Back
Actinotheca
Actinosphaera, Cookson and Eisenack, 1960, p. 9
Type species: Cookson and Eisenack, 1960, Actinosphaera aphroditae
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1960]:
Description:
Shell roughly circular in outline, consisting of a flat, somewhat hexagonal box-like body and a broad two-layered wing which is supported by a series of radially directed fibres.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 200:
Synopsis: Cysts subspherical with high paracingular septa; gonal processes may occur on hypocyst; combination epicystal archeopyle, Type tAtP.
Description:
Shape: Body subspherical; outline of cyst in apical-antapical view circular, or nearly so (specimens commonly seen in this orientation).
Wall relationships: Wall layering virtually indistinguishable, except where periphragm projects beyond endophragm to form paracingular septa.
Wall features: High thin septa confined to paracingular area. Isolated gonal processes may occur on hypocyst; cyst surface smooth to faintly ornamented.
Paratabulation: Indicated by paracingular features only or, additionally, by gonal processes; probably gonyaulacacean; formula for epicyst unknown, for rest of cyst: 6c, 6```, 1p, 1````.
Archeopyle: Combination epicystal archeopyle, Type tAtP; principal archeopyle suture close to base of apical paracingular septum; operculum free.
Paracingulum: Indicated by high, parallel, transverse septa; boundaries between paraplates indicated by radial, rodlike thickenings or folds.
Parasulcus: Not indicated, or only vaguely so, on hypocyst; equatorial position corresponds to area between most closely spaced radial features on paracingular septa.
Size: Intermediate to large.
Affinities:
Actinotheca differs from Callaiosphaeridium in having the paracingulum expressed by high thin septa rather than intratabular processes. In addition, gonal processes are always present on the epicyst and hypocyst of Callaiosphaeridium; they may be present or absent on Actinotheca.
Type species: Cookson and Eisenack, 1960, Actinosphaera aphroditae
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1960]:
Description:
Shell roughly circular in outline, consisting of a flat, somewhat hexagonal box-like body and a broad two-layered wing which is supported by a series of radially directed fibres.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 200:
Synopsis: Cysts subspherical with high paracingular septa; gonal processes may occur on hypocyst; combination epicystal archeopyle, Type tAtP.
Description:
Shape: Body subspherical; outline of cyst in apical-antapical view circular, or nearly so (specimens commonly seen in this orientation).
Wall relationships: Wall layering virtually indistinguishable, except where periphragm projects beyond endophragm to form paracingular septa.
Wall features: High thin septa confined to paracingular area. Isolated gonal processes may occur on hypocyst; cyst surface smooth to faintly ornamented.
Paratabulation: Indicated by paracingular features only or, additionally, by gonal processes; probably gonyaulacacean; formula for epicyst unknown, for rest of cyst: 6c, 6```, 1p, 1````.
Archeopyle: Combination epicystal archeopyle, Type tAtP; principal archeopyle suture close to base of apical paracingular septum; operculum free.
Paracingulum: Indicated by high, parallel, transverse septa; boundaries between paraplates indicated by radial, rodlike thickenings or folds.
Parasulcus: Not indicated, or only vaguely so, on hypocyst; equatorial position corresponds to area between most closely spaced radial features on paracingular septa.
Size: Intermediate to large.
Affinities:
Actinotheca differs from Callaiosphaeridium in having the paracingulum expressed by high thin septa rather than intratabular processes. In addition, gonal processes are always present on the epicyst and hypocyst of Callaiosphaeridium; they may be present or absent on Actinotheca.