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Batiacasphaera asperata
Batiacasphaera asperata, Backhouse, 1987
Holotype: Backhouse, 1987, figs.10A-B
Locus typicus: Perth Basin, Australia
Stratum typicum: Valanginian-Hauterivian
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Original description: [Backhouse, 1987, p. 215]:
Description:
Small subspherical to ovoidal cyst, lacking apical and antapical protuberances and without preferred orientation. Autophragm about 1 µm thick; surface variably granular with individual grana less than 1 µm high, and normally less than 0.5 µm in diameter. Surface granulation may be reduced or worn.
Sulcal area may be indicated by a straight shallow groove passing from the sulcal notch onto the hypocyst.
Archeopyle apical, type [tA]; operculum normally missing. Shapes of the primary archeopyle suture and short accessory sutures indicating 6 precingular paraplates.
Other evidence of paratabulation absent.
Dimensions:
Length of holotype with operculum missing 48 µm, width 51 µm. Range of length with operculum missing (22 specimens) 43(49)60 µm, width 41(49)61 µm. Total length of one specimen 59 µm.
Affinities:
Small granular cysts of this type are widespread in the Early Cretaceous and can only be distinguished by careful assessment of the limited diagnostic criteria, namely overall shape, attachment or detachment of the operculum and precise type of surface feature. The most similar cyst is the undescribed form, Bafiacasphaera sp. Davey, 1979, (pl. 1, fig. 14). Specimens assigned by Burger (1980) to B. scrobiculata (Deflandre & Cookson) Burger 1980, appear to differ from B. asperata in details of surface sculpture which is slightly coarser in the paracingular zone (Burger, 1980). In addition, the width of the archeopyle in Burger"s specimens is considerably less than the maximum diameter of the cyst, whereas the archeopyle in B. asperata is wider in proportion to the width of the cyst.
Holotype: Backhouse, 1987, figs.10A-B
Locus typicus: Perth Basin, Australia
Stratum typicum: Valanginian-Hauterivian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Backhouse, 1987, p. 215]:
Description:
Small subspherical to ovoidal cyst, lacking apical and antapical protuberances and without preferred orientation. Autophragm about 1 µm thick; surface variably granular with individual grana less than 1 µm high, and normally less than 0.5 µm in diameter. Surface granulation may be reduced or worn.
Sulcal area may be indicated by a straight shallow groove passing from the sulcal notch onto the hypocyst.
Archeopyle apical, type [tA]; operculum normally missing. Shapes of the primary archeopyle suture and short accessory sutures indicating 6 precingular paraplates.
Other evidence of paratabulation absent.
Dimensions:
Length of holotype with operculum missing 48 µm, width 51 µm. Range of length with operculum missing (22 specimens) 43(49)60 µm, width 41(49)61 µm. Total length of one specimen 59 µm.
Affinities:
Small granular cysts of this type are widespread in the Early Cretaceous and can only be distinguished by careful assessment of the limited diagnostic criteria, namely overall shape, attachment or detachment of the operculum and precise type of surface feature. The most similar cyst is the undescribed form, Bafiacasphaera sp. Davey, 1979, (pl. 1, fig. 14). Specimens assigned by Burger (1980) to B. scrobiculata (Deflandre & Cookson) Burger 1980, appear to differ from B. asperata in details of surface sculpture which is slightly coarser in the paracingular zone (Burger, 1980). In addition, the width of the archeopyle in Burger"s specimens is considerably less than the maximum diameter of the cyst, whereas the archeopyle in B. asperata is wider in proportion to the width of the cyst.