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Ciguatera fish poisoning (CFP) is a serious health problem in tropical regions and is caused by the bioaccumulation of lipophilic toxins produced by dinoflagellates in the genus Gambierdiscus. Gambierdiscus species are morphologically similar and are difficult to distinguish from one another even when using scanning electron microscopy. Improved identification and detection methods that are sensitive and rapid are needed to identify toxic species and investigate potential distribution and abundance patterns in relation to incidences of CFP. This study presents the first species-specific, semi-quantitative polymerase chain reaction (qPCR) assays that can be used to address these questions. These assays are specific for five Gambierdiscus species and one undescribed ribotype. The assays utilized a SYBR green format and targeted unique sequences found within the SSU, ITS, and the D1/D3 LSU ribosomal domains. Standard curves were constructed using known concentrations of cultured cells and 10-fold serial dilutions of rDNA PCR amplicons containing the target sequence for each specific assay. Assay sensitivity and accuracy were tested using DNA extracts purified from known concentrations of multiple Gambierdiscus species. The qPCR assays were used to assess Gambierdiscus species diversity and abundance in samples collected from nearshore areas adjacent to Ft. Pierce and Jupiter, Florida USA. The results indicated that the practical limit of detection for each assay was 10 cells per sample. Most interestingly, the qPCR analysis revealed that as many as four species of Gambierdiscus were present in a single macrophyte sample. [ABSTRACT FROM AUTHOR]

Gambierdiscus species produce toxins that cause ciguatera fish poisoning (CFP), the most common nonbacterial illness associated with fish consumption worldwide. Understanding the role that individual Gambierdiscus species play in causing CFP is hampered because the morphologically similar species in the genus are difficult to distinguish. Ambiguities in the description of the type species Gambierdiscus toxicus also exist. This paper presents detailed line drawings along with additional scanning electron microscopy (SEM) and light micrographs to more fully characterize the six known Gambierdiscus species in addition to describing four new species, Gambierdiscus caribaeus sp. nov., Gambierdiscus carolinianus sp. nov., Gambierdiscus carpenteri sp. nov., and Gambierdiscus ruetzleri sp. nov. All four of the new species are photosynthetic and epibenthic and have a Kofoidian plate formula of Po, 3′, 7″, 6C, 6 or 7S, 5′″, 1p, and 2‴′. Establishment of these species is supported by both morphological differences and three independent phylogenetic analyses utilizing small-subunit, as well as D1-D3 and D8-D10 large-subunit rDNA gene sequences. During the course of this study it became apparent that the description of the type species, G. toxicus, included more than one species. Since no type material exists we propose that Fig. 1 in Adachi and Fukuyo (1979) be designated as the lectotype for this species and that the epithecal view of isolate GTT-91 shown in Fig. 1 from Chinain et al. (1999) be designated as the epitype. The GTT-91 isolate has been well characterized genetically and the original SEM stub of this isolate archived at the Smithsonian Institution has been re-examined to provide a more detailed morphological analysis of the epitype. [ABSTRACT FROM AUTHOR]

As part of a long-term study of benthic dinoflagellates from the Belizean barrier reef system, we report a new species: Prorocentrum levis M. A. Faust, Kibler, Vandersea, P. A. Tester et Litaker sp. nov. P. levis cells are oval in valve view and range in size from 40 to 44 μm long and 37 to 40 μm wide. Each valve surface is smooth, with 221–238 valve pores and 99–130 marginal pores. These pores are uniformly small and range in diameter from 0.13 to 0.19 μm. Asexual reproduction in P. levis is atypical, occurring within a hyaline envelope, and produces long branching chains of adherent cells. A phylogenetic analysis of SSU rDNA indicated that of the Prorocentrum species sequenced so far, P. levis was most closely related to P. concavum. P. levis produces okadaic acid and dinophysis toxin-2 (DTX2). Further, SEM observations and SSU rDNA sequence for P. belizeanum M. A. Faust, which was isolated at the same time, are also presented. [ABSTRACT FROM AUTHOR]

Two new heterotrophic Protoperidinium species are described from oceanic waters from The Gulf Stream, SW Atlantic Ocean and Belizean Atlantic Barrier Reef Ecosystems, Caribbean Sea. Protoperidiniurn novella Faust sp. nov. and P. concinna Faust sp. nov. show a plate formula of 4′, 1a, 7″, 4C(3+t), 6S, 5‴, and 2‴, which is atypical for the genus. It is characterized by a miniscule flat closure on the extreme anterior of the pointed apical horn. Apical pore complex is absent. Apical ventral plate 1′ disconnects from the tip of the apical horn and connects directly to the anterior sulcal plate (Sa) along a straight line of the longitudinal axis of the cell's sagittal plane. The shape and position of the intercalary plate (1a) is another distinctive feature for these species, the presence of only one 1a plate. The thecal plate features of P. novella and P. concinna justifies the establishment of the new subgenus, Testeria Faust subgen, nov. The relationship with other congeneric species and the position within the genus Protoperidinium are discussed. [ABSTRACT FROM AUTHOR]

Prorocentrum minimum (Dinophyceae) is a red tide­forming toxin­producing planktonic microalga from coastal waters worldwide. In this study, the morphology of natural and cultured populations of P. minimum was examined to investigate whether the species can be split morphologically into more species. The diacritical features of cell shape and size, ornamentation of thecal plates, and architecture of the apical pore area and intercalary band were studied from scanning and light micrographs. Cell size of P. minimum is similar in Baltic Sea samples and a culture from the Chesapeake Bay, USA. Cell shape varies from triangular to oval­round including intermediate forms in valve view. The thecal surface is covered by evenly distributed short spines, while the circular thecal pores are mainly situated near the valve margin. The intercalary band is rim-like, striated and covered with short evenly distributed spines. The architecture of the apical pore area is ornate and more complex than previously pointed out. It is V­shaped, located on the right valve in a shallow depression and accommodates a large elongated flagellar pore, and a small round auxiliary pore. Four distinct apical features are present: next to the auxiliary pore there is a curved collar, and adjacent to the flagellar pore arise a forked double tooth, a short single tooth, and a ridged edge near the left valve margin. Our study suggests that the ornamentation of the apical pore area of P.minimum is independent of cell shape or growth place,and it is considered a stable morphological character of this cosmopolitan morphospecies. [ABSTRACT FROM AUTHOR]

A new marine heterotrophic dinoflagellate species, Protoperidinium belizeanum sp. nov., from a coral reef-mangrove pond was identified from scanning electron micrographs. Recognition of this new species was based on unique features of the thecal morphology, which included cell size and shape, presence of short and wide postcingular plates, sulcal architecture, antapical spines, and intricate thecal plate patterns of ridged hexagonal depressions. The thecal plate formula is as follows: Po, X, 4′, 3a, 7″, 4C (3+t), 6S, 5‴, 2″″. Species association of P. be-lizeanum sp. nov. within the genus Protoperidinium , its habitat, and associated dinoflagellates species are discussed. [ABSTRACT FROM AUTHOR]

A new marine heterotrophic dinoflagellate species, Protoperidinium belizeanum sp. nov., from a coral reef-mangrove pond was identified from scanning electron micrographs. Recognition of this new species was based on unique features of the thecal morphology, which included cell size and shape, presence of short and wide postcingular plates, sulcal architecture, antapical spines, and intricate thecal plate patterns of ridged hexagonal depressions. The thecal plate formula is as follows: Po, X, 4′, 3a, 7″, 4C (3+t), 6S, 5‴, 2″″. Species association of P. be-lizeanum sp. nov. within the genus Protoperidinium , its habitat, and associated dinoflagellates species are discussed. [ABSTRACT FROM AUTHOR]

A new species of planktonic dinoflagellate, Prorocentrum arabianum isolated from the Gulf of Oman, is described using both scanning electron microscopy (SEM) and light microscopy. This clonal isolate has the following morphological characteristics: (1) cell shape is asymmetric; (2) thecal surface is rugose, covered with small poroids; (3) periflagellar area is unornamented, and (4) intercalary band is horizontally striated. Analysis of P. arabianum confirms the production of one cytotoxic compound and one ichthyotoxic compound. P. arabianum is the second known toxic planktonic Prorocentroid dinoflagellate. [Copyright &y& Elsevier]

Discusses the morphology and molecular analyses of toxic species of Gambierdiscus or dinophyceae. Use of scanning electron micrographs to study dinoflagellate species; Comparison of the morphology of Gambierdiscus species with the type species Gambierdiscus toxicus; Culture extracts of species.

Reports on the cells of Pyrophacus steinii Wall et Dale which are round and lens shaped and have an anteroposteriorly compressed theca. Description of the epitheca and cingulum; Observation of pregametic stages of P. steinii during cell division via binary fission; Presence of gametes with gymnodinoid morphology within the parental cells.

Three new bwnthic, photosynthetic dinoflagellate species, Prorocentrum norrisianum, from floating detritus and coral rubble of Central America are described from scaning electron micrographs. Species were identified based on shape size surface micromorphology ,thecal plate ornamentation, and architecture of the perflagellar area and intercalary band. Cells of P. norrisianum are avate with a cell size of 20-25 μm long and 13-16 μm wide. The theca is delicate its surface smooth, pores species specific with 95-105 pores per valve, Pores are round with a diameter of about 0.1 μm The periflagellar area is V-shaped located on the right valve in a shallow depression. It has no ornamentation.The flagellar and auxiliary pores are unequal in size. The interacalry band is smooth. Proroentrum tropicalis cells are avoid, 50-55 μm long and 40-45 μm wide in valve view with maximum width behind the middle region, narrow at the right valve, is a V-shaped periflagellar area, situated in the right valve, is a V-shaped wide triangle with a deeply indented depression; the left valve exhibits a flat ridge. The periflagellar area is unornamented and the flagellar and auxiliary pores are unequal is size. The valve surface is rugose with evenly distributed galve poroids. Each poroid appears to have a small dome in the center. The intercalary band is rimlike around the cell margin, granulated and horizontally striated. Prorocentrum reticultum cells are oblong in valve view cells are 55-60 μm long and 40-45 μm wide .Thermal surface is reticulated it is composed of a labyrinth of ridges with alternating depressions that wavy in size and shape. Each depression has a narrow ablong kidney shaped opening about 0.6 μm long.The periflagellar area is a deep V-shaped trangle. The right valve of P reticulam is excavated and contains a large flagellar pore and a smaller auxi,iiary pore surrounded by a barrow optical collar.The left valve margin edhinits a curved flat ridge.The intercalary band is smooth. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive examination of the taxonomy of the genus Ostreopsis Schmidt. The morphology of six species of marine dinoflagellates, Ostreopsis siamensis Schmidt 1902, Ostreopsis lenticularies Fukuyo 1981, Osteropsis ovata Fukuyo 1981, Ostreopsis heptagona Norris, Bomber, et Balech 1985, Ostreopsis mascarenensis Quod 1994, from three geographical regions (Japan, Southwest Indian Ocean, and the Caribbean) and three marine habitats (sand, water column, and macroalgal surfaces) are described from scanning electron micrographs. Differences in the following morphological characteristics differentiated the species: cell shape and size, and ornamentation of the epitheca, cingulum, and hypotheca. The thecal plate formula of six Ostreopsis species is P[suba], 3',7", 6C, 6S?, V[subP], R[subP] 5"', 1P, 2"", with differences in thecal plate size and shape. The cingulum in ventral view has two prominent structures: a ventral plate (V[subp]) with a ventral pore (V[aubo]) and a ridged plate (R[subp]) that distinguishes Ostreopsis species from any other dinoflagellate taxa. This paper also includes ecological and toxicity information regarding the six Ostreopsis species. [ABSTRACT FROM AUTHOR]

The thecal surface morphology of Scrippsiella subsala (Ostenfeld) Steidinger et Balech was examined using the scanning electron microscope. This species is distinguished by a number of morphological characteristics. Aplcal plate 1' is wide, asymmetric, and pentagonal, and it ends at the anterior margin of the cingulum. Intercalary plates 2a and 3a are separated by apical plate 3'. The apical pore complex includes a large P[SUBa] plate with a raised dome at the center and a deep canal plate with thickened margin at plates 2', 3', and 4'. The intercalary bands are wide and deeply striated. The cingulum is deep, formed by six cingular plates; its surface is transversely striated and aligned with a row of minute pores. The cingular list continues around postcingular plate 1[SUPm] to form a sulcal list. The sulcal list is a flexible ribbon with a rounded tip that protrudes posterioly, partially covering the sulcal plates. The hypotheca is lobed, and the antapical plates are irregularly shaped and wide in antapical view: The thecal surface is vermiculate to reticulate. A comparison in morphology and ecology is presented between S. subsalsa and other known Scrippsiella species. [ABSTRACT FROM AUTHOR]

Dinoflagellate associations, including toxic and potentially toxic benthic species, were examined in sand from South Water Cay and Carrie Bow Cay, Belize. The inshore sand habitat in localized areas of warm shallow lagoonal waters supported blooms of toxic assemblages of dinoflagellates. In the sand, the dominant microalgae were dinoflagellates; cyanobacteria were a minor component and diatoms were absent. Ciliates and nematodes were present. Assemblages of microorganisms in colored sand were examined for 4 consecutive days after which a storm washed away the patch. The sand-dwelling dinoflagellate assemblage included 16 species where densities ranged from as low as 1.3% to 15% of total cell densities. The dominant species was Scrippsiella subsalsa, having 1.8 × 10[sup5] to 2.3 × 10[sup5] cells · g[sup-1 sand. Toxic dinoflagellates indentified in the sand were Gambierdicus toxicus, Ostreopsis lenticularis, Prorocentrum lima, Prorocentrum mexicanum, and Amphidinum carteri. The potentially toxic Ostreopsis labens, Gambierdiscus belizeanus sp. nov., and Coolia tropicalis sp. nov. were also identified. Toxic and potentially toxic species represented 36% to 60% of total microalgal cell assemblage. The morphology of a new sand-dwelling species, Gambierdiscus belizeanus sp. nov., was examined with the scanning electron microscope. The plate formula was P[subo], 3′, 7′′, 6c, 8s?, 5′′′, 1p, and 2′′′′. Dimensions of G. belizeanus cells were 53-67 μm long, 54-63 μm wide, and 92-98 μm in dorsoventral depth. Cells were deeply areolated, ellipsoid in apical view, and compressed anteroposteriorly. The cells of G. belizeanus were identified by the cell's long, narrow, pentagonal, posterior intercalary plate (1p) wedged between the wide postcingular plates 2′′′ and 4′′′; 1p occupied 20% of the width of the hypotheca. The plate formula for Coolia tropicalis sp. nov. was P[subo], 3′, 7′′, 7c, 8s?. 5′′′, and 2′′′′. Cell size ranges were 23-40 μm long, 25-39 μm wide, and 35-65 μm in dorsoventral diameter. Cells were spherical, smooth, and covered with scattered round pores. The epitheca was smaller than the hypotheca. Precingular plates 1′ and 7′′ were small and narrow, and the first apical plate 1′ and precingular plate 6′′ were the largest plates on the epitheca. The apical pore was straight and 7 μm long, and was situated in the apical plate complex. Cells of C. tropicalis were distinguished from C. monotis by the wedge-shaped plate 1′, a four-sided 3′ plate, and a short apical pore. [ABSTRACT FROM AUTHOR]

Three new benthic, sand-dwelling dinoflagellate species, Prorocentrum sabulosum, prorocentrum scuptile, and prorocentrum arenarium, from coral rubble are described from scanning electron micrographs. Species were identified based on shape, size, surface micromorphology, ornamentation of thecal plates, and architecture of the periflagellar area and intercalary band. Cells of P. sabulosum are oval with a cell size of 48-50 μm long and 41-48 μm wide. The areolae are round to oval and numerous (332-450 per valve) and range from 1 to 1.6 μm in size. The periflagellar area of P. sabulosum bears a wide V-shaped depression with a flat ridge and lacks ornamentation; it accommodates six pores: one large flagellar pore, an adjacent smaller auxiliary pore, and four pores of unknown function. The flagellar and auxiliary pores are surrounded by a narrow apical collar. The intercalary band of P. sabulosum is smooth. Prorocentrum sculptile cells are broadly oval, 32-37 μm long, and 30-32 μm wide in valve view with a deep-sculptured apical area. The valves are smooth and are marked with shallow depressions (856-975) per valve). Some of these depressions have a small round opening (0.13 μm in diameter). The periflagellar area is V0shaped with a deeply indented depression; it accommodates the two flagella and a thin angled apical plate. The intercalary band is smooth. Prorocentrum arenarium cells are nearly round in valve view 30-32 μm in diameter. Thecal surface is smooth with scattered kidney-shaped valve poroids (65-73 per valve) and marginal poroids (50-57 per valve). Length and width of poroids are 0.62 μm and 0.36 μm, respectively. The periflagellar area is an unornamented, broad triangle into which a large flagellar pore and a smaller auxiliary pore are fitted. Both flagella, longitudinal and transverse, protrude from the flagellar pore. The intercalary band is smooth. The presence of a peduncle-like structure (2-3 μm long) in P. arenarium was observed situated in the flagellar pore. [ABSTRACT FROM AUTHOR]

This study indicates that bilaterally flattened, armored, benthic dinoflagellates are more diverse in morphology than previously known. A new species, Plagiodinium belizeanum Faust et Balech gen. et sp. nov., is described in floating detritus from Twin Cays, Belize, mangrove habitats. Plagiodinium belizeanum cells are small, with dimensions of 26.5-30.5 μm in length, 20-24.5 ???m in width, and 6.5-8.5 μm in depth. Cells are ablong and bilaterally compressed with a posteriorly located, spherical nucleus, many chloroplasts, and spherical starch granules. The epitheca descends ventrally, is cap-shaped, and is composed of five plates and a very small platelet provisionally named P??? situated in the center. The epitheca is narrowly oval in opical view with a pointed truncated ventral side and a rounded dorsal side. The cingulum is composed of five plates. The hypotheca is constructed of five posteriorly elongated postcingular plates and one antapical plate. The sulcus is very short and narrow, comprised of five small plates. The thecal plate arrangement of P. belizeanum is P[SUB0] 5', O′, 5C, 1′′, 5S. No lists are present. Thecal plates have a smooth surface with small and irregularly scattered pores. The intercalary bond is smooth on the outer cell surface and broadly striated on its inner surface. We conclude that P. belizeanum represents a new, benthic, peridinioid, armored genus, Plagiodinium gen. nov. The taxonomic position of P. belizeanum sp. nov. is compared to related sand-dwelling and bilaterally flattened benthic dinoflagellates [ABSTRACT FROM AUTHOR]

Three new benthic dinoflagellate species. Prorocentrum belizeanum, Prorocentrum elegans, and Pro-rocentrum caribbaeum, from mangrove floating detritus are described from scanning electron micrographs. Species were identified based on shape, size, surface micromorphology, ornamentation of thecal plates, and architecture of the periflagellar area and intercalary band. Cells of P. belizeanum are round to slightly oval with a cell site o.[55-60 urn long and 50-55 μ wide. Areolae are round and numerous (855-1024 per valve)and range from 0.66 to 0.83 μm in site. The periflagellar area of P. belizeanum is a broad V-shaped depression; it accommodates a flagellar and an auxiliary pore and a flared, curved apical collar. The intercalary band of P. belizeahum is horizontally striated. Prorocentrum elegans is a small species 15-20 μmlong and 10-14 μm wide, with an ovate cell shape. The thecal surface is smooth. Two sites of value pores were recognized: large, round pores (20-22 per valve) arranged in a distinct pattern and smaller pores situated in an array along the intercalary band. The periflagellar area is V-shaped; it accommodates an uneven sited flagellar pore, an auxiliary pore, and an angled protuberant flagellar plate. The intercalary band is transversely striated. It is a bloom.forming species. Prorocentrum caribbaeum cells are heart-shaped with a rounded anterior end and a pointed posterior end. Cells range from 40 to 45 tun long and 30 to 35 μm wide. Thecal surface has two different-sized pores: large, round pores (145-203 per valve) arranged perpendicularly from the posterior margins, and small, round pores unevenly distributed on the thecal surface. The periflagellar area is ornate. It is V. shaped with a curved apical collar located next to the auxiliary pore; a smaller protuberant apical plate is adjacent to the flagellar pore. The intercalary band is transversely striated and sinuous. Cells are active swimmers. [ABSTRACT FROM AUTHOR]

Compares the surface morphology of the dinoflagellate Coolia monotis Meunier with the surface morphology of Ostreopsis. Similarity of the architecture of the apical pore of C. monotis to that of Ostreopsis; Location of a ventral pore in C. monotis on the right ventral margin before aplical plate 1' and precingular plate 6"; Asexual reproduction.

Two new dinoflagellate species, Prorocentrum hoffmannianum and Prorocentrum ruetzlerianum, and four known species, Prorocentrum emarginatum Fukuyo 1981, Prorocentrum mexicanum Tafall 1942, Prorocentrum concavum Fukuyo 1981, and Prorocentrum lima (Her.) Dodge 1975, from floating detritus and sediments in a subtropical mangrove island, Twin Cays, Belize, Central America are described from scanning electron micrographs. Differences in the following characters of surface micromorphology separated the species: ornamentation of thecal plates (shape, size, and number of valve pores and areolae) and the architecture of the periflagellar area and intercalary band. [ABSTRACT FROM AUTHOR]

Studies growth and pigment concentrations of the estuarine dinoflagellate, Prorocentrum mariae-lebouriae in cultures grown in white, blue and red radiation at three different irradiances. Photon flyx densities; Clorophyll concentrations.

The surface structures of the bivalvate dinoflagellate Prorocentrum mariae-lebouriae are described in detail it has an almost spheroidal shape in face view, a compressed saucer-shape in side view, with a distinct striated band at the edge of the cell. Its surface is covered with small spines in a regular pattern, with 450 nm distance between pairs. The spines are 100-120 nm wide and 200-300 nm long. There are 600-700 spines on each valve. At the anterior cell end, one of the valves has a V-shaped depression which contains a specialized structure accommodating the 2 flagellar pores. The flagellar pores are enclosed by 8 small, thick plates held together and to the valves by sutures. The flagellar pore area consists of 2 distinct structures: an apical collar possessing a curved forked plate and a larger structure composed of an unbranched plate. There are 2 flagellar canals located between the flagellar pore plates. Beneath each flagellar canal lies a row of 11 microtubules. A row of microtubules forming a microtubular cylinder is situated adjacent to the oblong flagellar canal near a sample pusule. The microtubular cylinder encircles electron dense bodies. The bases of the longitudinal and transverse flagella appear to lie at an angle to each other. The above features are illustrated with transmission and scanning electron micrographs. [ABSTRACT FROM AUTHOR]

Abstract: Dinoflagellates in the genus Gambierdiscus produce toxins that bioaccumulate in tropical and sub-tropical fishes causing ciguatera fish poisoning (CFP). Little is known about the diversity and distribution of Gambierdiscus species, the degree to which individual species vary in toxicity, and the role each plays in causing CFP. This paper presents the first global distribution of Gambierdiscus species. Phylogenetic analyses of the existing isolates indicate that five species are endemic to the Atlantic (including the Caribbean/West Indies and Gulf of Mexico), five are endemic to the tropical Pacific, and that two species, Gambierdiscus carpenteri and Gambierdiscus caribaeus are globally distributed. The differences in Gambierdiscus species composition in the Atlantic and Pacific correlated with structural differences in the ciguatoxins reported from Atlantic and Pacific fish. This correlation supports the hypothesis that Gambierdiscus species in each region produce different toxin suites. A literature survey indicated a >100-fold variation in toxicity among species compared with a 2 to 9-fold within species variation due to changing growth conditions. These observations suggest that CFP events are driven more by inherent differences in species toxicity than by environmental modulation. How variations in species toxicity may affect the development of an early warning system for CFP is discussed. [ABSTRACT FROM AUTHOR]