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Hystrichosphaeridium costatum
Hystrichosphaeridium costatum Davey and Williams, 1966
NOW Compositosphaeridium Dodekova. Originally Hystrichosphaeridium, subsequently Cordosphaeridium, thirdly (and now) Compositosphaeridium Dodekova.
Taxonomic senior synonym: Hystrichosphaeridium (now Compositosphaeridium?) polonicum, according to Beju (1971, p.292) - however, Masure in Fauconnier and Masure (2004, p.137) retained Compositosphaeridium costatum.
Holotype: Davey and Williams, 1966, pl.10, fig.4; Stancliffe and Sarjeant, 1990, pl.3, fig.1
Locus typicus: Yorkshire, England
Stratum typicum: Oxfordian
Original diagnosis: Davey and Williams, 1966, p. 63
Subspherical central body possessing a moderate number of fibrous tubiform processes having sub-quadrate distal openings. Distal margin denticulate with small number of recurved prolongations. Thickened ribs extending from some of the angles of the distal margins along length of processes and onto central body surface where they connect with similar ribs extending from neighbouring processes, forming mesh-like structure. Apical archaeopyle usually present.
Dimensions: holotype: diameter of central body 47 by 47 Ám, length of processes
19-28 Ám.
Original description: Davey and Williams, 1966, p. 63
The surface (periphragm) of the central body is granular or slightly reticulate. The tubiform processes have broad bases, and splay out distally in an angular fashion, their width not exceeding 9Á medially. At the angles of the margin are commonly situated small prolongations or spines, occasionally up to 8 long but usually considerably smaller. The processes vary considerably in width, from 1 to 9 Ám when measured medially. Only one or two finer processes are present on a specimen and these are probably sulcal processes. An occasional deeply furcate process has been observed in the central region of the cyst, these undoubtedly being cingulum processes. The ribs (thickenings of the periphragm) are very characteristic and form upon the surface of the central body a subpolygonal mesh-like arrangement, somewhat simulating the tabulation seen in the genus Hystrichosphaera, but certainly not analogous to it. An apical archaeopyle is usually present, and the reflected tabulation appears to be that typical for this genus.
NOW Compositosphaeridium Dodekova. Originally Hystrichosphaeridium, subsequently Cordosphaeridium, thirdly (and now) Compositosphaeridium Dodekova.
Taxonomic senior synonym: Hystrichosphaeridium (now Compositosphaeridium?) polonicum, according to Beju (1971, p.292) - however, Masure in Fauconnier and Masure (2004, p.137) retained Compositosphaeridium costatum.
Holotype: Davey and Williams, 1966, pl.10, fig.4; Stancliffe and Sarjeant, 1990, pl.3, fig.1
Locus typicus: Yorkshire, England
Stratum typicum: Oxfordian
Original diagnosis: Davey and Williams, 1966, p. 63
Subspherical central body possessing a moderate number of fibrous tubiform processes having sub-quadrate distal openings. Distal margin denticulate with small number of recurved prolongations. Thickened ribs extending from some of the angles of the distal margins along length of processes and onto central body surface where they connect with similar ribs extending from neighbouring processes, forming mesh-like structure. Apical archaeopyle usually present.
Dimensions: holotype: diameter of central body 47 by 47 Ám, length of processes
19-28 Ám.
Original description: Davey and Williams, 1966, p. 63
The surface (periphragm) of the central body is granular or slightly reticulate. The tubiform processes have broad bases, and splay out distally in an angular fashion, their width not exceeding 9Á medially. At the angles of the margin are commonly situated small prolongations or spines, occasionally up to 8 long but usually considerably smaller. The processes vary considerably in width, from 1 to 9 Ám when measured medially. Only one or two finer processes are present on a specimen and these are probably sulcal processes. An occasional deeply furcate process has been observed in the central region of the cyst, these undoubtedly being cingulum processes. The ribs (thickenings of the periphragm) are very characteristic and form upon the surface of the central body a subpolygonal mesh-like arrangement, somewhat simulating the tabulation seen in the genus Hystrichosphaera, but certainly not analogous to it. An apical archaeopyle is usually present, and the reflected tabulation appears to be that typical for this genus.