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Areoligera tauloma
Areoligera tauloma, Eaton, 1976
Holotype: Eaton, 1976, pl.4, figs.1-2; Bujak et al., 1980, pl.9, figs.1-2
Locus typicus: Bracklesham Beds, Whitecliff Bay, Isle of Wight, England.
Stratum typicum: Middle-Late Eocene
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Original description: [Eaton, 1976, p. 247]:
Diagnosis:
Cyst body dorsoventrally flattened with a smooth or finely granular surface. The circular or subcircular outline may be modified by the development of one or two antapical protuberances. Ventral and dorsal surfaces bear sail-like membranes with deeply incised distal margins bearing numerous spines whose distal terminations are generally T-shaped, although a few may be blunt or acuminate. Ventral membrane restricted to the peripheral zone, aligned parallel to, and situated close to, the margin of the cyst body. Dorsal membranes organized into process complexes which may be arcuate, soleate or annular on the pre- and postcingular zones, linear on the cingular zone, and annular on the antapical zone.
Archaeopyle apical, tetratabular.
Dimensions:
Holotype: cyst body (without operculum) 59 x 68 µm; height of membrane (including spines) up to 32 µm.
Observed range: cyst body (without operculum) 44 x 50 µm to 62 x 76 µm; height of membrane (including spines) up to 32 µm. (n = 31).
Affinities: (p. 248):
The textural appearance of the membranes is similar to that of A. sentosa n. sp. The T-shaped distal terminations of the spines projecting from the membranes are formed by slightly recurved distal bifurcations, one part being sometimes longer than the other; blunt or acuminate terminations when present are always in a small minority. The variation in the type of process complex developed on the dorsal surface in A. tauloma is similar to that shown by A. sentosa. When linear complexes are developed on the cingular zone they are restricted to the lateral margins. No forms have been recorded with process complexes developed on the ventral surface. A. tauloma is distinguished from A. sentosa by having T-shaped terminations on the spinate distal extensions of the membranes. Cyclonephelium ordinatum Williams & Downie I966C has T-shaped distal terminations on its processes, but differs from A. tauloma in the distribution, extent and type of process complex development and the overall appearance of its processes.
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Heilmann-Clausen in Heilmann-Clausen and Costa, 1989, p. 463:
Remarks:
The terminations of the processes are generally simple, or only vaguely T-shaped.
Holotype: Eaton, 1976, pl.4, figs.1-2; Bujak et al., 1980, pl.9, figs.1-2
Locus typicus: Bracklesham Beds, Whitecliff Bay, Isle of Wight, England.
Stratum typicum: Middle-Late Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eaton, 1976, p. 247]:
Diagnosis:
Cyst body dorsoventrally flattened with a smooth or finely granular surface. The circular or subcircular outline may be modified by the development of one or two antapical protuberances. Ventral and dorsal surfaces bear sail-like membranes with deeply incised distal margins bearing numerous spines whose distal terminations are generally T-shaped, although a few may be blunt or acuminate. Ventral membrane restricted to the peripheral zone, aligned parallel to, and situated close to, the margin of the cyst body. Dorsal membranes organized into process complexes which may be arcuate, soleate or annular on the pre- and postcingular zones, linear on the cingular zone, and annular on the antapical zone.
Archaeopyle apical, tetratabular.
Dimensions:
Holotype: cyst body (without operculum) 59 x 68 µm; height of membrane (including spines) up to 32 µm.
Observed range: cyst body (without operculum) 44 x 50 µm to 62 x 76 µm; height of membrane (including spines) up to 32 µm. (n = 31).
Affinities: (p. 248):
The textural appearance of the membranes is similar to that of A. sentosa n. sp. The T-shaped distal terminations of the spines projecting from the membranes are formed by slightly recurved distal bifurcations, one part being sometimes longer than the other; blunt or acuminate terminations when present are always in a small minority. The variation in the type of process complex developed on the dorsal surface in A. tauloma is similar to that shown by A. sentosa. When linear complexes are developed on the cingular zone they are restricted to the lateral margins. No forms have been recorded with process complexes developed on the ventral surface. A. tauloma is distinguished from A. sentosa by having T-shaped terminations on the spinate distal extensions of the membranes. Cyclonephelium ordinatum Williams & Downie I966C has T-shaped distal terminations on its processes, but differs from A. tauloma in the distribution, extent and type of process complex development and the overall appearance of its processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Heilmann-Clausen in Heilmann-Clausen and Costa, 1989, p. 463:
Remarks:
The terminations of the processes are generally simple, or only vaguely T-shaped.