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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]

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]

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]

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]

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]