based on specimens collected from cold-seep sites at abyssal depths between 5313 and 7322 m in the Japan Trench, North Pacific, using the crewed submersible Shinkai 6500 and the Remotely-Operated Vehicle Kaiko. This is the deepest yet record of a caprellidean a...

Eocrangonyx japonicus (Uéno, 1930), a poorly known subterranean amphipod, is described and illustrated in detail based on a newly obtained specimen from a spring at Tachikawa, Tokyo, Japan. The generic assignment and newly found diagnostic features of E. japonicus are discussed. A key to all the species of Eocrangonyx is provided.

The oceanic calanoid copepod family Heterorhabdidae is unique in that it comprises both particle-feeding and carnivorous genera with some intermediate taxa. Both morphological and molecular (nuclear 18S and 28S rRNA) phylogenetic analyses of the family suggest that an evolutionary switch in feeding strategy, from transitions of typical particle-fee...

The taxonomic subdivision of certain Japanese freshwater amphipods into Jesogammarus jesoensis (Schellenberg, 1937), J. Hokurikuensis Morino, 1985, J. Fujinoi Tomikawa and Morino, 2003, and J. Shonaiensis Tomikawa and Morino, 2003 was reassessed using both morphological and molecular data. Putative diagnostic morphological characters did not exhibi...

FIGURE 2. Opisa takafuminakanoi sp. nov. A – K, holotype male, 7.6 mm, NSMT-Cr 24702; L – P, paratype female, 10.2 mm, NSMT- Cr 24703. A – D, right pereopods 4 – 7, medial views; E, right pleopod 1, anterior view; F, bifid plumose seta (clothes-pin seta) of right pleopod 1, anterior view; G, retinaculae of right pleopod 1, anterior view; H – J, lef...

FIGURE 1. Opisa takafuminakanoi sp. nov. A, paratype female, 8.4 mm, NSMT-Cr 24706; B – T, holotype male, 7.6 mm, NSMT-Cr 24702. A, habitus, lateral view; B – D, right epimeral plates 1 – 3, medial views; E, right antenna 1, medial view; F, calceoli of right antenna 1, medial view; G, right antenna 2, medial view; H, upper lip, anterior view; I, lo...

A new species of anisogammarid amphipod, Jesogammarus (Jesogammarus) ikiensis sp. n., is described from freshwaters in the Iki Island, Nagasaki Prefecture, Japan, based on results of morphological and molecular analyses. The new species is distinguished from all members of the genus by the combination of small number of setae on dorsal margins of p...

Vision, which consists of an optical system, receptors and image-processing capacity, has existed for at least 520 Myr. Except for the optical system, as in the calcified lenses of trilobite and ostracod arthropods, other parts of the visual system are not usually preserved in the fossil record, because the soft tissue of the eye and the brain deca...

To assess the taxonomic relationship between G. nipponensis and G. sobaegensis, morphological features and molecular phylogenetic relationships using the nuclear 28S rRNA and the mitochondrial COI genes were examined. Detailed morphological observations revealed that G. nipponensis and G. sobaegensis were clearly distinguishable. In addition to the...

A new species of amphipod, Sternomoera morinoi Tomikawa and Ishimaru, is described from subterranean aquatic habitats in Shiga Prefecture, Japan. In addition, Relictomoera tsushimana (Uéno, 1971) from a well on the island of Tsushima in Japan is transferred to Sternomoera and redescribed based on the holotype. Sternomoera morinoi sp. nov. is most s...

Four species including one new species of the genus Stephonyx are described from Japan: Stephonyx perexcavatus sp. nov., Stephonyx biscayensis (Chevreux, 19085. Chevreux , E. 1908. Diagnoses d'Amphipodes nouveaux provenant des campagnes de la Princesse Alice dans l'Atlantique nord. Bull Inst Océanogr., 117: 1–13. View all references), Stephonyx la...

Gammarus koreanus Ueno, 1940, which was originally described from the Korean Peninsula, is recorded from freshwaters of the Goto Islands, Japan. This is the first record of its occurrence in Japan. Molecular analyses using partial sequences of the 28S rRNA gene strongly support the identity of Japanese populations with G. koreanus. The Japanese spe...

A new amphipod Dulichiella takedai sp. nov. is described from the Ogasawara Islands, Japan, only the second species of the genus from Japan. Dulichiella takedai is morphologically similar to D. appendiculata (Say, 1818) from the USA and D. cuvettensis Appadoo & Myers, 2005 from Mauritius, but D. takedai differs from D. appendiculata in having slend...

Six hundred fifteen specimens of the cystidicolid nematode Salvelinema salmonicola (Ishii, 1916) were found in the swimbladder of a sockeye salmon Oncorhynchus nerka from Lake Toya, central Hokkaido, northern Japan. The stomach of this fish contained many, benthic gammaridean amphipods Jesogammarus jesoensis, which are most likely to serve as an in...

A new melitoid Amphipoda, Psammogammarus mawatarii, is described from Kuchinoerabu Island, Kagoshima Prefecture, Japan. This is the first record of the genus from Asia. The new species is morphologically similar to P. garthi, but differs from the latter in the following features: 1) lateral cephalic lobe of head not strongly produced; 2) head lacki...

A new species of the cyclopoid copepod genus Hemicyclops, H.xiamenensis, is described from plankton sampled at the mouth of the Jiulong River, southern China. This is the second species of the genus occurring in Chinese waters. The new species is readily distinguishable from its congeners by a combination of features of the fourth pediger, female g...

The current superfamilial classification of suborder Gammaridea, at least of the Japanese members, requires a full reassessment of their phylogenetic relationships. We investigated 17 species representing six families in three superfamilies from Japan, based on partial sequences of the mitochondrial 16S rRNA and nuclear 28S rRNA genes. Members of s...

Pseudocrangonyx shikokunis Akatsuka and Komai, 1922, a poorly known subterranean amphipod, is redescribed and illustrated in detail based on the syntypes from Tokushima Prefecture and four additional specimens from Hyogo Prefecture, Japan. Newly found diagnostic features and morphological variation of the species are discussed.

Methods for sampling and preparing, and a pictorial key to freshwater Amphipod (Arthropoda: Crustacea) were given. To date, nine species of freshwater amphipods from Hokkaido have been recorded. Amphipods are thought to be useful as an educational tool in the assessment of freshwater environments in Hokkaido. An example of an observation on the ass...

Barrowgammarus macginitiei (Shoemaker, 1955) and Spasskogammarus spasskii (Bulycheva, 1952) are reported based on specimens from Hokkaido, northern Japan. These are the first records of these two genera n Japan. The single specimen referred to B. macginitiei differs from the original description in having a relatively short antenna 1, distally tape...

Luciobliviidae, a new family in the superfamily Gammaroidea (Amphipoda: Crustacea), is described on the basis of species in the genus Lucioblivio gen. nov. from subterranean waters of Japan. Mesogammaridae Bousfield, 1977 is rediagnosed; Octopupilla gen. nov. from subterranean waters of Japan is described and Eoniphargus (Uéno, 1955) from subterran...

A new amphipod Nuuanu hanamurai sp. nov. is described from brackish waters in the Malaysian sector of the Strait of Malacca, as the first record of the genus from Malaysia. Nuuanu hanamurai, the twelfth member of the genus, is morphologically similar to N. kata Lowry & Watson, 2002 and N. merringannee (Barnard, 1974) in having a small dorsodistal t...

The genus Jesogammarus contains 16 species in two subgenera, Jesogammarus and Annanogammarus. To examine relationships among species in the genus, a molecular phylogenetic study including eight species of the former subgenus and four of the latter was conducted using partial DNA sequences of the mitochondrial COI and 12S rRNA genes. MP, NJ, and ML...

A new ingolfiellid amphipod, Ingolfiella inermis n. sp. is described from a coral sandy beach of Okinawa, southern Japan. The new species differs from its congeners in the following characters: head, pereionites, pleonites, and urosomites without dorsal setae; fleshy and moderately long telson; broad carpus of gnathopod 2 with some minute teeth and...

Amathillopsis takahashiae, a new amphipod species of the family Amathillopsidae from Japan, is described and illustrated. This is the first record of this family from Japan. The new species differs from the known species of Amathillopsis by the combination of eyes being present and pereonites 1-4 lacking middorsal teeth.

A revision of the genus Eogammarus is made based on type material and on collections from numerous localities. The following eight species are redescribed: E. kygi ( Derzhavin, 1923), E. barbatus ( Tzvetkova, 1965), E. confervicolus ( Stimpson, 1856), E. oclairi Bousfield, 1979, E. psammophilus Bousfield, 1979, E. schmidti ( Derzhavin, 1927), E. po...

On May 15, 2015 this sequence version replaced gi:111073812.

On May 15, 2015 this sequence version replaced gi:111073827.