Batiacasphaera aptiensis, (Burger, 1980), Kumar,1986

Originally Tenua Eisenack, 1958, subsequently Sentusidinium, thirdly (and now) Batiacasphaera.
Tax. sr. synonym of Sentusidinium microrobustum (Morgan, 1980) Lentin and Williams, 1985, according to Backhouse, 1988.

Holotype: Burger 1980a: Pl. 23, figs. 1
Locus typicus: Bungil Formation, Minmi Member, Surat Basin, Australia
Stratum typicum: Cretaceous, early Aptian
Distribution: A rare species in some assemblages of the lower part of the Odontochitina operculata Zone.
Age: Aptian

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Original description as Tenua aptiense: [Burger 1980a, p. 76]:

Description:
Cyst spherical to egg-shaped; archaeopyle medium to large, apical, with a circular outline, margin irregularly dentate; a parasulcal notch is recognised in some specimens. No other traces of paratabulation are visible.
Autophragm thin, transparent, finely and evenly granulate, with more than 150 small, thin, tubular to conical, hollow processes 1-4 µm long, with acuminate or bifid tips.

Dimensions:
Apical diameter of 6 dehisced specimens 33-36 µm, width 35-42 µm.

Remarks/Affinities:
Because of the thin wall, specimens are usually badly torn in the preparations, so there are not enough suitable specimens to determine a satisfactory size range. The species is smaller than Tenua rioulti Sarjeant, 1968, and lacks a paracingulum and parasulcus.
Batiacasphaera baculata Drugg, 1970, resembles T. aptiense sp. nov. but has fewer and shorter, tuberculate processes.