Pacific Coast Of Southern Japan Research Articles

Long tubules of tentacular nematocysts in the moon jellyfish <i>Aurelia coerulea</i> (Semaeostomeae, Scyphozoa, Cnidaria) from Tanabe Bay, Pacific coast of southern Japan

We collected 43 medusae of Aurelia coerulea from Tanabe Bay, Wakayama, Japan, and measured the tubule lengths of 1,613 nematocysts at different growth stages: ephyra, juvenile, subadult, and adult. The median tubule lengths for ephyrae, juveniles, subadults, and adults were 72, 51, 79, and 58 µm, respectively. No nematocysts in ephyrae, juveniles, or subadults exceeded 200 µm in tubule length. In the tentacles of 15 adults, we detected nematocysts with tubule lengths exceeding 200 µm. The average proportion of nematocysts with long tubules was 9.1% in medusae with bell diameters of 110 mm or more, in contrast to only 1.0% in medusae with bell diameters of less than 110 mm. Among the 1,613 nematocysts examined, there were two different tubule groups with modes at 54 µm and 230 µm in length. Nematocysts in the short-tubule group were composed of microbasic euryteles and small isorhizas, whereas the long-tubule group was composed of only microbasic euryteles. These long tubules of microbasic euryteles can potentially penetrate not only large planktonic crustaceans but also human skin. The growth-related and intra-species variation in tubule length could also modify the degree of envenomation in humans.

A new snailfish of the genus Careproctus (Cottoidei: Liparidae) from the Pacific coast of southern Japan

A new snailfish, Careproctus tomiyamai, is described on the basis of four specimens collected from Suruga Bay, Tosa Bay, and the Hyuga-nada Sea, southern Japan (600–808 m depth). It is distinguished from all currently recognized congeners by the following combination of characters: total vertebrae 56–58; dorsal-fin rays 51 or 52; anal-fin rays 44–46; pectoral-fin rays 30–32; pyloric caeca 9–13; body slender, maximum depth 15.6–22.8% standard length (SL); teeth on both jaws strongly trilobed; pectoral fin shallowly notched, longest lower lobe ray 9.8–14.3% SL [46.0–60.4% head length (HL)]; proximal pectoral radials 4 (3 + 1), upper portion of 1st and 3rd radials, and lower portion of 2nd radial notched; fenestrae in pectoral girdle 2, between scapula and 1st proximal radial, and 2nd and 3rd proximal radials; pelvic disk oval, wider than long, length 3.4–4.3% SL (14.2–19.3% HL), moderately to deeply cupped; peritoneum black in preserved specimens.

Zenopsis filamentosa (Zeidae), a new mirror dory from the western Pacific Ocean, with redescription of Zenopsis nebulosa

A new mirror dory, Zenopsis filamentosa, is described from specimens collected off the Pacific coast of southern Japan (Mie and Tosa Bay), the Kyushu-Palau Ridge, Fiji, and Tonga. Within Zenopsis, the new species is most similar to Zenopsis nebulosa, widely distributed in the Pacific Ocean, in having nine dorsal-fin spines and similar buckler numbers along the anal-fin base. However, it can be distinguished from the latter in having 24–27 (modally 26) dorsal-fin soft rays (vs. 25–28, modally 27 in Z. nebulosa), 24–25 (usually 25) anal-fin rays (vs. 25–27, usually 26), filamentous membranes extending from the spinous portion of the dorsal fin, of length more than twice SL (vs. moderately elongated, not exceeding the caudal-fin posterior margin when adpressed); 6–9 (modally 7) bucklers between the pelvic and anus (vs. 7–10, modally 8), no bucklers above the anal-fin spines (vs. a small buckler present), and the pelvic fin with three to five dark stripes of all sizes (vs. lacking distinct markings in specimens >ca. 100 mm SL). Sequence variations on the mitochondrial DNA COI region demonstrated the validity of each species. Zenopsis nebulosa is redescribed, on the basis of western and Central Pacific Ocean specimens.

The Bigeye Scad, Selar Crumenophthalmus (Bloch, 1793) (Family Carangidae), New to the California Marine Fauna, with a List to and Keys for All California Carangids

The anomalously warm waters of the northeast Pacific 2014–2015 brought with it a variety of subtropical and tropical fish species previously unusual or absent from California waters (Bond et al., 2015; pers. comm. M. McCrea, pers. comm.; J. Shepherd). On 1 February 2015, Mr. Keichi Yamamoto speared a fish that we have identified as Selar crumenophthalmus (Bloch, 1793), the bigeye scad (Fig. 1). The fish was captured in the midwaters of a kelp bed (bottom depth 8 m) off Rancho Palos Verdes (33u489N, 118u249W), southern California. This is the first time this species has been reported from off California. The fish he speared was one of approximately 10 conspecifics that were swimming with a school of juvenile jack mackerel, Trachurus symmetricus (Ayres, 1855). This specimen is housed in the fish collection at the Natural History Museum of Los Angeles County, LACM 58288-1. We identified this fish (22.4 cm fork length) through the following diagnostic characters: Two papillae on the bone margin at the rear of the gill chamber (the lower one larger than the upper); the presence of a large eye (eye width greater than snout length) with adipose eyelid covers; and dorsal, anal, and pectoral fin counts and gill raker counts (Table 1). Meristics from our specimen fall within the range reported by other studies. Hardened scutes were present in the posterior lateral line. No finlets were present. The fish color was olive on dorsum, with a golden stripe along flanks, and a silvery belly. There was a diffuse golden ring around the eye. Bigeye scad are normally circumtropical. In the western Pacific, they have been found as far northward as the Pacific coast of southern Japan (Nakabo, 2002) and Sea of Japan (Parin, 2003). Previous to this capture, the eastern Pacific range was from Lagunas Ojo de Liebre-Guerrero Negro, central Baja California (Galvan-Magana et al., 2000) to Cabo Blanco, Peru (Chirichigno, 1974), including the Gulf of California (Smith-Vaniz in Fischer et al., 1995), Islas Galapagos (Grove and Lavenberg, 1997), Isla de Malpelo, Isla de Coco, Isla Clipperton, and Islas Revillagigedo (Robertson and Allen, 2008). This is a pelagic species found from surface waters to depths of 170 m (558 ft) (Randall et al., 1990, Allen and Robertson, 1994). It reaches a maximum length of 70 cm (Kuiter and Tonozuka, 2001). Of particular interest is that Mr. Yamamoto first observed a similar number of what were likely the same species in the same location in November 2014, also mixed in with juvenile jack mackerel. In addition, Mr. Yamamoto continued to observe bigeye scad at this location to as late as early March 2015, at this time swimming with a school of juvenile Pacific barracuda (Sphyraena argentea Girard, 1852). These sightings suggest that at least some bigeye scad may remain within a relatively circumscribed area for lengthy periods.

Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality.

The trematode genus Tellervotrema Gibson & Bray, 1982 was erected for Podocotyle-like species that parasitize archybenthal macrourid fishes (also known as grenadiers or rattails) and that possess no vitelline follicles dorsal to the ceca but do have a symmetrical pair of isolated groups of vitelline follicles in the posterior forebody. Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 is resurrected as a valid species based on an examination and re-description of holotype and paratype specimens collected from the intestine of the bathygadine macrourid Gadomus colletti Jordan & Gilbert from 518-582 m depth in Tosa Bay, off the Pacific coast of southern Japan. Tellervotrema beringi (Mamaev, 1965) Gibson & Bray, 1982 is re-described from specimens originally identified as T. katadara, collected from the intestine of the longfin grenadier, Coryphaenoides longifilis Günther, and found at 1,196 m depth off the Pacific coast of the Tōhoku region, northern Honshu, Japan. New host and locality records for T. beringi are presented along with a brief listing of museums housing type and voucher specimens of the three species now recognized in Tellervotrema. A comprehensive listing is given of all parasites reported from the two macrourid species relevant to this study and a key is presented for members of Tellervotrema. Finally, we hypothesize that the life cycles for T. beringi and T. katadara in the deep waters of the North Pacific Ocean off Japan most likely include a gastropod as a first intermediate host, one or more of a variety of invertebrates (amphipods, decapods, mysids) and/or finfish as second intermediate hosts, and the grenadiers, C. longifilis and G. colletti, as definitive hosts, respectively.

A new species of deep-sea synaphobranchid eel, Haptenchelys parviocularis (Anguilliformes: Synaphobranchidae), from Japan

A new synaphobranchid eel Haptenchelys parviocularis is described on the basis of 15 specimens (467–840 mm in total length) collected off the Pacific coast of southern Japan, in depths of 4,093–4,866 m. The new species is distinguishable from its single congener, Haptenchelys texis Robins and Martin in Robins and Robins 1976, in having the following combination of characters: total vertebrae 127–137, caudal vertebrae 90–98; snout short, length 42.5–53.1 % upper-jaw length; eye much smaller than gill-slit aperture, diameter 37.5–59.4 % gill-slit length and 11.8–16.9 % upper-jaw length; eye positioned closer to middle of mouth gape (postorbital length-to gape 23.5–32.5 % head length and 40.5–50.9 % upper-jaw length); gill-slit aperture wide (15.8–22.1 % head length and 24.8–35.7 % upper-jaw length), orientation oblique to body axis.

The Cumacean (Crustacea: Peracarida) Genus Petalosarsia (Pseudocumatidae) from the Pacific Ocean

The distribution of the cumacean family Pseudocumatidae is restricted to the North Atlantic, Mediterranean and brackishwaters of the Pont-Caspian region, except for three known species of the genus Petalosarsia. The present study describes ninespecies of Petalosarsia from Japanese waters, the Sulu Sea, the North-west Pacific, the Indo-West Pacific, and the Tasman Sea,Australia. The occurrence of P. declivis (Sars, 1865) in northern Hokkaido agrees with the reported circumpolar distribution ofthis species. Four species from the Pacific coast of southern Japan and the East China Sea, P. brevirostris Gamô 1986, P. ovalissp. nov., P. ryukyuensis sp. nov. and P. gamoi sp. nov., are characterized by prominent dorsolateral carinae with teeth anteriorlyand the basis of the 2nd maxilliped with a semicircular plate on the ventral surface. Nine specimens collected from the Sulu Seaincluded five species, P. brevirostris, P. gamoi, P. jonesi sp. nov. P. suluensis sp. nov. and P. longicauda sp. nov. The latterthree species were characterized by no or faint dorsolateral carinae on the carapace. Among them, P. jonesi was similar to P.longirostris from the eastern tropical deep Atlantic. Petalosarsia australis sp. nov. from the Tasman Sea is characterized by onefaint pair of dorsolateral carinae running for the entire length of the carapace. The species richness of Petalosarsia in the SuluSea and the Indo-West Pacific suggests a wide distribution of ancestors of Pseudocumatidae around the ancient Tethys Sea, with the Ponto-Caspian region located near the center. The habitat of Petalosarsia was mostly deeper than 200 m.

Avitocaligus evoxymetoponicola, a new species of Caligidae (Copepoda, Siphonostomatoida) parasitic on Poey’s scabbardfish, Evoxymetopon poeyi Günther, 1887 (Trichiuridae), from Japan

Avitocaligus evoxymetoponicola nov. sp. (Copepoda, Siphonostomatoida, Caligidae) is described as the second representative of the genus based on specimens of both sexes recovered from the branchial and nasal cavities of Poey’s scabbardfish, Evoxymetopon poeyi Gunther, 1887 (Trichiuridae), caught off Cape Muroto, on the Pacific coast of southern Japan. This new species is easily distinguishable from the type species, A. assurgericola Boxshall & Justine, 2005, parasitic on the razorback scabbardfish, Assurger anzac (Alexander, 1917), by the contour of the lateral and dorsoposterior plates of the genital complex and the ventral plates of the first abdominal somite, in addition to the possession of postantennal processes and marginal membranes on the frontal plates. The description of the male is given here for the first time for this genus. The maxilliped of the male is unique in having a rod-like myxal process.

A review of the genus Platyrhina (Chondrichthys: Platyrhinidae) from the northwestern Pacific, with descriptions of two new species

The genus Platyrhina from the northwestern Pacific was reviewed, including a redescription and neotype proposal for Platyrhina sinensis (Bloch and Schneider 1801), and the description of two new species. Platyrhina limboonkengi Tang 1933 is relegated to the synonymy of P. sinensis, both species having two rows of hooked thorns on the mid-dorsum of the tail. Specimens previously widely identified as P. sinensis, but characterized by one row of such hooked thorns, represented an undescribed species, herein named Platyrhina tangi Iwatsuki, Zhang and Nakaya sp. nov. Platyrhina hyugaensis Iwatsuki, Miyamoto and Nakaya sp. nov., known from specimens limited primarily to the Hyuga Nada Sea, off Miyazaki, the Pacific coast of southern Japan, is similar to P. tangi in having one row of hooked thorns on the mid-dorsum of the trunk and tail, but differs in having larger hooked thorns, not encircled by light yellow or white pigment on the orbital, nape and scapular regions, and a pair of hooked thorns (absent in P. tangi) anteriorly on the scapular region. Nominal species are discussed and key to northwestern Pacific species of Platyrhina is provided.

Genetic divergence in Ditrema jordani (Perciformes: Embiotocidae) from the Pacific coast of southern Japan, as inferred from mitochondrial DNA sequences

Genetic divergence in Ditrema jordani was investigated from sequence variations on the mitochondrial cytochrome b gene. Clear genetic differences were found between specimens collected from the Mie and Shizuoka prefectures (westward of Izu Peninsula) and those from the Kanagawa and Chiba prefectures (eastward of Izu Peninsula). The uncorrected genetic distance between the two groups, which may represent separate taxa, was much greater (3.1–3.7%) than that between D. temminckii and D. viride (1.1–2.4%), and between two subspecies of D. temminckii (0.8–1.3%), suggesting that the Izu Peninsula acts as a stable geographic barrier to gene flow between the D. jordani groups. The clear genetic divergence between the two geographic populations of D. jordani may be partly related to direct development (viviparity) and low dispersal ability in the genus.

An underwater photograph of Sphyraena iburiensis (Perciformes: Sphyraenidae) from the Red Sea: first record outside Japanese waters

Sphyraena iburiensis, a small-sized barracuda (family Sphyraenidae) recently described by Doiuchi and Nakabo (2005), belongs to the S. obtusata group sensu Doiuchi and Nakabo (2005), characterized by two gill rakers on the first gill arch. The original description of S. iburiensis was based on the holotype and paratypes collected from Iburi, Kochi Prefecture, with additional paratypes from Kushimoto, Wakayama Pref. and Kawana, Shizuoka Pref., all located on the Pacific coast of southern Japan. Subsequently, a specimen of S. iburiensis was reported from Fukaura, Ehime Pref., Japan by Takagi et al. (2010), although additional records based on underwater photographs include Taketomi Island, Ryukyu Islands, Japan (KPM-NR 12009, taken by J. Nakamoto) and Hachijo Island, Izu Islands, Japan (KPM-NR 91935–91937, taken by S. Kato); the photographs are deposited at the Image Database of Fishes, Kanagawa Prefectural Museum of Natural History (http://research.kahaku.go.jp/zoology/ photoDB/). To date, therefore, S. iburiensis has been considered endemic to Japanese waters, although Sphyraena obtusata and Sphyraena pinguis, also members of the S. obtusata group, are both widely known from the IndoWest Pacific (Doiuchi and Nakabo 2005). In 10 October 2008, an underwater photograph of S. iburiensis (Fig. 1) was taken at Shams Alam reef, Wadi Gimal area, Red Sea coast of Egypt (24 4101800N, 35 0500800E), by the second author (S. B.). This record is the first of S. iburiensis outside Japanese waters; the fishes pictured agree well with the diagnostic characters of the S. obtusata group given by Doiuchi and Nakabo (2005), viz. pored lateral-line scales ca. 81–84; scales below lateral line ca. 10 , orbit diameter ca. 5.5% in standard length, posterior tip of maxilla not reaching anterior margin of eye, anterior tip of lower jaw without a pointed fleshy knob, origin of first dorsal fin well behind that of pelvic fin, and body with two longitudinal stripes on the lateral surface. Among the S. obtusata group, S. iburiensis differs from S. pinguis as follows: two longitudinal stripes, lower stripe running through upper part of pectoral-fin base (a single stripe running above pectoral-fin base in S. pinguis) (Doiuchi and Nakabo 2005). Sphyraena iburiensis differs from S. obtusata in having both longitudinal stripes distinct (somewhat indistinct in S. obtusata), the lower stripe extending to the caudal-fin base just below the lateral line (lower stripe joining lateral line midway between end of second dorsal-fin base and caudal-fin base, extending to middle of caudal-fin base in the latter), in addition to 10 – 11 scales below the lateral line (8 –9 in S. obtusata) (Doiuchi and Nakabo 2005). The individuals in Fig. 1 agree closely with the original description of these characters. Shams Alam reef is a large, semi-enclosed lagoon characterized by sandy areas, seagrass beds, isolated coral reefs and fringing reefs. The pictured individuals were observed at a depth of between 1 and 2 m (over about 3 m). Approximately 20 individuals with total lengths of R. Doiuchi (&) Fisheries Experimental Station, Wakayama Research Center of Agriculture, Forestry, and Fisheries, 1557-20 Kushimoto, Higashimuro-gun, Wakayama 649-3503, Japan e-mail: doiuchi_r0001@pref.wakayama.lg.jp

The megalopidae, a new family of fishes for fauna of Russia

According to contemporary notions, the fossil monotypical family of tarpons, i.e., Megalopidae, belonging to the order Elopiformes of subclass Neopterygii and known from the Paleocene (Danil’chenko, 1964; Forey, 1973; Nelson, 1994), is represented in the recent fauna by two subtropical and tropical, epipelagic species widespread in the waters of all oceans except the Arctic Ocean (Lindberg and Legeza, 1965; Lindberg, 1971; Nelson, 1994). One of them, i.e., IndoPacific tarpon Megalops cyprinoides , occurs off the Pacific coast of southern Japan and in the southern part of the Sea of Japan near Pusan and Sado Island and Ryukyu Island (Hayashi, 1972; Chyung Moon-ki, 1977; Masuda et al., 1984; Honma Aoyagi, 1990; Choi Youn et al., 2002; Nakabo, 2002).

Distribution of jack mackerel (Trachurus japonicus) larvae and juveniles in the East China Sea, with special reference to the larval transport by the Kuroshio Current

AbstractHorizontal distribution patterns of jack mackerel (Trachurus japonicus) larvae and juveniles were investigated in the East China Sea between 4 February and 30 April 2001. A total of 1549 larvae and juveniles were collected by bongo and neuston nets at 357 stations. The larvae were concentrated in the frontal area between the Kuroshio Current and shelf waters in the upstream region of the Kuroshio. The abundance of small larvae (<3 mm notochord length) was highest in the southern East China Sea (SECS) south of 28°N, suggesting that the principal spawning ground is formed in the SECS from late winter to spring. Jack mackerel also spawned in the northern and central East China Sea (NECS and CECS, respectively), as some small larvae were also collected in these areas. In the SECS, the abundance of small larvae was highest in February and gradually decreased from March to April. The habitat temperature of small larvae in the SECS and CECS (20–26°C) was higher than that in the NECS (15–21°C), suggesting higher growth rates in the SECS and CECS than in the NECS. The juveniles (10‐ to 30‐mm standard length) became abundant in the NECS off the west coast of Kyushu Island and CECS in April and were collected in association with scyphozoans typical of the Kuroshio waters. However, juveniles were rarely collected in the SECS, where the small larvae were concentrated. Considering the current systems in the study area, a large number of the eggs and larvae spawned and hatched in the SECS would be transported northeastward by the Kuroshio and its branches into the jack mackerels’ nursery grounds, such as the shallow waters off the west coast of Kyushu and the Pacific coast of southern Japan.

The Sphyraena obtusata group (Perciformes: Sphyraenidae) with a description of a new species from southern Japan

Sphyraena iburiensis sp. nov. is described, and taxonomic reviews are provided for S. obtusata and S. pinguis. These species, characterized by having 2 gill rakers, are defined as the S. obtusata group. Sphyraena iburiensis, known only from the Pacific coast of southern Japan, is characterized by 8.5–9.5 scales above the lateral line, a single row of scales in the groove along the lower margin of the suborbital region from the posterior tip of the maxilla to below the eye (= suborbital groove) not covered with skin, 2 distinct longitudinal stripes on the lateral surface of the body when fresh (upper stripe usually lost in preserved specimens), the lower stripe reaching the caudal-fin base just below the lateral line. Sphyraena obtusata, distributed in the Indo-West Pacific, is characterized by 5–7.5 scales above the lateral line, a single row of scales in the suborbital groove covered with skin, 2 somewhat indistinct longitudinal stripes on the lateral surface of the body when fresh (upper stripe usually lost in preserved specimens), the lower stripe joining the lateral line midway between the end of the second dorsal-fin base and caudal peduncle and extending to the middle of the caudal-fin base. Sphyraena pinguis, distributed in the Indo-West Pacific, is characterized by 7.5–9.5 scales above the lateral line, a single row of scales in the suborbital groove not covered with skin, and a single longitudinal stripe on the lateral surface of the body joining the lateral line slightly before or just below the end of the second dorsal-fin base and extending to the middle of the caudal-fin base. Seven (S. aureoflammea, S. brachygnathos, S. flavicauda, S. grandisquamis, S. langsar, S. lineata, and S. strenua) and 2 (S. chrysotaenia and S. schlegelii) nominal species are regarded as junior synonyms of S. obtusata and S. pinguis, respectively. In addition, lectotypes are designated for S. flavicauda, S. langsar, S. lineata, and S. obtusata. A key to the three species of the S. obtusata group is provided.

A new species of Sebastes (Scorpaeniformes: Scorpaenidae) from the Pacific coast of southern Japan

A new rockfish, Sebastes kiyomatsui, is described on the basis of 13 specimens from the Pacific coast of southern Japan. The new species resembles S. scythropus in having two sharp preorbital and robust preocular, supraocular, and postocular spines, but differs from the latter in having a black blotch on the opercle not extending to the subopercle, indistinct crimson marks on the body, blackish region of the oral cavity reaching to the prevomer and palatine, blackish tongue, a small ridge on the upper edge of the lachrymal, somewhat larger orbit, somewhat lower caudal peduncle, and seven lower unbranched pectoral fin rays. Sebastes kiyomatsui is a deep water (ca. 250 m) inhabitant.

Maturation and spawning of the small penaeid shrimp Metapenaeopsis dalei in Tosa Bay, Pacific coast of southern Japan

SUMMARY: Seasonal changes in the percentage of mature female Metapenaeopsis dalei were studied histologically, and the annual cycle of maturation and spawning of this species was discussed. Specimens were collected at night by a beam trawler in Tosa Bay (33°N, 133°E) during the period from April 1995 to March 1996. All individuals had a gonado somatic index [GSI = 100 (gonado weight/body weight)] of higher than 8, and 66.7% of those individuals with a GSI of 6–8 had oocytes in the late phase of the prematuration stage after germinal vesicle shrinking and migrating to the margin of the oocyte or had oocytes in the maturation stage. Such individuals with developed oocytes appeared in April, June, July, August, October, November and March. Individuals with a GSI above 6 appeared throughout the year, except during September and February. Individuals with ovulated oocytes were sampled in March when the water temperature near the bottom depths was lowest (15.4°C) during the year, being similar to February (15.1°C). These facts indicate that maturation occurs all year-round and suggests that spawning in the Metapenaeopsis dalei population in Tosa Bay occurs all year-round. This is the first report of year-round maturation in penaeid shrimps in Japanese waters.