Back
Impletosphaeridium cracens
Impletosphaeridium cracens Eaton, 1976
Holotype: Eaton, 1976, pl.21, fig.6; Bujak et al., 1980, pl.5, fig.4
Locus typicus: Bracklesham Beds, Whitecliff Bay, Isle of Wight, England.
Stratum typicum: Early-Middle Eocene
Original diagnosis: Eaton, 1976, p. 306
Cyst body spherical or subspherical, with a smooth surface. Processes numerous, consisting of erect membranes of variable breadth, strengthened by rod-like thickenings. Processes simple or branched, frequently proximally united by lateral extension of the membranes. Distally the processes have a digitate or aculeate margin.
Dimensions: Holotype: diameter of cyst body 29 µm; length of processes up to 12 µm. Observed range: diameter of cyst body 18-30 µm; length of processes up to 13 µm. (n = 10).
Affinities:
Eaton, 1976, p. 306: The membranous processes with their rod-like thickenings distinguish I. cracens n. sp. from all described species of Impletosphaeridium. Cordosphaeridium? minimum (Morgenroth) Benedek 1972 also has rod-like thickenings in its processes, but the latter are distinctly tubular, and not erect membranes as in I. cracens.
Holotype: Eaton, 1976, pl.21, fig.6; Bujak et al., 1980, pl.5, fig.4
Locus typicus: Bracklesham Beds, Whitecliff Bay, Isle of Wight, England.
Stratum typicum: Early-Middle Eocene
Original diagnosis: Eaton, 1976, p. 306
Cyst body spherical or subspherical, with a smooth surface. Processes numerous, consisting of erect membranes of variable breadth, strengthened by rod-like thickenings. Processes simple or branched, frequently proximally united by lateral extension of the membranes. Distally the processes have a digitate or aculeate margin.
Dimensions: Holotype: diameter of cyst body 29 µm; length of processes up to 12 µm. Observed range: diameter of cyst body 18-30 µm; length of processes up to 13 µm. (n = 10).
Affinities:
Eaton, 1976, p. 306: The membranous processes with their rod-like thickenings distinguish I. cracens n. sp. from all described species of Impletosphaeridium. Cordosphaeridium? minimum (Morgenroth) Benedek 1972 also has rod-like thickenings in its processes, but the latter are distinctly tubular, and not erect membranes as in I. cracens.