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Litosphaeridium arundum
Litosphaeridium arundum (Eisenack and Cookson, 1960, p.8, pl.3, figs.7–9) Davey, 1979b, p.557. Emendation: Lucas-Clark, 1984, p.188, as Litosphaeridium arundum
Originally Hystrichosphaeridium, subsequently Hystrichosphaeridium?, thirdly (and now) Litosphaeridium.
Taxonomic senior synonym: Micrhystridium (as Dapsilidinium?, now Litosphaeridium) fucosum, according to Below (1982c, p.29) — however, Lentin and Williams (1985, p.227) retained Hystrichosphaeridium (as Litosphaeridium) arundum.
Holotype: Eisenack and Cookson, 1960, pl.3, fig.7; Helby et al., 1987, figs.29J–K.
Locus typicus: Oodnadatta Bore, S Australia
Stratum typicum: Albian
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Litosphaeridium arundum (Eisenack and Cookson, 1960) Davey, 1979b, emend. Lucas-Clark, 1984, has 35-45 discrete hollow processes, three to four on the operculum, archeopyle with adnate operculum. Periphragm granular to reticulate. Processes cylindrical to gently tapering, circular at base, open distally, truncated or slightly flared at the tips. Process tips thickened into a rim or finely scalloped. One to four processes per paraplate. Cingular processes cylindrical open, smaller and more slender than pre- and postcingular processes, usually two per paraplate. Size: diameter of shell 24-32 µm, overall diameter 38-57 µm.
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Original description: Eisenack and Cookson, 1960, p. 8: Hystrichosphaeridium arundum
Shell sphaerical, slightly granular, provided with approximately 30 short, funnel-shaped appendages with delicate recurved edges. The width of the appandages may be uniform or variable in one and the same example. A pylome has not been observed despite the relative frequency of this species.
Dimensions: Type: diameter of shell 28 µm, overall diameter 42 µm. Range: dimater of shell 24-32 µm, overall diamter 38-57 µm.
Emended Description: Lucas-Clark, 1984, p. 188
Skolochorate apiculocavate cysts with subspherical to ovoid central body and a total of 35 to about 45 discrete, hollow processes (three to four on operculum). Archeopyle apical, adnate ventrally. Periphragm ornament, which is granular to finely reticulate, extends onto the processes, and becomes finer towards process tips. Endophragm ornament, which is different from that on periphragm, visibly only beneath processes. Processes cylindrical to gently tapering, circular at the base, truncated or slightly flared at the tips. Process tips thickened into a rim or finely scalloped. Process shafts circular to oval in cross-section. Processes representing paraplates B, C (or Ci and Cu), 1i, 1u, 2-6, ai, au, b-e, fi, Iu, II-VI, X, Y, and Z; one to four per paraplate. Cingular processes cylindrical, open, smaller and more slender than pre- and postcingular processes, usually two per paraplate. Sulcal processes open; ai usually represented by two processes, Iu and Z by one each. Apical, pre- and postcingular processes open.
Affinities:
Eisenack and Cookson, 1960, p. 8: Hystrichosphaeridium arundum
Hystrichsphaeridium arundum is considerably smaller and has more numerous appandages than H. siphonophorum Cookson and Eisenack; it is also clearly distinct from H. salipingophorum Deflandre.
Davey 1979, p. 557: Litosphaeridium arundum comb.nov. closely resembles L.conispinum Davey and Verdier, 1973, in most respects including the number of processes, except that the paracingular and parasulcal processess of the former tubular. In both species the paracingular and parasulcal processes are narrower than the other processes. The operculum usually remains attached in L.arundum and on one specimen was observed to bear three processes as does the operculum of L.siphonisphorum (Cookson and Eisenack, 1958).
Originally Hystrichosphaeridium, subsequently Hystrichosphaeridium?, thirdly (and now) Litosphaeridium.
Taxonomic senior synonym: Micrhystridium (as Dapsilidinium?, now Litosphaeridium) fucosum, according to Below (1982c, p.29) — however, Lentin and Williams (1985, p.227) retained Hystrichosphaeridium (as Litosphaeridium) arundum.
Holotype: Eisenack and Cookson, 1960, pl.3, fig.7; Helby et al., 1987, figs.29J–K.
Locus typicus: Oodnadatta Bore, S Australia
Stratum typicum: Albian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Litosphaeridium arundum (Eisenack and Cookson, 1960) Davey, 1979b, emend. Lucas-Clark, 1984, has 35-45 discrete hollow processes, three to four on the operculum, archeopyle with adnate operculum. Periphragm granular to reticulate. Processes cylindrical to gently tapering, circular at base, open distally, truncated or slightly flared at the tips. Process tips thickened into a rim or finely scalloped. One to four processes per paraplate. Cingular processes cylindrical open, smaller and more slender than pre- and postcingular processes, usually two per paraplate. Size: diameter of shell 24-32 µm, overall diameter 38-57 µm.
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Original description: Eisenack and Cookson, 1960, p. 8: Hystrichosphaeridium arundum
Shell sphaerical, slightly granular, provided with approximately 30 short, funnel-shaped appendages with delicate recurved edges. The width of the appandages may be uniform or variable in one and the same example. A pylome has not been observed despite the relative frequency of this species.
Dimensions: Type: diameter of shell 28 µm, overall diameter 42 µm. Range: dimater of shell 24-32 µm, overall diamter 38-57 µm.
Emended Description: Lucas-Clark, 1984, p. 188
Skolochorate apiculocavate cysts with subspherical to ovoid central body and a total of 35 to about 45 discrete, hollow processes (three to four on operculum). Archeopyle apical, adnate ventrally. Periphragm ornament, which is granular to finely reticulate, extends onto the processes, and becomes finer towards process tips. Endophragm ornament, which is different from that on periphragm, visibly only beneath processes. Processes cylindrical to gently tapering, circular at the base, truncated or slightly flared at the tips. Process tips thickened into a rim or finely scalloped. Process shafts circular to oval in cross-section. Processes representing paraplates B, C (or Ci and Cu), 1i, 1u, 2-6, ai, au, b-e, fi, Iu, II-VI, X, Y, and Z; one to four per paraplate. Cingular processes cylindrical, open, smaller and more slender than pre- and postcingular processes, usually two per paraplate. Sulcal processes open; ai usually represented by two processes, Iu and Z by one each. Apical, pre- and postcingular processes open.
Affinities:
Eisenack and Cookson, 1960, p. 8: Hystrichosphaeridium arundum
Hystrichsphaeridium arundum is considerably smaller and has more numerous appandages than H. siphonophorum Cookson and Eisenack; it is also clearly distinct from H. salipingophorum Deflandre.
Davey 1979, p. 557: Litosphaeridium arundum comb.nov. closely resembles L.conispinum Davey and Verdier, 1973, in most respects including the number of processes, except that the paracingular and parasulcal processess of the former tubular. In both species the paracingular and parasulcal processes are narrower than the other processes. The operculum usually remains attached in L.arundum and on one specimen was observed to bear three processes as does the operculum of L.siphonisphorum (Cookson and Eisenack, 1958).