Back
Hystrichosphaeridium asterium
Hystrichosphaeridium asterium Eaton, 1976
Now Melitasphaeridium. Originally Hystrichosphaeridium, subsequently (and now) Melitasphaeridium.
Holotype: Eaton, 1976, pl.11, figs.7-8
Locus typicus: Whitecliff Bay, Isle of Wight, England.
Stratum typicum: Late Eocene
Original diagnosis: Eaton, 1976, p. 273
Cyst body has a subcircular or rounded polygonal outline and a smooth surface. Processes about 20, tubular and usually slender and fairly constant in breadth. Each process is surmounted by a wide distal platform with usually 10 to 15 marginal aculei. Archaeopyle apical.
Dimensions: Holotype: cyst body (without operculum) 27x32 Ám; length of processes up to 13 Ám. Observed range: cyst body (without operculum) 22x22 to 30x34 Ám; length of processes up to 20 Ám. (n = 4).
Affinities:
Eaton, 1976, p. 273: None of the observed specimens is complete. The number of processes (about 20) indicates that there is one process per plate, reflecting the tabulation of the genus. The processes are occasionally expanded proximally-in one specimen (Pl. 11, fig. 9) one process shows considerable proximal expansion. The distal platforms which surmount each process are typically recurved, sometimes flat or slightly concave. Some processes show a reduction of the distal platform; these are similar to those of H. pseudorecurvatum Morgenroth 1966. Apart from the occasional presence of such processes, the small size of H. asterium and the distinctive form of the distal portion of its processes distinguish this species from all other described species of Hystrichosphaeridium.
Now Melitasphaeridium. Originally Hystrichosphaeridium, subsequently (and now) Melitasphaeridium.
Holotype: Eaton, 1976, pl.11, figs.7-8
Locus typicus: Whitecliff Bay, Isle of Wight, England.
Stratum typicum: Late Eocene
Original diagnosis: Eaton, 1976, p. 273
Cyst body has a subcircular or rounded polygonal outline and a smooth surface. Processes about 20, tubular and usually slender and fairly constant in breadth. Each process is surmounted by a wide distal platform with usually 10 to 15 marginal aculei. Archaeopyle apical.
Dimensions: Holotype: cyst body (without operculum) 27x32 Ám; length of processes up to 13 Ám. Observed range: cyst body (without operculum) 22x22 to 30x34 Ám; length of processes up to 20 Ám. (n = 4).
Affinities:
Eaton, 1976, p. 273: None of the observed specimens is complete. The number of processes (about 20) indicates that there is one process per plate, reflecting the tabulation of the genus. The processes are occasionally expanded proximally-in one specimen (Pl. 11, fig. 9) one process shows considerable proximal expansion. The distal platforms which surmount each process are typically recurved, sometimes flat or slightly concave. Some processes show a reduction of the distal platform; these are similar to those of H. pseudorecurvatum Morgenroth 1966. Apart from the occasional presence of such processes, the small size of H. asterium and the distinctive form of the distal portion of its processes distinguish this species from all other described species of Hystrichosphaeridium.