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Diplotheca costata Valkanov, 1970. The lorica is composed of two quite distinct chambers. The anterior chamber contains 18 longitudinal costae, each being formed by two costal strips with spatulate ends. A transverse costa containing six flattened costal strips forms the anterior ring and another composed of crescentic strips marks the boundary between the two chambers. The posterior chamber contains 10 broad and flattened costal strips with rounded ends. Each strip has a more opaque central region, on either side of which is a thinner region bearing a row of narrow transverse markings.
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Acanthoeca spectabilis Ellis, 1930. Cells are 3.5-5 microns in length, elongate with a pointed posterior, and fit closely to the main chamber of the lorica. Electron microscopy reveals that these cells are enclosed by fibrous material. The pseudopodial collar is shorter than the cell and the flagellum projects slightly from the top of the lorica. The main chamber of the lorica is conical and tapers posteriorly, giving rise to a pedicel. Costae in the main chamber give rise to longitudinal spines anteriorly. Fibres were present and arranged in the same pattern as costal strips in normal cells, except that, being less rigid, the spines are irregular and crumpled. The conical shape of the main chamber and the pedicel appears to be maintained by a membranous structure in the cells with a fibrous lorica.
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Diaphanoeca fiordensis (Scagel and Stein, 1961) Norris, 1965. Choanoflagellates with a hyaline ribbed lorica, said by some to have a faintly pigmented pale green portion ovoid, 5 microns wide by 8 microns long, single flagellum 15-17 microns long. Enclosed in transparent, slightly flattened, basket-like lorica 16 microns wide by 24 microns long (including spines), lorica invaginated where flagellum emerges, tapering to a point opposite closed end. The lorica usually ornamented with three peripheral ridges transverse to longitudinal axis, and 10 emergent longitudinal ridges that merge at closed end but extend freely a distance of 10 microns to form a fringe of spines beyond open end.
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Calliacantha natans (Groentved, 1956) Leadbeater, 1978. Choanoflagellates with a conical lorica, 25 - 27 microns long and with six longitudinal and two transverse costae. One transverse costa is located at the top of the lorica chamber, the other is shortly below it, but is formed of thinner costal strips and may be difficult to see. Three spines project from the top of the lorica and a single posterior spine. The anterior spines are not continuous with the longitudinal costae.
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Calliacantha longicaudata (Leadbeater, 1975) Leadbeater, 1978. Choanoflagellates, lorica of which consists of a single chamber, 15-17 microns long x 6-8 microns wide, composed: of 5 (sometimes locally 4 or 6) longitudinal costae, each of 2 linearly attached slender cylindrical costal strips overlapping where they join, delimited anteriorly by 2 transverse costae, one terminal and the other parallel to it at about one sixth I of the length of the chamber behind it, transverse costal strips of both rings joined by their ends to the subtending longitudinal costae, at the posterior end, the longitudinal costae converging to subtend a caudal appendage of exceptional length (up to 100 microns) composed of up to 13 linearly attached costal strips overlapping at their ends and becoming thinner distally. The cell is enclosed by a conical membrane within the lorica chamber, attached to its base and equalling it in length, width when full 3-5 microns, the single flagellum exceeding 20 microns in length, surrounded by a ring of about 40 tentacles up to 6 microns in length, sometimes with terminal swellings.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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Crinolina isefiordensis Thomsen, 1981. Cell solitary, planktonic, living in skirt-shaped lorica, open anteriorly and posteriorly. Protoplast 8 microns long and 5 microns wide, without chloroplast. Single flagellum 2-3 times protoplast length, surrounded by a collar of tentacles. Height of collar approximately 6 microns, maximum diameter of collar 13 microns Lorica 25-30 microns long, diameter at base 20-30 microns, diameter at neck constriction 10-13 microns Longitudinal costae (12) 15-16, each composed of 6-7 costal strips. Two transverse costae. Longitudinal costae form spines at the anterior end of the lorica. Each spine is composed of two costal strips. Posteriorly the longitudinal costae project slightly beyond the transverse costal ring.
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Diaphanoeca grandis Ellis, 1930. Choanoflagellates with a lorica composed of 12-14 longitudinal costae each formed by 7-8 strips of equal length. Three transverse rings encircle the base of the lorica and one ring, consisting of paired strips, encircles the longitudinal costae towards the anterior end. The protoplast, which is situated centrally within the lorica, bears an anterior collar of tentacles and a single flagellum. Accumulations of detached strips are frequently found at either end of the cell within the lorica. These strips are equal in length to those forming the costae.
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Diaphanoeca grandis minor Throndsen, 1974. Similar to Diaphanoeca grandis but lorica length 18-22 microns, lorica diameter 15 microns Number of longitudinal costae 10.
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Diaphanoeca pedicellata Leadbeater 1972 (also referred to as Campanoeca pedicellata (Leadbeater, 1972) Throndsen, 1974). The subspherical protoplast (4-5 microns long, 4-5 microns wide) bears an anterior ring of 20-30 tentacles. The funnel-shaped lorica chamber is formed by 20-30 longitudinal costae (about 10 microns long) which at the upper end project as spines beyond the anterior transverse costa. The lorica is 45 microns high consisting of one chamber formed by about 14 longitudinal costae and three transverse costae(one towards the anterior end of the lorica, one just below the mid-lorica region, and one towards the posterior end of the lorica chamber). Posteriorly about seven longitudinal costae converge and join with a posterior stalk (about 11 microns long) formed by at least two or three costal strips attached end-to-end. All the costal strips forming the lorica are approximately equal in length and width.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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This image was made from samples taken during a scientific cruise in the Pacific. Water was filtered to concentrate the organisms that were present, then dried onto a thin sheet of plastic and then shadowed with a fine layer of metal to provide contrast. The preparation was then observed with an electron-microscope. This technique has been used to document the diversity of marine microbes, especially, protists in the oceans.
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Pleurasiga minima Throndsen, 1970. Lorica 9.5-16 microns long with 2 transverse costae and 7 longitudinal costae, all of which extend to the posterior of the lorica. The transverse costae are of about the same width, and the lorica narrows below the second costa to form a pointed base. Cell located at the posterior of the lorica, with flagellum protruding above it.
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Pleurasiga minima minima Throndsen, 1970. The different varieties differ mainly in size. The lorica of P. minima minima is about 10 microns long and wide.
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Pleurasiga reynoldsii Throndsen, 1970. The lorica is 23 microns long and 22 microns wide, respectively.
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Polyoeca dichotoma Kent, 1880. Lorica of polythecium urceolate, pedicellate, tapering posterioly, slightly constricted at a distance of one-third of the total length from the anterior margin, and then widening out to their greatest diameter, pediceles of each separate lorica straight, slender, varying from the same to two or three times the length of the latter structure, contained animalcules ovate, occupying respectively about one-half of the cavities of the lorica, contour of polythecium subdichotomous, each zooid usually giving rise by trasverse fission to two new ones which attach themselves to opposite sides of the parent lorica. Length of separate lorica 10 microns
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Portrait of the acanthoecid choanoflagellate, Polyoeca dichotoma (Kent, 1881). Cells are solitary or united to form linear or dendroid colonies which attach to the substrate. The lorica is funnel-shaped, constructed of numerous siliceous longitudinal costae, each made up of costal strips. The longitudinal costae terminate as anterior spines (11-17); 2 or more bands of equally spaced transverse costal strips (difficult to see in vivo) encircle the lorica chamber in which the protoplast (cell body) resides. At the apex of the funnel the longitudinal costae unite to form an aggregated pedicel. In dendroid colonies the pedicel of the daughter (anterior) cell attaches to the outside of the lorica of the parent cell. Details of lorica morphology are best seen with scanning electron microscopy. The cell body has one anterior flagellum (seen here) surrounded by a rhizopodial collar (not visible here). Division is nudiform (i.e. naked swarmers are formed which then form a lorica). Collected from a commercial saltwater aquarium in Boise, Idaho February 2004. DIC.
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Portrait of the acanthoecid choanoflagellate, Polyoeca dichotoma (Kent, 1881). Cells are solitary or united to form linear or dendroid colonies which attach to the substrate. The lorica is funnel-shaped, constructed of numerous siliceous longitudinal costae, each made up of costal strips. The longitudinal costae terminate as anterior spines (11-17); 2 or more bands of equally spaced transverse costal strips (difficult to see in vivo) encircle the lorica chamber in which the protoplast (cell body) resides. At the apex of the funnel the longitudinal costae unite to form an aggregated pedicel. In dendroid colonies the pedicel of the daughter (anterior) cell attaches to the outside of the lorica of the parent cell. Details of lorica morphology are best seen with scanning electron microscopy. The cell body has one anterior flagellum (seen here) surrounded by a rhizopodial collar (not visible here). Division is nudiform (i.e. naked swarmers are formed which then form a lorica). Collected from a commercial saltwater aquarium in Boise, Idaho February 2004. DIC.
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Savillea micropora (Norris, 1965) Leadbeater, 1975. Cells spherical to ovoid, with collar and flagellum. Cells located in base of lorica composed of longitudinal and transverse costae. Base of lorica with numerous closely spaced transverse costae, expanded anterior part of lorica composed of approximately 12 longitudinal costae traversed at regular or irregular intervals by 4-6 transverse costae. Terminal transverse costa forming pore with small diameter (approximately 1 microns diameter). Cell 2.5-3 microns diameter, base of lorica 1.6-3.5 microns long, 3 microns diameter, anterior part of lorica 5-6.3 microns long, 5-6.3 microns diameter.
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Savillea parva (Ellis, 1930) Loeblich III, 1967. Cells are 2.5-4 microns (spherical), lorica 10-10.5 microns in length. The cell body is situated at the bottom of the lorica, the pseudopodial collar extends about two-thirds of the way up the lorica, and the flagellum extends to the top of the lorica. Unlike Savillea micropora, a flagellum is always present and active.
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Stephanoeca (steff-ann-owe-eek-a) is a collar flagellate in which the body is located within a lorica, which is made up of siliceous spicules. In this case the spicules cannot be seen individually. One cell (to the left) is active and has a flagellum projecting from the anterior of the cell and the base of the flagellum is surrounded by a collar of fine pseudopodia. The cell to the right seems to have encysted. Phase contrast micrograph.
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Stephanoeca (steff-ann-o-eek-a) diplocostata Ellis, 1929. Collar flagellate with lorica divided into two chambers by a waist at about two fifths of the distance from the base of lorica. Cells have a lorica with transverse and horizontal costae. The cells have a single apical flagellum. The flagellum is as long as the cell body. The cell body is about 10 microns long and fills the posterior chamber of the lorica. The lorica attaches to the substrate with a stalk or with the posterior end of the lorica. Rarely observed.