ULTRASTRUCTURE OF A NEW SAND-DWELLING DINOFLAGELLATE,SCRIPPSIELLA ARENICOLA SP. NOV1

A new dinoflagellate, Scrippsiella arenicola Horiguchi et Pienaar sp. nov., is described from tidal pools with sandy substrates along the east coast of South Africa. S. arenicola exhibits a vertical migratory rhythm which is in synchrony with the tidal cycle. It is a medium-sized armoured dinoflagellate with many rod-shaped chloroplasts. Thecal plate arrangement is pp, x, 4′, 3a, 7′, 6c, 5′, 2″ and 4s. The 2a and 3a plates are separated from each other. S. arenicola has several unique ultrastructural features. Electron-dense fibres are found on the protruded part of the thecal plates, such as on the ornamental projections or extremities of the lists. In addition to the 9 + 2 axoneme, additional fibres are found in the free moving part of the longitudinal flagellum. The portion of the transverse flagellum covered by the left sulcal list possesses a dense array of mastigonemes which connect the flagellum and the cell. The flagellar pore platelets differ from ordinary thecal plates in their thickness and fibrous nature. The ultrastructure of the apical stalk and its associated structures is described. The vertical migration and mode of cell division is also described.     

AMPHIDINIUM CRYOPHILUM SP. NOV. (DINOPHYCEAE) A NEW FRESHWATER DINOFLAGELLATE. I. SPECIES DESCRIPTION USING LIGHT AND SCANNING ELECTRON MICROSCOPY1

Amphidinium cryophilum sp. nov. was found in the fall of 1979 in a small pond near Madison, Wisconsin. During the ensuing winter, it became the dominant phytoplankter. Cell numbers remained high despite a thick layer of ice and snow. After the ice melted in the spring the organism disappeared from plankton samples. A successful culture of A. cryophilum was established only when isolates were incubated at 5–7° C. It is compared with two morphologically similar species, A. amphidinioides (Geitler) Schiller and Gymnodinium inversum Nygaard. Amphidinium cryophilum is distinguished from the former by its pigmentation (golden-yellow vs. blue-green), the location of the cingulum, and its lack of an eyespot. It differs from the latter in cell shape, the route of the sulcus and position of the nucleus.     

CACHONINA ILLDEFINA SP. NOV. (DINOPHYCEAE): CHLOROPLAST TUBULES AND DEGENERATION OF THE PYRENOID1

A new species of the dinoflagellate genus Cachonina, C. illdefina sp. nov., was isolated from a red tide off El Capitan State Park, Santa Barbara County, California, in October 1973. The organism is light yellowgreen in color with deeply incised girdle and sulcal grooves. Electron microscopy of the organism, revealed a typical dinokaryotic nucleus. The chloroplasts of the organism are connected, and often contain microtubule-like elements, 25 nm diam. The pyrenoids are characterized as excluding chloroplast thylakoids and ribosomes, although containing an amorphous matrix and numerous tubular invaginations from the cytoplasm. The pyrenoids become detached from the chloroplasts and degenerate into small vesicles. C. illdefina is not bioluminescent.     

PFIESTERIA PISCICIDA GEN. ET SP. NOV. (PFIESTERIACEAE FAM. NOV.), A NEW TOXIC DINOFLAGELLATE WITH A COMPLEX LIFE CYCLE AND BEHAVIOR1

The newly described toxic dinoflagellate Pfiesteria piscicida is a polymorphic and multiphasic species with flagellated, amoeboid, and cyst stages. The species is structurally a heterotroph; however, the flagellated stages can have cleptochloroplasts in large food vacuoles and can temporarily function as mixotrophs. The flagellated stage has a typical mesokaryotic nucleus, and the theca is composed of four membranes, two of which are vesicular and contain thin plates arranged in a Kofoidian series of Po, cp, X, 4′, 1a, 5″, 6c, 4s, 5″′, and 2″″. The plate tabulation is unlike that of any other armored dinoflagellate. Nodules often demark the suture lines underneath the outer membrane, but fixation protocols can influence the detection of plates. Amoeboid benthic stages can be filose to lobose, are thecate, and have a reticulate or spiculate appearance. Amoeboid stages have a eukaryotic nuclear profile and are phagocytic. Cyst stages include a small spherical stage with a honeycomb, reticulate surface and possibly another stage that is elongate and oval to spherical with chrysophyte-like scales that can have long bracts. The species is placed in a new family, Pfiesteriaceae, and the order Dinamoebales is emended.     

MORPHOLOGY AND MOLECULAR ANALYSES OF THREE TOXIC SPECIES OF GAMBIERDISCUS (DINOPHYCEAE): G. PACIFICUS, SP. NOV., G. AUSTRALES, SP. NOV., AND G. POLYNESIENSIS, SP. NOV.

Three new dinoflagellate species, Gambierdiscus polynesiensis, sp. nov., Gambierdiscus australes, sp. nov., and Gambierdiscus pacificus, sp. nov., are described from scanning electron micrographs. The morphology of the three new Gambierdiscus species is compared with the type species Gambierdiscus toxicus Adachi et Fukuyo 1979, and two other species: Gambierdiscus belizeanus Faust 1995 and Gambierdiscus yasumotoi Holmes 1998. The plate formula is: Po, 3′, 7", 6C, 8S, 5‴, 1p, 2". Culture extracts of these three new species displayed both ciguatoxin- and maitotoxin-like toxicities. The following morphological characteristics differentiated each species. 1) Cells of G. polynesiensis are 68–85 μm long and 64–75 μm wide, and the cell’s surface is smooth. They are identified by a large triangular apical pore plate (Po), a narrow fish-hook opening surrounded by 38 round pores, and a large, broad posterior intercalary plate (1p) wedged between narrow postcingular plates 2‴ and 4‴. Plate 1p occupies 60% of the width of the hypotheca. 2) Cells of G. australes also have a smooth surface and are 76–93 μm long and 65–85 μm wide in dorsoventral depth. They are identified by the broad ellipsoid apical pore plate (Po) surrounded by 31 round pores and a long and narrow 1p plate wedged between postcingular plates 2‴ and 4‴. Plate 1p occupies 30% of the width of the hypotheca. 3) Cells of G. pacificus are 67–77 μm long and 60–76 μm wide in dorsoventral depth, and its surface is smooth. They are identified by the four-sided apical pore plate (Po) surrounded by 30 round pores. A short narrow 1p plate is wedged between the wide postcingular plates 2‴ and 4‴. Plate 1p occupies 20% of the width of the hypotheca. These three newly described species were also characterized by isozyme electrophoresis and DNA sequencing of the D8–D10 region of their large subunit (LSU) rRNA genes. The consistency between species designations based on SEM microscopy and classification inferred from biochemical and genetic heterogeneities was examined among seven isolates of Gambierdiscus. Their classification into four morphospecies was not consistent with groupings inferred from isozyme patterns. Three molecular types could be distinguished based on the comparison of their LSU rDNA sequences. Although G. toxicus TUR was found to be more closely related to G. pacificus, sp. nov. than to other G. toxicus strains, the molecular classification was able to discriminate G. polynesiensis, sp. nov. and G. australes, sp. nov. from G. toxicus. These results suggest the usefulness of the D8–D10 portion of the Gambierdiscus LSU rDNA as a valuable taxonomic marker.     

DEGRADATION OF THE CELL-WALL POLYSACCHARIDE OF PORPHYRIDIUM SP. (RHODOPHYTA) BY MEANS OF ENZYMATIC ACTIVITY OF ITS PREDATOR,GYMNODINIUM SP. (PYRROPHYTA)1

The dinoflagellate Gymnodinium sp., which preys specifically on cells of the red microalga Porphyridium sp., possesses enzymes that degrade exocellular polysaccharides of the Porphyridium sp. A crude extract of Gymnodinium sp. was applied to this polysaccharide, and the degradation products were characterized by charge and size separations. Charge separation revealed the presence of a fraction that was not found in the native polysaccharide. This fraction, which was eluted from an anion-exchange resin with water alone, was composed mostly of glucose and xylose (in a 1:1 weight ratio). Size separation of the degradation products revealed three fractions; the molecular weight of the main one was 5 × 10⁶ daltons, whereas that of the native polysaccharide was 7 × 10⁶ daltons. The carbohydrate composition of these fractions was determined. Although the main product of degradation had a relatively high molecular weight, its viscosity was significantly reduced relative to the native polysaccharide. Additional enzymatic degradation is required for further exploration of the structure of the exocellular polymer of Porphyridium sp.     

THE FINE STRUCTURE AND SCALE FORMATION OF CHRYSOLEPIDOMONAS DENDROLEPIDOTA GEN. ET. SP. NOV.(CHRYSOLEPIDOMONADACEAE FAM. NOV., CHRYSOPHYCEAE)1

Chrysolepidomonas gen. nov. is described for single-celled monads with two flagella, a single chloroplast, and distinctive canistrate and dendritic scales. The type species, Chrysolepidomonas dendrolepidota sp. nov., is described for the first time. The canistrate scales bear eight “bumps” on the top surface, and the dendriticscales have a tapered base with a quatrifid tip. These organic scales are formed in the Golgi apparatus and storred in a scale reservoir. The scale reservoir is bounded on two sides by the R₁ and R₂ in microtubular roots of the basal apparatus. The cyst (=stomatocyst, statospore) forms endogenously by means of a silica deposition vesicle. The outer cyst surface is smooth, and the pore region is unornamented. Two other organisms bearing canistrate and dendritic scales, previously assigned to the genus Sphaleromants, are transferred to the genus Chrysolepidomonas. They are C.angalica sp. nov. and C. marine(Pienaar) comb. nov. The distinguishing features of Chrysolepidomonas and Sphaleromantis are discussed. A new family, Chrysolepidomonadceae fam. noc., is described for flagellates covered with organic scales.     

ULTRASTRUCTURE AND 18S RRNA GENE SEQUENCE FOR PELAGOMONAS CALCEOLATA GEN. ET SP. NOV. AND THE DESCRIPTION OF A NEW ALGAL CLASS,THE PELAGOPHYCEAE CLASSIS NOV.1

Pelagomonas calceolata gen. et sp. nov., an ultra-planktonic marine alga, is described using electron microscopy and the cytoplasmic small subunit (18S) ribosomal RNA (rRNA) gene sequence. Cells are uniflagellate, about 1.5 × 3 μm in size. The flagellium has two rows of bipartite hairs, the paraxonemal rod has a dentate appearance, and a two-gyred transitional helix is present between two transitional plates. Microtubular roots, striated roots, and a second basal body are absent. A thin organic theca surrounds most of the cell. There is a single chloroplast with a girdle lamella and a single, dense mitochondrion with tubular cristae. A single Golgi body with swelled cisternae lies beneath the flagellum, and each cell has an ejectile organelle that putatwely releases a cylindrical structure. A vacuole, or cluster of vacuoles, contains the putative carbohydrate storage product. The 18S rRNA gene was sequenced completely in both directions, excluding three primer regions. When compared to the same gene sequence from other organisms, Pelagomonas calceolata gen. et sp. nov. occupies an unresolved position among other chromophyte algae and is distinct from members of any of these classes. Based on morphological, ultrastructural, and molecular data, we describe this alga as a new species, and we place this highly unusual new species in a new genus, family, order, and class.     

THE GENUS HYPOGLOSSUM KÜTZING (DELESSERIACEAE,RHODOPHYTA) IN THE TROPICAL WESTERN ATLANTIC,INCLUDING H. ANOMALUM SP. NOV.1

Observations are made on the occurrence and distribution of the red algal genus Hypoglossum Kützing (Delesseriaceae, Ceramiales) in the tropical western Atlantic. In addition to the type of the genus, H. hypoglossoides (Stackh.) Coll. & Herv., three other species are reported: H. anomalum sp. nov., H. involvens (Harv.) J. Ag., and H. tenuifolium (Harv.) J. Ag. A key is presented to distinguish these four species. The newly described species, H. anomalum, is like other species in the genus in that its branches arise endogenously from the primary axial row but it is unique in that the branches emerge from the parent blade at some point between the midline and the margin of the blade. The new species is reported from Puerto Rico and Florida.     

THE ULTRASTRUCTURE OF PYRAMIMONAS PSEUDOPARKEAE SP. NOV. (PRASINOPHYCEAE) FROM SOUTH AFRICA1

The ultrastructure of Pyramimonas pseudoparkeae sp. nov., a member of the class Prasinophyceae occurring in tidal pools along the east, south and west coast of South Africa, is described. The cell surface is covered by three distinctive body scales whilst the flagellar surfaces possess four types of scales. The structure of these scales is described. P. pseudoparkeae resembles Pyramimonas parkeae Norris and Pearson but differs in the structure of the type 2 body scale. The symmetry and ultrastructure of the cell are described with special attention given to the flagellar apparatus. Preliminary information on the life cycle of this species is presented. This new species is compared with other closely related members of the genus Pyramimonas.     

STARRIA ZIMBABWEËNSIS (CYANOPHYCEAE) GEN. NOV. ET SP. NOV.: A FILAMENT TRIRADIATE IN TRANVERSE SECTION1

A new filamentous bluegreen alga Starria zimbabweënsis gen. nov. et sp. nov. isolated from a soil sample collected near Zimbabwe, Southern Rhodesia, has a unique triradiate morphology. In transverse section each narrow cell possesses three arm-like projections, separated by 120° and in which pigment is concentrated. Filaments may be straight or twisted and various clonable biradiate forms have originated in cultures initiated from the triradiate type. Cell ultra-structure is typical of the Oscillatoriaceae except that 70 nm pit-like pores occur throughout the L-II layer of the longitudinal walls. Wall structure of deviant forms is identical to that of the triradiate “wild type.” The organism is assigned to the Oscillatoriaceae rather than to the Gomontiellaceae or to a new family.     

THE GENUS PLATOMA (GIGARTINALES,RHODOPHYTA) WITH A DESCRIPTION OF P. ABBOTTIANA SP. NOV.1

Platoma abbottiana (Gymnophlaeaceae; Gigartinales), a new species of benthic red algae, is described from Isla Mejía and is the second member of this genus reported from the Gulf of California, Mexico. Vegetative anatomy and reproductive details of the carpogonial and auxiliary cell branches of the new species are described and illustrated. Geographical distributions of the seven previously described Platoma species are given. Their distinguishing morphological characteristics are compared to those of the new species. The correct time and place of valid publication of the generic name, Platoma, and some of its binomials are discussed.     

LIGHT AND ELECTRON MICROSCOPY OF A PUNCTATE SPECIES OF PYRAMIMONAS,P. MUCIFERA SP. NOV. (PRASINOPHYCEAE)1

Pyramimonas mucifera sp. nov., a punctate species of the genus, is unusual both behaviorally and at the fine structural level. It forms two distinct populations in culture, one benthic and one planktonic. Planktonic forms are more conventional for the genus, but benthic forms are found in loosely packed mucilage, have flagellar rather than ciliary beating of the flagella, and display a higher degree of metaboly. Ultrastructurally this species is unusual in that it has a unique scale complement and the cells contain numerous muciferous vesicles, leaving only small pockets of cytoplasm containing the usual organelles. This species has a 3–1 type flagellar apparatus but has an additional fibrillar band, a 4–3-2–3 microtubular root system and a flexible synistosome. The discovery of a mucilage-producing species of Pyramimonas draws attention to possible links with other prasinophytes (Halosphaera) and green algae of questionable affiliation (Oltmannsiellopsis and Hafniomonas). It also provides a model of the primitive pyramimonad.     

ATRACTOMORPHA PORCATA SP. NOV., A NEW MEMBER OF THE SPHAEROPLEACEAE (CHLOROPHYCEAE) FROM CALIFORNIA1

Atractomorpha porcata sp. nov. is described from culture isolates derived in 1981 from zygotes present in a 28 year old, dried soil sample collected from near Lemon-cove, Tulare County, California. Vegetative individuals are coenocytic, spindle-shaped unicells with long, thin-pointed apices. Asexual reproduction is by means of large, biflagellate zoospores or, frequently, by aplanospores. Sexual reproduction is usually monoecious, with a single spindle-shaped gametangial cell producing small, biflagellate male gametes at either end, and larger female gametes in the midportion. Female gametes are often biflagellate, but more commonly they lack flagella and are liberated by squeezing through slit-like openings in the gametangial wall. Sexual reproduction may thus be considered as either oogamous or anisogamous, depending on whether or not a particular female gamete has flagella; most often it is oogamous. Atractomorpha porcata is readily distinguished from A. echinata, the only other known member of the genus, by (1) its greater tendency toward oogamy (versus anisogamy), (2) its bisexual gametangia, (3) its frequent production of aplanospores in asexual reproduction, (4) its unusual primary membranes that frequently bear long, delicate bristles, and (5) its distinctive zygote wall ornamentation.     

CHRYSOCHROMULINA BREVITURRITA SP. NOV., A NEW FRESHWATER MEMBER OF THE PRYMNESIOPHYCEAE1

Chrysochromulina breviturrita sp. nov. is described as a new haptonema-bearing member of the freshwater Prymnesiophyceae. It is ca. three times larger than the only other known freshwater member of the genus (C. parva Lackey)and possesses a haptonema only ca. 0.2–0.3 as long as the haptonema of C. parva. Two equal flagella (1.5–2 as long as the haptonema), a large contractile vacuole, two parietal plasties, a single pyremid, nucleus, Chrysolaminarin-like droplets and a food vacuole are features readily observed with the light microscope. Dried and shadoweast whole mounts examined with the electron microscope reveal the cell surface covered with two types of small, delicate scales: outer spined scales with a clubshaped terminus and with the spine anchored to a circular to oval base-plate by 2–6 (7) branching arms; and, spineles oval plate scales with concentric lines and radiating ridges on one face and parallel ridges on the other. C. breviturrita has been found in nine lakes in Ontario (Canada). Pereliminary observations suggest that it is an important component of lake plankton and has probably not been delected in previous work, more because of its fragility than because of its scarcity. Living specimens are a prerequisite for initial identification, since cells frequently rupture and haptonemata are often lost when the organisms are killed with the commonly used fixatives.     

MORPHOLOGY OF THE SUBANTARCTIC RED ALGA CENACRUM SUBSUTUM GEN. ET SP. NOV. (RHODYMENIALES) FROM MACQUARIE ISLAND1

The red alga Cenacrum subsutum gen. et sp. nov. is described from material collected at Macquarie Island in the subantarctic between November 1977 and February 1978. The habit and carposporophyte development are similar to members of the family Rhodymeniaceae (Rhodymeniales), but certain vegetative features are unique. The frond is a variously incised or lobed foliose blade with hollow apices above and a medulla which becomes progressively filled basipetally with ingrowing rhizoidal filaments. Details of carpogonial branch, auxiliary cell, connecting cell and gonimoblast anatomy are given, as well as observations on the habitats and distribution of the species.     

NORTH CAROLINA MARINE ALGAE. IX. ONSLOWIA ENDOPHYTICA GEN. ET SP. NOV. (PHAEOPHYTA,SPHACELARIALES) AND NOTES ON OTHER NEW RECORDS FOR NORTH CAROLINA1

Four benthic algae are reported here for the first time in the North Carolina flora. The new brown algal genus and species, Onslowia endophytica Searles, is described as an endophyte of Halymenia floridana from the North Carolina continental shelf. New records of Boodleopsis pusilla and Naccaria corymbosa from North Carolina constitute range extensions of these tropical species on the American coast north from Florida. Blastophysa rhizopus, an endophyte and epiphyte known from the North Atlantic coast of Europe and America as well as the Caribbean is reported from North Carolina for the first time and in a new host, Predaea feldmannii.     

THE PHYLOGENETIC RELATIONSHIP OF PFIESTERIA PISCICIDA, CRYPTOPERIDINIOPSOID SP. AMYLOODINOUM OCELLATUM AND A PFIESTERIA-LIKE DINOFLAGELLATE TO OTHER DINOFLAGELLATES AND APICOMPLEXANS

The taxonomic relationship between heterotrophic and parasitic dinoflagellates has not been studied extensively at the molecular level. In order to investigate these taxonomic relationships, we sequenced the small subunit (SSU) ribosomal RNA gene of Pfiesteria piscicida (Steidinger et Burkholder), a Pfiesteria -like dinoflagellate, Cryptoperidiniopsoid sp., and Amyloodinium ocellatum (Brown) and submitted those sequences to GenBank. Pfiesteria piscicida and Cryptoperidiniopsoid sp. are heterotrophic dinoflagellates, purportedly pathogenic to fish, and A. ocellatum, a major fish pathogen, has caused extensive economic losses in both the aquarium and aquaculture industries. The pathogenicity of the Pfiesteria -like dinoflagellate is unknown at this time, but its growth characteristics and in vitro food preferences are similar to those of P. piscicda. The SSU sequences of these species were aligned with the other full-length dinoflagellate sequences, as well as those of representative apicomplexans and Perkinsus species, the groups most closely related to dinoflagellates. Phylogenetic analyses indicate that Cryptoperidiniopsoid sp., P. piscicida, and the Pfiesteria -like dinoflagellate are closely related and group into the class Blastodiniphyceae, as does A. ocellatum. None of the species examined were closely related to the apicomplexans or to Perkinsus marinus, the parasite that causes "Dermo disease" in oysters. The overall phylogenetic analyses largely supported the current class and subclass groupings within the dinoflagellates.