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Leberidocysta chlamydata subsp. chlamydata
Leberidocysta chlamydata subsp. chlamydata
Autonym.
Holotype: Cookson and Eisenack, 1962b, pl.7, fig.2; Fensome et al., 1993a, fig.2 - p.1049.
Locus typicus: Brickhouse Bore, Carnarvon, W Australia
Stratum typicum: Albian-Cenomanian
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Original description: Cookson and Eisenack, 1962, p. 496: Hexagonifera chlamydata
Shell broadly oval, rather thick-walled, surface finely to coarsely verrucose, completely enclosed in a thin, smooth, hyaline membrane that may extend for some distance laterally and posteriorly or may occasionally be entirely removed.
Dimensions: Holotype: Over-all length 75 Ám; width 76 Ám; shell 60x50 Ám.
Range: Over-all length ca. 68-75 Ám; width ca. 42-54 Ám; shell 56-68x42-54 Ám.
Emended description: Fechner, 1985, p.119
The cavate cyst shows an ellipsoidal relatively thick-walled endophragm with a smooth to granular appearance and a commonly complexly folded thin periphragm. The periphragm and endophragm are attdched only along the Zig-Zag line of the apical archeopyle type tA. In the absence of an archeopyle, endophragm and periphragm are merely loosely attached. While parasutural features of the endophragm are confined to the apical region, expressed simply by an apical horn, the periphragm with its random arrangement of folds provides more information about the paratabulation (Text-fig. 5)
-- Considering the tetragonal apical horn of the endophragm and the hexagonal horn of the periphragm, the existence of 4 - 6 apical paraplates becomes likely. -- The zig-zag line of the archeopyle margin suggests further the presence of 5 - 6 precingular parapIates . -- No signs of intercalary paraplates were found. --Since the antapex of the periphragm is frequently somewhat angular in shape, this area is possibly occupied by only one paraplate. -- Beyond that, the periphragm shows occasionally an arrangement of folds which conceivably mark parasulcus and paracingulum. -- All of the above results in the following preliminary paratabulation formula: 5 - 6", ?C, ?''', ?p, 1'''', ?r.
Affinities: Cookson and Eisenack, 1962, p. 496: Hexagonifera chlamydata
H. chlamydata is distinguishable from the Upper Cretaceous species H. vermiculata by the type of the sulpture and the greater prominence and constancy of the outer membrane.
Autonym.
Holotype: Cookson and Eisenack, 1962b, pl.7, fig.2; Fensome et al., 1993a, fig.2 - p.1049.
Locus typicus: Brickhouse Bore, Carnarvon, W Australia
Stratum typicum: Albian-Cenomanian
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Original description: Cookson and Eisenack, 1962, p. 496: Hexagonifera chlamydata
Shell broadly oval, rather thick-walled, surface finely to coarsely verrucose, completely enclosed in a thin, smooth, hyaline membrane that may extend for some distance laterally and posteriorly or may occasionally be entirely removed.
Dimensions: Holotype: Over-all length 75 Ám; width 76 Ám; shell 60x50 Ám.
Range: Over-all length ca. 68-75 Ám; width ca. 42-54 Ám; shell 56-68x42-54 Ám.
Emended description: Fechner, 1985, p.119
The cavate cyst shows an ellipsoidal relatively thick-walled endophragm with a smooth to granular appearance and a commonly complexly folded thin periphragm. The periphragm and endophragm are attdched only along the Zig-Zag line of the apical archeopyle type tA. In the absence of an archeopyle, endophragm and periphragm are merely loosely attached. While parasutural features of the endophragm are confined to the apical region, expressed simply by an apical horn, the periphragm with its random arrangement of folds provides more information about the paratabulation (Text-fig. 5)
-- Considering the tetragonal apical horn of the endophragm and the hexagonal horn of the periphragm, the existence of 4 - 6 apical paraplates becomes likely. -- The zig-zag line of the archeopyle margin suggests further the presence of 5 - 6 precingular parapIates . -- No signs of intercalary paraplates were found. --Since the antapex of the periphragm is frequently somewhat angular in shape, this area is possibly occupied by only one paraplate. -- Beyond that, the periphragm shows occasionally an arrangement of folds which conceivably mark parasulcus and paracingulum. -- All of the above results in the following preliminary paratabulation formula: 5 - 6", ?C, ?''', ?p, 1'''', ?r.
Affinities: Cookson and Eisenack, 1962, p. 496: Hexagonifera chlamydata
H. chlamydata is distinguishable from the Upper Cretaceous species H. vermiculata by the type of the sulpture and the greater prominence and constancy of the outer membrane.