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Palaeocystodinium benjaminii
Palaeocystodinium benjaminii Drugg, 1967
Holotype: Drugg, 1967, pl.3, fig.1
Locus typicus: Escarpado Canyon, California
Stratum typicum: Maastrichtian-Danian
Original diagnosis: Drugg, 1967, p.31
Test spindle-shaped. Two horns, one at each end, tapered and either pointed or slightly blunted. These horns are covered with fine hairs or processes up to 3 microns long standing at right angles to the long axis of the horn. The ends of these hairs are capitate. The antapical horn is often forked part way along its length, the fork giving rise to a much reduced second horn. An ellipsoidal inner body is always present. The membranes of both the inner and outer bodies are delicate, transparent, and usually smooth, although the membrane of the inner body may sometimes be lightly granulate. This seems to be a variable feature. A rounded pentagonal archeopyle is visible. There is no evidence of any furrows.
Dimensions: Holotype 172µm, 55µm broad; cyst 81x55µm; range 130 - 300µm long, 28 - 67µm broad.
Affinities:
Drugg, 1967, p.31: This species is very close to P. golzowense. The main difference is the presence of the fine processes on the horns of the upper Moreno specimens, and the presence of the rudimentary second antapical horn. This latter feature suggests a possible relationship Palaeocystodinium and Deflandrea. Svalbardella australina is close to P. benjaminii but differs by exhibiting traces of a girdle structure and by lacking fine processes on the horns.
Holotype: Drugg, 1967, pl.3, fig.1
Locus typicus: Escarpado Canyon, California
Stratum typicum: Maastrichtian-Danian
Original diagnosis: Drugg, 1967, p.31
Test spindle-shaped. Two horns, one at each end, tapered and either pointed or slightly blunted. These horns are covered with fine hairs or processes up to 3 microns long standing at right angles to the long axis of the horn. The ends of these hairs are capitate. The antapical horn is often forked part way along its length, the fork giving rise to a much reduced second horn. An ellipsoidal inner body is always present. The membranes of both the inner and outer bodies are delicate, transparent, and usually smooth, although the membrane of the inner body may sometimes be lightly granulate. This seems to be a variable feature. A rounded pentagonal archeopyle is visible. There is no evidence of any furrows.
Dimensions: Holotype 172µm, 55µm broad; cyst 81x55µm; range 130 - 300µm long, 28 - 67µm broad.
Affinities:
Drugg, 1967, p.31: This species is very close to P. golzowense. The main difference is the presence of the fine processes on the horns of the upper Moreno specimens, and the presence of the rudimentary second antapical horn. This latter feature suggests a possible relationship Palaeocystodinium and Deflandrea. Svalbardella australina is close to P. benjaminii but differs by exhibiting traces of a girdle structure and by lacking fine processes on the horns.