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Achomosphaera convexa
From Fensome et al., 2019:
Achomosphaera? convexa, Sah et al., 1970, p.145–146, pl.1, figs.12–13.
Holotype: Sah et al., 1970, pl.1, fig.12.
Originally Achomosphaera, subsequently (and now) Achomosphaera?.
Questionable assignment: Stover and Evitt (1978, p.139).
Age: Late Cretaceous.
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Original description: [Sah et al., 1970, p.145–146]:
Achomosphaera convexa sp.nov.
PI.1, Figs.12-13
Holotype - PI. 1, Fig. 12. Size 77 X 66 µm.
Slide no. 3644.
No. of specimens studied – 9.
Diagnosis – Cysts oval with biconvex sides and pointed lateral ends; size range 60-77 X 46-66 µm; archeopyle precingular, simple; processes well developed, ± uniform; cyst membrane laevigate.
Description – Strong biconvex sides of the cysts provide the characteristic shape of this species. Lateral ends are acutely rounded. Archeopyle can be seen in some specimens. Processes up to 20 µm long, mostly with bifurcating tips, generally uniform, in some specimens processes at cingulr and antapical regions seem to be better developed. Cyst membrane 1-1⋅ 5 µm thick, laevigate, irregularly folded.
Comparison – Achomosphaera cambra somewhat resembles the present species in shape and size range but differs in possessing spinose processes which are joined together at the cingular region. A.ramulifera (DefIan.) Evitt (1963) is oval with broadly rounded lateral ends and has very long and well developed bifid processes. A. delicata has many baculate processes which are up to 10 µm long.
Achomosphaera? convexa, Sah et al., 1970, p.145–146, pl.1, figs.12–13.
Holotype: Sah et al., 1970, pl.1, fig.12.
Originally Achomosphaera, subsequently (and now) Achomosphaera?.
Questionable assignment: Stover and Evitt (1978, p.139).
Age: Late Cretaceous.
---------------------------------------------------------------------------------------------------
Original description: [Sah et al., 1970, p.145–146]:
Achomosphaera convexa sp.nov.
PI.1, Figs.12-13
Holotype - PI. 1, Fig. 12. Size 77 X 66 µm.
Slide no. 3644.
No. of specimens studied – 9.
Diagnosis – Cysts oval with biconvex sides and pointed lateral ends; size range 60-77 X 46-66 µm; archeopyle precingular, simple; processes well developed, ± uniform; cyst membrane laevigate.
Description – Strong biconvex sides of the cysts provide the characteristic shape of this species. Lateral ends are acutely rounded. Archeopyle can be seen in some specimens. Processes up to 20 µm long, mostly with bifurcating tips, generally uniform, in some specimens processes at cingulr and antapical regions seem to be better developed. Cyst membrane 1-1⋅ 5 µm thick, laevigate, irregularly folded.
Comparison – Achomosphaera cambra somewhat resembles the present species in shape and size range but differs in possessing spinose processes which are joined together at the cingular region. A.ramulifera (DefIan.) Evitt (1963) is oval with broadly rounded lateral ends and has very long and well developed bifid processes. A. delicata has many baculate processes which are up to 10 µm long.