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Kallosphaeridium helbyi ssp. psilatum
Kallosphaeridium? helbyi ssp. psilatum (Burger, 1980) Lentin and Williams, 1989
Originally Canningia? minor var. psilata, subsequently Canningia? minor ssp. psilata, thirdly Chytroeisphaeridia minor ssp. psilata, fourthly (and now) Kallosphaeridium? helbyi ssp. psilatum.
Lentin and Williams, 1981, raised this taxon to the subspecies level.
Holotype: Burger, 1980, pl.25, fig.10
Age: Aptian-Albian
Original description (Burger, 1980):
Holotype: BMR Roma 9, depth 78.8 m (258 ft 6 in.); Wallumbilla Formation, Coreena Member; Cretaceous, early Albian (MFP 6238-2, 323/1195; CPC 16341. PI. 25, fig. 10).
Description: Cyst spherical to egg-shaped, without apical or antapical horns. Archaeopyle apical with a circular outline, margin notched, outlining the presence of 6 precingular paraplates. No other traces of paratabulation are visible. Cyst wall single-layered, psilate, 0.5-1.5 µm thick.
Dimensions: Apical diameter (26 dehisced specimens) 32-(50)-65 µm, width (34 specimens) 26-(46)-84 µm.
Distribution: A rare to uncommon species in marine assemblages from the Surat Basin. Norvick (1975) reported similar specimens from the Cenomanian of Bathurst Island as Chytroeisphaeridia sp. aff. C. chytroeides (Sarjeant) Downie, Evitt & Sarjeant, 1963, and ?Chytroeisphaeridia sp. A; however, the genus Chytroeisphaeridia incorporates specimens with a precingular archaeopyle (Davey, pers. comm.).
Comments: The specimens from the Surat Basin are consistently psilate, in which respect they vary from Canningia minor itself.
Originally Canningia? minor var. psilata, subsequently Canningia? minor ssp. psilata, thirdly Chytroeisphaeridia minor ssp. psilata, fourthly (and now) Kallosphaeridium? helbyi ssp. psilatum.
Lentin and Williams, 1981, raised this taxon to the subspecies level.
Holotype: Burger, 1980, pl.25, fig.10
Age: Aptian-Albian
Original description (Burger, 1980):
Holotype: BMR Roma 9, depth 78.8 m (258 ft 6 in.); Wallumbilla Formation, Coreena Member; Cretaceous, early Albian (MFP 6238-2, 323/1195; CPC 16341. PI. 25, fig. 10).
Description: Cyst spherical to egg-shaped, without apical or antapical horns. Archaeopyle apical with a circular outline, margin notched, outlining the presence of 6 precingular paraplates. No other traces of paratabulation are visible. Cyst wall single-layered, psilate, 0.5-1.5 µm thick.
Dimensions: Apical diameter (26 dehisced specimens) 32-(50)-65 µm, width (34 specimens) 26-(46)-84 µm.
Distribution: A rare to uncommon species in marine assemblages from the Surat Basin. Norvick (1975) reported similar specimens from the Cenomanian of Bathurst Island as Chytroeisphaeridia sp. aff. C. chytroeides (Sarjeant) Downie, Evitt & Sarjeant, 1963, and ?Chytroeisphaeridia sp. A; however, the genus Chytroeisphaeridia incorporates specimens with a precingular archaeopyle (Davey, pers. comm.).
Comments: The specimens from the Surat Basin are consistently psilate, in which respect they vary from Canningia minor itself.