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Melitasphaeridium pseudorecurvatum
Melitasphaeridium pseudorecurvatum (Morgenroth, 1966) Bujak et al., 1980
Originally Hystrichosphaeridium, subsequently Operculodinium, thirdly (and now) Melitasphaeridium.
Taxonomic junior synonym: Hystrichosphaeridium sheppeyense, according to Stover and Evitt (1978, p.179).
Holotype: Morgenroth, 1966, pl. 8, fig. 5
Paratype(s): Morgenroth, 1966, pl. 8, fig. 6
Locus typicus: Isle of Fehmarn, Katharinenhof, N Germany
Stratum typicum: Early Eocene
Translation Morgenroth, 1966: LPP
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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.
Melitasphaeridium pseudorecurvatum (Morgenroth, 1966a) Bujak et al., 1980. From Morgenroth (1966a). The surface of the spherical to weakly ellipsoidal capsule is smooth. The thin wall is covered with about 15-35 processes whose length is almost always more or less equal to the capsule radius. The strongly cylindrical, slender processes (diameter 1-2 µm) possess a tiny distal opening which is surrounded by 6-8 stellate hooklets. The number of processes shows considerable variation. Many of the specimens possess a horseshoe shaped or trapezoidal archeopyle. Size: central body diameter 25-31 µm, process length 11-17 µm, archeopyle diameter 20 x 11 µm.
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Original description: Morgenroth, 1966, p. 30-31: Hystrichosphaeridium pseudorecurvatum
Diagnosis: The surface of the spherical-sometimes also weakly ellipsoidal-shell is structureles. The distinctly delicate shell wall is set with about 15-35 processes, the length of which is always about the shell radius. The strictly cylindrical processes (diameter 1-2 Ám) posses a tiny distal opening, which is surrounded by 6-8 little hooks, standing out in a stellate fashion.The number of processes varies considerably. - Many specimens have a horse-shoe shaped pylome, which, however, may sometimes also be delimited trapezoidally.
Dimensions: Shell diameter 30 Ám (25/31 Ám), process length 14 Ám (11/16 Ám), pylome 20x11 Ám (100 measurements). 150 specimens studied.
Affinities:
Bujak et al., 1980, p. 30
Hystrichosphaeridium sheppeyense is herein considered to be a junior synonym of Melitasphaeridium pseudorecurvatum. M. pseudorecurvatum, M. asterium, and M. choanophorum probably represent a stratigraphic sequence of morphotypes, with the oldest having distally aculeate processes and the youngest having entire distal process platforms. This may be paralleled by a reduction in the number of cingular and sulcal processes.
Originally Hystrichosphaeridium, subsequently Operculodinium, thirdly (and now) Melitasphaeridium.
Taxonomic junior synonym: Hystrichosphaeridium sheppeyense, according to Stover and Evitt (1978, p.179).
Holotype: Morgenroth, 1966, pl. 8, fig. 5
Paratype(s): Morgenroth, 1966, pl. 8, fig. 6
Locus typicus: Isle of Fehmarn, Katharinenhof, N Germany
Stratum typicum: Early Eocene
Translation Morgenroth, 1966: LPP
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Melitasphaeridium pseudorecurvatum (Morgenroth, 1966a) Bujak et al., 1980. From Morgenroth (1966a). The surface of the spherical to weakly ellipsoidal capsule is smooth. The thin wall is covered with about 15-35 processes whose length is almost always more or less equal to the capsule radius. The strongly cylindrical, slender processes (diameter 1-2 µm) possess a tiny distal opening which is surrounded by 6-8 stellate hooklets. The number of processes shows considerable variation. Many of the specimens possess a horseshoe shaped or trapezoidal archeopyle. Size: central body diameter 25-31 µm, process length 11-17 µm, archeopyle diameter 20 x 11 µm.
--------------------------------------------------
Original description: Morgenroth, 1966, p. 30-31: Hystrichosphaeridium pseudorecurvatum
Diagnosis: The surface of the spherical-sometimes also weakly ellipsoidal-shell is structureles. The distinctly delicate shell wall is set with about 15-35 processes, the length of which is always about the shell radius. The strictly cylindrical processes (diameter 1-2 Ám) posses a tiny distal opening, which is surrounded by 6-8 little hooks, standing out in a stellate fashion.The number of processes varies considerably. - Many specimens have a horse-shoe shaped pylome, which, however, may sometimes also be delimited trapezoidally.
Dimensions: Shell diameter 30 Ám (25/31 Ám), process length 14 Ám (11/16 Ám), pylome 20x11 Ám (100 measurements). 150 specimens studied.
Affinities:
Bujak et al., 1980, p. 30
Hystrichosphaeridium sheppeyense is herein considered to be a junior synonym of Melitasphaeridium pseudorecurvatum. M. pseudorecurvatum, M. asterium, and M. choanophorum probably represent a stratigraphic sequence of morphotypes, with the oldest having distally aculeate processes and the youngest having entire distal process platforms. This may be paralleled by a reduction in the number of cingular and sulcal processes.