Osteological development of the lophiid anglerfish,lophius gastrophysus

The osteological development of the head skeleton and dorsal, pectoral, and anal fin supports, are described from cleared and stained specimens ofLophius gastrophysus larvae, ranging from 4.6 to 21.8 mm NL; the results are compared with those of juvenile (79.8 mm SL) and adult (398 mm SL) specimens. Tiny conical teeth are present on the premaxillary, dentary, palatine and vomer since early stage. The first three dorsal fin spines are initially positioned on the midline of body posterior to the supraoccipital, but they migrate forward with growth and become cephalic in juveniles. The forward movement of the dorsal spines is produced by the forward extension of the cartilaginous basal inside the subepidermal space. During the planktonic larval stage the pectoral fins are on the sides of body as in ordinary fishes, but they move ventrad and become leg-like in bottom living juveniles and adults. Ossification of the caudal complex ofL. gastrophysus larvae proceeds very slowly and only the 21.8 mm NL larva has an almost completely ossified caudal complex. Eight principal caudal rays are loosely attached on the posterior edge of the hypurals and no procurrent rays are present. Larvae have well developed parhypurapophysis at the mid-portion of the urostyle which transforms into keel-like structure in juveniles and adults.     

Characterization of microaerophilic bacteria isolated from the coastal waters of Tokyo Bay, Japan

Abstract A total of 84 strains of microaerophiles were isolated from the Edo River mouth, Tokyo Bay, Japan, and their morphological, physiological and biochemical properties and mole percent guanine-plus-cytosine contents (mol%) of DNAs extracted from them were examined. Eighty-eight to 100% of the strains, collected in summer, grew at 15–37°C but only 5% of the strains grew at 5°C. Seventy-seven to 100% of the strains, collected in winter, were able to grow at 10–25°C but 79% of the strains were unable to grow at 37°C. The shift in growth-range of bacteria strongly suggests that the microflora of estuarine microaerophiles changes seasonally. All the strains could grow at 50% seawater while 70 and 42% of the strains could not grow at 0 and 100% seawater, respectively.
On the other hand, 72 strains, out of the 84 strains, clustered into 9 phena using numerical taxonomy methods. The strains belonging to phena 1 through 9 were all Gram-negative, non-spore-forming rod-shaped organisms which were negative for susceptibility to vibrostatic agent O/129, H₂S production and acid from dulcitol, and the G + C contents of DNAs ranged from 29.8 to 56.6 mol%. However, almost all strains could not be identified and are suggested to be new species.     

Natural merodiploidy of the lux-rib operon of Photobacterium leiognathi from coastal waters of Honshu, Japan

Sequence analysis of the bacterial luminescence (lux) genes has proven effective in helping resolve evolutionary relationships among luminous bacteria. Phylogenetic analysis using lux genes, however, is based on the assumptions that the lux genes are present as single copies on the bacterial chromosome and are vertically inherited. We report here that certain strains of Photobacterium leiognathi carry multiple phylogenetically distinct copies of the entire operon that codes for luminescence and riboflavin synthesis genes, luxCDABEG-ribEBHA. Merodiploid lux-rib strains of P. leiognathi were detected during sequence analysis of luxA. To define the gene content, organization, and sequence of each lux-rib operon, we constructed a fosmid library of genomic DNA from a representative merodiploid strain, lnuch.13.1. Sequence analysis of fosmid clones and genomic analysis of lnuch.13.1 defined two complete, physically separate, and apparently functional operons, designated lux-rib1 and lux-rib2. P. leiognathi strains lelon.2.1 and lnuch.21.1 were also found to carry lux-rib1 and lux-rib2, whereas ATCC 25521T apparently carries only lux-rib1. In lnuch.13.1, lelon.2.1, lnuch.21.1, and ATCC 25521T, lux-rib1 is flanked upstream by lumQ and putA and downstream by a gene for a hypothetical multidrug efflux pump. In contrast, transposase genes flank lux-rib2 of lnuch.13.1, and the chromosomal location of lux-rib2 apparently differs in lnuch.13.1, lelon.2.1, and lnuch.21.1. Phylogenetic analysis demonstrated that lux-rib1 and lux-rib2 are more closely related to each other than either one is to the lux and rib genes of other bacterial species, which rules out interspecies lateral gene transfer as the origin of lux-rib2 in P. leiognathi; lux-rib2 apparently arose within a previously unsampled or extinct P. leiognathi lineage. Analysis of 170 additional strains of P. leiognathi, for a total of 174 strains examined from coastal waters of Japan, Taiwan, the Philippine Islands, and Thailand, identified 106 strains that carry only a single lux-rib operon and 68 that carry multiple lux-rib operons. Strains bearing a single lux-rib operon were obtained throughout the geographic sampling range, whereas lux-rib merodiploid strains were found only in coastal waters of central Honshu. This is the first report of merodiploidy of lux or rib genes in a luminous bacterium and the first indication that a natural merodiploid state in bacteria can correlate with geography.     

A new genus and two new species of marine free-living nematodes from the coastal waters of Southern Vietnam

A new genus and two new species of free-living marine nematodes from sediments in the coastal zone of the South China Sea (Vietnam) are described. Cyartonemoides gen. n. morphologically resembles Cyartonema Cobb, 1920, but differs from it in having a well-developed cephalic capsule. Cyartonemoides foetidus gen. n., sp. n. is the type and the only species of the genus. Campylaimus abnormis sp. n. differs from all species of the genus Campylaimus Cobb, 1920 by the shape of the amphidial fovea and shorter lateral fields.     

Modern dinoflagellate cysts in hypertrophic coastal waters of Tokyo Bay, Japan

A survey of dinoflagellate resting cysts in surface sedimentsamples was carried out in Tokyo Bay, Japan, to document theirhorizontal distribution. At least 21 different cyst types werefound. Dominant cyst types allowed the recognition of assemblageswhich form three different dinoflagellate cyst communities:the innermost part of the Bay, the central area and the moutharea. In all stations in Tokyo Bay, heterotrophic dinoflagellatecysts always occupied more than half of the cyst populations.Cysts of Polykrikos schwartzii/kofoidii are the most abundantheterotrophic species. These assemblages may reflect highlynutrient-enriched (hypertrophic) and turbulent water conditions.Among the cyst types found were probable ellipsoidal cysts ofAlexandrium tamarense. This is the first record of toxic Alexandriumspecies cysts in Tokyo Bay sediments.     

Ostreol A: A new cytotoxic compound isolated from the epiphytic dinoflagellate Ostreopsis cf. ovata from the coastal waters of Jeju Island,Korea

Ostreol A was isolated from cultures of the epiphytic dinoflagellate Ostreopsis cf. ovata from the coastal waters of Jeju Island, Korea. The compound, a non-palytoxin derivative, has a polyhydroxy chain ending with the primary amino group and contains an amide bond, along with two tetrahydropyran rings in the chain. Its chemical structure was elucidated by nuclear magnetic resonance (NMR) spectroscopy methods and confirmed by mass analysis. The compound exhibited significant cytotoxicity in the brine shrimp lethality test at a concentration of 0.9 μg/mL.     

New Kinorhyncha from Florida coastal waters

Four new species of Kinorhynchs are described from the West Atlantic coast off Fort Pierce, Florida, USA. They are the following: Antygomonas gwenae n. sp., Echinoderes riceae n. sp., Echinoderes adrianovi n. sp. and Pycnophyes norenburgi n. sp. All species were collected at the same locality called “20 miles station.” Samples were processed for standard granulometric data, yielding an estimated average particle diameter of 250 μm. The diagnostic characters and the general morphology of the new species are discussed in depth as well as the diversity and distribution of Kinorhyncha in the area.     

Stephos marsalensis new species (Copepoda, Calanoida, Stephidae) from coastal waters of Sicily, Italy

A new species of calanoid copepod, Stephos marsalensis, isdescribed from central Mediterranean coastal waters. It differsfrom congeners mainly in the structure of the fifth legs inboth sexes.     

Rhopalaea cloneyi (Ascidiacea, Cionidae), a new deep-water ascidian from the coastal waters of British Columbia

A new species of solitary ascidian from the British Columbia fjords, Rhopalaea cloneyi is described. R. cloneyi is characterized by its strong musculature, consisting of 14-15 longitudinal bands which are branched several times on the ventral side, converging to the endostylar band of the thorax. Its differences with the seven species of the genus Rhopalaea described up to the present are discussed. A checklist of the associated benthos found with the nine deep ascidians from this area observed with the PISCES IV submersible shows that R. cloneyi and Bathypera feminalba are found associated with the brachiopods Crania and Laqueus , the asteroid Mediaster aequalis and the anthozoid Stomphia .     

A new species of Stephos T.Scott, 1892 (Copepoda: Calanoida) from coastal waters of Sicily, Italy

Stephos cryptospinosus sp. nov., a new species of calanoid copepod,is described from Western Mediterranean coastal waters. It differsfrom other species of the genus in the structure of the fifthlegs in both sexes, and in having a small spinous process onthe posterolateral margins of the last prosomite in both sexes.     

Composition of the genus Leptosagitta of the family Sagittidae (Chaetognatha) with descriptions of four new species from coastal waters of the Northwestern Sea of Japan

Keys for the identification of the presently known species of the genus Leptosagitta (fam. Sagittidae) are presented. Four new species of this genus found in shallow waters of Vostok Bay, Amursky Bay (Peter the Great Bay), and Kievka Bay (all of the Sea of Japan) are described in detail: L. kiyashkoi sp. n., L. latyshevi sp. n., L. magna sp. n., and L. pauca sp. n.     

Description of the new phototrophic dinoflagellate Alexandrium pohangense sp. nov. from Korean coastal waters

The planktonic phototrophic dinoflagellate Alexandrium pohangense sp. nov. isolated from the coastal waters off Korea is described from living and fixed cells by light and scanning electron microscopy (SEM). DNA sequence data were collected from the small subunit (SSU), the large subunit (LSU), internal transcribed spacer regions (ITS1 and ITS2), and 5.8S of the ribosomal DNA (rDNA). The SSU and LSU rDNA sequences of the new dinoflagellate were 4–7% and 14–17%, respectively, different from those of Alexandrium minutum, Alexandrium ostenfeldii, Alexandrium tamutum, Alexandrium margalefii, and Alexandrium pseudogonyaulax, the most closely related species. In addition, the 5.8S rDNA sequence of the new dinoflagellate was also 12% different from those of A. minutum, A. ostenfeldii, A. tamutum, and Alexandrium peruvianum. In a phylogenetic tree based on LSU rDNA sequences, A. pohangense formed a clade with A. margalefii, and this clade was clearly distinct from the clade of A. minutum, Alexandrium diversaporum, A. tamutum, Alexandrium leei, A. ostenfeldii, and Alexandirum andersoni. Moreover, in a phylogenetic tree based on SSU rDNA sequences, A. pohangense was positioned at the base of the clade containing A. leei and A. diversaporum. Morphological analysis showed that A. pohangense has a Kofoidian plate formula of Po, 4′, 6′′, 6c, 8s, 5′′′, and 2′′′′, which confirmed its assignment to the genus Alexandrium. This dinoflagellate has a wide rectangular 1′ plate, the upper left side of which is slightly bent, protruding, and touching the 2′ plate, unlike A. margalefii, which has a wide rectangular 1′ plate that does not touch the 2′ plate, or A. pseudogonyaulax and Alexandrium camurascutulum, which have a narrower elongated pentagonal 1′ plate that touches the 2′ plate. Furthermore, the 1′ plate of A. pohangense meets the 1′′ plate as a straight vertical line, whereas that of A. camurascutulum meets the 1′′ plate as an inclined line because it is lifted by the intrusion of the 1′′ plate. In addition, A. pohangense had a relatively small ventral pore whose majority was located on the 4′ plate, unlike A. margalefii or A. pseudogonyaulax, which have a relatively large ventral pore whose majority is located on the 1′ plate. Furthermore, A. pohangense had pores of two different sizes on the cell surface, unlike A. margalefii and A. pseudogonyaulax, which have similar pores of only one size. On the basis of morphological and phylogenetic criteria, it is proposed that this is a new species of the genus Alexandrium.     

A light and electron microscopic study of a new species of centroheliozoon, Chlamydaster fimbriatus

The centroheliozoon Chlamydaster fimbriatus n.sp. has been studied in culture by light and electron microscopy. The cell body is surrounded by a fimbriated mucus envelope through which axopods extend. Each cell contains two or three contractile vacuoles and an eccentrically located nucleus with a single nucleolus. The cells have typical centroheliozoan characteristics such as a centroplast with a trilamellate disc, mitochondria with ribbon-like cristae, ball-and-cone kinetocysts, and a peripheral lacunar system. The axopodial axonemes possess a single hexagon of six microtubules. The genus is defined to include only centroheliozoa with a mucus coat. C. fimbriatus differs from the only other species recognized in this genus (C. laciniatus and C. sterni) in its size and number of arms. This is the first ultrastructural account of a species of the genus Chlamydaster.     

A new prickly dogfish,Oxynotus japonicus,from Japan

Oxynotus japonicus sp. nov. is described on the basis of a specimen collected by a bottom trawl at depths between 225 m and 270 m in Suruga Bay, Japan. It differs from other species of the genus in having the following combination of characters: spines of 1st and 2nd dorsal fins sloping slightly backward; length from tip of 1st dorsal spine to apex of 1st dorsal fin 2.6 times vertical height from tip of spine to fin base; length from tip of 2nd dorsal spine to apex of 2nd dorsal fin 1.9 times vertical height from tip of spine to fin base; and 2nd dorsal base 1.3 in interspace between 1st and 2nd dorsal fins.     

Heterocapsa busanensis sp. nov. (Peridiniales,Dinophyceae): A new marine thecate dinoflagellate from Korean coastal waters

During daily monitoring in Yongho Bay off Busan, Korea in 2019, an isolate of the dinoflagellate genus Heterocapsa was established in clonal culture. Light and electron microscopic examination revealed that the isolate was ellipsoid in shape, exhibiting a thecal plate arrangement (Po, cp, X, 5′, 3a, 7″, 6c, 5s, 5‴, 2ʹʹʹʹ) consistent with most other Heterocapsa species. A large, elongated nucleus was positioned on the left side of the cell, a single reticulate chloroplast was located peripherally, and a single, starch-sheathed, spherical pyrenoid was present in the episome or near the cingulum. Morphologically, the isolate most closely resembles H. circularisquama and H. illdefina. Transmission electron microscopic examination of whole mounts revealed that the isolate had two body scale types, one of which was a complex, three-dimensional, fine structure distinct from other Heterocapsa species, whereas the other simpler type was structurally similar to the scales of H. horiguchii. Molecular phylogeny based on rRNA sequences revealed that the isolate was distantly related to morphologically similar species, but formed a sister lineage to H. horiguchii, a species characterized by a similar body scale morphology. Based on morphological, ultrastructural, and molecular data, we proposed it as a new species, Heterocapsa busanensis sp. nov.     

Relationship between the bloom of Noctiluca scintillans and environmental factors in the coastal waters of Sagami Bay, Japan

In order to study the mechanism of the bloom formation of Noctilucascintillans, the relationship between the variation in the abundanceof N. scintillans and environmental factors was examined inthe coastal waters of Sagami Bay, Japan. Hydrographic (temperature,salinity, water stability), biological (chlorophyll a concentration,zooplankton biomass) and meteorological (rainfall, wind velocity,wind direction) factors were investigated from 1997 to 2004.For all years, the abundance of N. scintillans started to increasefrom March and reached a maximum in spring between April andMay. The abundance in 1997 and 2000 was relatively high comparedto the other years while the abundance in 1998 and 2004 wasrelatively low. A stepwise multiple linear regression analysisshowed that the wind direction and rainfall were significantlycorrelated with the variation in the abundance of N. scintillans.Our results suggest that bloom formation can be separated intoa three-step process: (i) initial increase in the abundanceof N. scintillans attributed to an increase in optimum hydrographicand biological factors, (ii) N. scintillans is then accumulatedby convergence of seawater by the factors of low rainfall andwind and (iii) swarmer-effects suggested enhanced bloom formation.Accumulation is considered to be a key trigger in this processof the formation of large-scale blooms. This paper was presented at Plankton Symposium III, held atFiguera da Foz, Portugal between 17 and 20 March 2005, underthe auspices of the University of Coimbra and the Universityof Aveiro, and coordinated by Mário Jorge Pereira andUlisses M. Azeiteiro.     

Three new species of nematodes (Nematoda: Enoplida) from coastal waters of Vietnam

Three new species of free-living nematodes of the order Enoplida from coastal shallow waters of northern Vietnam are described and illustrated. Paramesacanthion vietnamicum sp. n. is morphologically close to P. oxycephalum (Ditlevsen, 1926), P. truncum Vitiello, 1971, and P. hirsutum Warwick, 1970; however, it differs in lacking subcephalic setae and in having articulate cephalic setae in the males. Viscosia pygmaea sp. n. is morphologically similar to V. parva Kreis, 1929 but differs in having a shorter body and a shorter and thicker tail in the females. V. pygmaea is distinguished from V. megalaima (Ditlevsen, 1928) by its shorter body, longer cephalic setae, more slender tail, and the position of the vulva. Viscosia longicaudatoides sp. n. can be distinguished from V. parva and V. timmi Gagarin, Nguyen Vu Thanh, 2007 by its thinner body, longer and more slender tail, and shorter and narrower stoma. In contrast to V. timmi, it has short spicules and lacks vesicle-like cells between the gut and the longitudinal chords.     

A new ophichthid eel,Ophichthus megalops,from the Kumano-nada,Japan

An ophichthid eel,Ophichthus megalops sp. nov., is described from the Kumano-nada, off Owase, Mie Prefecture, Japan. This species is characterized by its large eye, dorsal fin origin far behind the tip of pectoral fin, vertebral number, dentition, and a distinct black smudge on the skin sheath of anal fin near the tip of tail.