A new species of Halacarsantia Wolff, 1989 (Crustacea, Isopoda, Asellota, Santiidae) from Wistari Reef, southern Great Barrier Reef, Australia

Halacarsantia acuta sp. n. is described from Wistari Reef, Capricorn Group, southern Great Barrier Reef, the first record of the genus from Australia. The new species differs from its congeners in having antenna flagellum composed of 8 articles; epipod apically acute, without setae, broad maxilliped endite and pereopod 1 basis with a short projection. A key to species of the genus is provided

Morphology of the gastric mill teeth in dotillid crabs (Crustacea: Brachyura: Dotillidae) from Indonesia

The gastric mill is a prominent structure in the digestive system of brachyuran crabs, consisting of a median tooth plate and a pair of lateral tooth plates. Among crab species that are deposit feeders, the morphology and size of the gastric mill teeth are correlated with the preferred substrate types and food spectrum. In this study, we provide a detailed description of the morphology of the median and lateral teeth of the gastric mills in eight species of dotillid crabs from Indonesia, and compare them in relation to habitat preferences and molecular phylogeny. Ilyoplax delsmani, Ilyoplax orientalis, and Ilyoplax strigicarpus have comparatively simple shapes of their median and lateral teeth, with fewer teeth on each lateral tooth plate compared to Dotilla myctiroides, Dotilla wichmanni, Scopimera gordonae, Scopimera intermedia, and Tmethypocoelis aff. ceratophora, which have more complexly shaped median and lateral teeth, with a greater number of teeth on each lateral tooth plate. The number of teeth on lateral tooth correlates with habitat preference, that is, dotillid crabs inhabiting muddy substrata have fewer teeth on the lateral tooth plate, and those inhabiting sandy substrata have a more teeth. Phylogenetic analysis using partial COI and 16S rRNA genes supports that teeth morphology is similar among closely related species. Therefore, the description of median and lateral teeth of the gastric mill is expected to contribute to the systematic study of dotillid crabs

Comparison of animal communities on benthic and drifting brown algae Sargassum horneri in the Seto Inland Sea, Japan

2018年5月，6月に広島県竹原市周辺海域にて着生している状態および流れ藻のアカモクを採集し，動物群集相の比較を行った。着生状態および流れ藻ともにソコミジンコ目カイアシ類，端脚類，等脚類，多毛類などがアカモク上で生息していることがわかった。Hornの重複度指数を用いて，月別の着生状態と流れ藻につく動物群集組成を比較したところ，6月の流れ藻における動物群集組成がほかと大きく異なることが明らかとなった。In May and June 2018, we collected both benthic and drifting large brown algae Sargassum horneri on the coast of Takehara City, Hiroshima Prefecture, Japan. The animal communities on benthic and drifting thalli were compared. Phytal animals such as harpacticoid copepods, amphipods, isopods, and polychaetes were predominantly found on both thalli. The Horn’s overlap index showed that the animal communities on drifting thalli in June 2018 were clearly different from those of the benthic thalli

The intertidal macrobenthic fauna of the Hatakejima Experimental Field, Wakayama Prefecture, Japan, in 2019

ファイル差し替え（2021-05-17）Hatakejima Experimental Field is located in Tanabe Bay, Wakayama Prefecture, Japan, which is composed of Hatakejima Island and Komarujima Islet, connected to the former in low tide. Hatakejima Island was purchased by Kyoto University and was designated as the “Hatakejima Experimental Field” in 1968. The year 2019 marks the 50th year of the long-term surveys that have been formally conducted on the experimental field since 1969 (i.e., the Century of Research Project). We conducted a field survey to record the macrobenthic fauna of the experimental field in 2019. A total of 168 species of 11 phyla were recorded in this survey. In each phylum, the number of species is listed as follows in descending order: Mollusca (78 spp.), Arthropoda (27 spp.), Echinodermata (23 spp.), Annelida (21 spp.), Cnidaria (7 spp.), Porifera (3 spp.), Nemertea (3 spp.), Platyhelminthes (2 spp.), Chordata (2 spp.), Bryozoa (1 sp.), and Hemichordata (1 sp.). We also recorded and discussed the influence of recent environmental changes around the Hatakejima Experimental Field. Tropical sea urchin species disappeared in the winter of 2017–2018 following the large meander of the Kuroshio Current, which led to decreasing water temperatures. The population of the seagrass Zostera japonica drastically decreased on the western sandy shore of the island in 2019, most likely because of two big typhoons in September 2018. We must conduct continuous observations to aid the recovery of seagrass-associated communities and protect the experimental field to keep high biodiversity of macrobenthic fauna in the future

Toxicity Assessment of the Xanthid Crab Demania cultripes from Cebu Island, Philippines

Several cases of poisoning resulting in human fatalities and stemming from the ingestion of coral reef crabs have been reported from the Indo-Pacific region. We assessed the toxicity of the unidentified xanthid crab collected from the Camotes Sea off the eastern coast of Cebu Island, central Visayas region of Philippines from the food hygienic point of view. All seven specimens, which were identified with Demania cultripes, collected in 2006 were toxic to mice irrespective of the season of collection and induced paralytic symptoms typical of tetrodotoxin (TTX) and paralytic shellfish poison (PSP). The activity was expressed in mouse unit (MU) being defined as the amount of TTX to kill a 20 g ddY male mice in 30 min after i.p. injection. Toxicity scores for viscera and appendages of specimens were 18.2 ± 16.0 (mean ± S.D.) and 4.4 ± 2.6 MU/g, respectively. The highest individual toxicity scores observed for viscera and appendages were 52.1 and 7.7 MU/g, respectively. The frequency of toxic samples was 100%. Toxin profiles as determined by high-performance liquid chromatography-fluorescent detection analysis (HPLC-FLD) revealed that TTX was the main toxic principle accounting for about 90% of the total toxicity along with 4-epi TTX and 4,9-anhydroTTX. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis revealed mass fragment ion peaks at m/z 376, 392 and 407, which were characteristic of the quinazoline skeleton (C9-base) specific to TTX. In addition, only a small amount of PSP containing gonyautoxins1–4 and hydroxysaxitoxin was detected. To our knowledge, this is the first report presenting evidence of occurrence of TTX and PSP in the xanthid crab D. cultripes inhabiting waters surrounding Cebu Island. From food hygienic point of view, people in coastal areas should be warned of the potential hazard of this crab in order to prevent its intentional or accidental consumption

Santia katoi sp. nov., a New Isopod Crustacean from Shirahama, Japan (Asellota : Santiidae)

Santia katoi sp. n. is described from Shirahama, Wakayama Prefecture, as the first record of the family Santiidae (Isopoda: Asellota) from Japan. The new species differs from its congeners in having a convex frontal margin on the head, coxal plates 5-7 each with two setae, and the male pleopod 1 with the distolateral projections on apex

Munnidae from Japan (Crustacea : Isopoda : Asellota)

Six species of Munna including two new to science and a species of Uromunna in Munnidae (Isopoda, Asellota) are reported from Japanese waters. Munna bispina sp. nov. is distinctive in having a pair of marked long robust sensory setae on frontal margin of the head, a long robust sensory seta on anterior margin of the eyestalk, and very long and slender antenna 2. Munna japonica sp. nov. lacks conspicuous dorsal and lateral setae both on pereon and pleon as in M. limicola G. O. Sars, 1866, M. subneglecta Gurjanova, 1936, M. tenuipes Kussakin, 1962, M. chilensis Menzies, 1962, M. lundae Menzies, 1962 and M. hovelli Poore, 1984, but distinguished from them in having the character combination of the pereopod I without sexual dimorphism, the pleopod I with a pair of distolaterally directed, long projections, and big pear-shaped pleotelson. Munna avatshensis Gurjanova, 1936, previously reported from the east coasts of Russia, were recorded from Japan for the first time. Munna stephenseni Gurjanova, 1933, M. tenuipes Kussakin, 1962 and Uromunna serricauda Muller, 1992 were redescribed in detail based on the Japanese materials newly collected

Bathycopea Tattersall 1905

Genus Bathycopea Tattersall, 1905 Bathycopea Tattersall, 1905: 12; Loyola e Silva, 1971: 215; Kussakin, 1979: 366; Harrison, 1984: 370; Harrison & Ellis, 1991: 933. Ancinella Hansen, 1905: 114. Type species. Bathycopea typhlops Tattersall, 1905, by monotypy. Other species. B. daltonae (Menzies & Barnard, 1959), B. parallela Birstein, 1963, B. ivanovi Birstein, 1963. Diagnosis. Pleon and pleotelson without process. Pleotelson posterior margin entire, ventrally excavate, without exit channel; posterior margin with short posterior projection at each side. Antennule peduncle article 1 twice as long as article 1, articles 1 and 2 robust; article 3 slender. Maxilliped: endite broad; articles 3 and 4 of palp without medial lobes. Pereopod 1 markedly subchelate; propodus sub-rectangular. Pleopods 1–3 with both rami longitudinally oblique. Male pleopod 2: exopod well-developed, ovate, reaching to half of endopod. Uropodal protopod widened laterally; endopod not stylet-shaped.Published as part of Shimomura, Michitaka, 2008, Bathycopea (Isopoda: Sphaeromatidea: Ancinidae) from Japan, with descriptions of two new species and redescription of B. parallela Birstein, pp. 25-49 in Zootaxa 1678 on page 26, DOI: 10.5281/zenodo.18034

A new species of Aspidophryxus (Isopoda, Dajidae), ectoparasitic on Mysidella hoshinoi (Mysidae) in Japan

A new dajid, Aspidophryxus izuensis sp. n., is described from seven females and six males found infesting the dorsal carapaces of specimens of Mysidella hoshinoi Shimomura, 2016 (Mysidae: Mysidellinae) associated with an unidentified species of sea anemone (Haloclavidae) from Izu-Oshima Island, Sagami Sea, central Japan. Aspidophryxus izuensis sp. n. differs from its congeners in having a body length about as long as wide, widest at the anterior part in females; an elongate frontal part of the cephalon, half as long as wide in females; the frontal margin of the cephalon exceeding the anterior margins of lateral lamellae in females; an unsegmented, vermiform, elongate pleon in females; and a uropod composed of a protopod and an inner and outer ramus in males. A key to worldwide species in the genus is provided