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Distatodinium virgatum
Distatodinium virgatum Stover, 1977
Holotype: Stover, 1977, pl.1, figs.20-21
Locus typicus: Corehole 5/5B, Blake Plateau, Western N Atlantic
Stratum typicum: Early Oligocene
Original description: Stover, 1977, p. 75-76
Cysts are chorate with an elongate ellipsoidal body having a smooth or faintly ornamented and thin autophragm, less than 0.5 Ám, that bears more than 50 processes. Processes are hollow, normally slender, generally with single stalks although an occasional process is simply branched near its base. Distally, the processes are trifurcate or rarely bifurcate with each arm simply branched; some processes, particularly those near or at the poles, may be distally wider and have more numerous branchings than the majority of processes. A single relatively wide process may occur at the antapical pole, and all processes are about the same length. Archeopyle is apical, type A, and the principal archeopyle suture is slightly angular; operculum not observed. Except for the archeopyle, indications of paratabulation are not readily apparent and the paracingulum and parasulcus are not expressed.
Overall length 110 to 124 Ám; exclusive of processes 70 to 83 Ám; processes 19 to 22 Ám longand 3 to 4 Ám wide, not including a wider antapical process present on some specimens.
Affinities: Stover, 1977, p. 76
Distatodinium virgatum differs from D. ellipticum (Cookson & Eisenack) Eaton, 1976 by having more numerous and more slender processes with considerably fewer and shorter tendril-like distal terminations. Although the holotype of D. ellipticum is clearly different from that of D. virgatum, the illustrated paratypes of D. ellipticum appear more similar to D. virgatum than to the holotype of D. ellipticum. The paratypes, however, differ from D. virgatum by having noticeably fewer processes and a punctoreticulate body; they probably represent an undescribed species.
Comment: Stover, 1977, p. 76
The smooth autophragm of Distatodinium virgatum is exceptionally thin and the processes appear to open directly into the autocoel; if two wall layers are present, they are not distinguishable with light microscopy.
Holotype: Stover, 1977, pl.1, figs.20-21
Locus typicus: Corehole 5/5B, Blake Plateau, Western N Atlantic
Stratum typicum: Early Oligocene
Original description: Stover, 1977, p. 75-76
Cysts are chorate with an elongate ellipsoidal body having a smooth or faintly ornamented and thin autophragm, less than 0.5 Ám, that bears more than 50 processes. Processes are hollow, normally slender, generally with single stalks although an occasional process is simply branched near its base. Distally, the processes are trifurcate or rarely bifurcate with each arm simply branched; some processes, particularly those near or at the poles, may be distally wider and have more numerous branchings than the majority of processes. A single relatively wide process may occur at the antapical pole, and all processes are about the same length. Archeopyle is apical, type A, and the principal archeopyle suture is slightly angular; operculum not observed. Except for the archeopyle, indications of paratabulation are not readily apparent and the paracingulum and parasulcus are not expressed.
Overall length 110 to 124 Ám; exclusive of processes 70 to 83 Ám; processes 19 to 22 Ám longand 3 to 4 Ám wide, not including a wider antapical process present on some specimens.
Affinities: Stover, 1977, p. 76
Distatodinium virgatum differs from D. ellipticum (Cookson & Eisenack) Eaton, 1976 by having more numerous and more slender processes with considerably fewer and shorter tendril-like distal terminations. Although the holotype of D. ellipticum is clearly different from that of D. virgatum, the illustrated paratypes of D. ellipticum appear more similar to D. virgatum than to the holotype of D. ellipticum. The paratypes, however, differ from D. virgatum by having noticeably fewer processes and a punctoreticulate body; they probably represent an undescribed species.
Comment: Stover, 1977, p. 76
The smooth autophragm of Distatodinium virgatum is exceptionally thin and the processes appear to open directly into the autocoel; if two wall layers are present, they are not distinguishable with light microscopy.