Back
Achomosphaera robusta
From Fensome et al., 2019:
Achomosphaera? robusta, Sah et al., 1970, p.145, pl.1, figs.6–7.
Holotype: Sah et al., 1970, pl.1, fig.6.
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]:
Achomosphaera robusta sp. nov.
PI. 1, Figs. 6-7
Holotype -- Pl. 1, Fig. 6. Size 70 x 64 μ.
Slide no. 3642.
No. of specimens studied- 9.
Diagnosis -- Cyst oval-subcircular, 61-76 x 58-75 μ; archeopyle precingular, simple; processes many, strongly built, dichotomising at the tips; cyst membrane thin, laevigate, sometimes intrastructured.
Description -- Cysts generally oval with broadly rounded lateral ends. Archeopyle ± squarely-rhomboidal, operculum found attached in some specimens. Processes up to 30 μ in length and 12 μ in breadth. Tips mostly bifurcating, sometimes trifurcating. Cyst membrane 1-1·5 μ thick, an intrastructure discernible in some specimens, which seems to be intrapunctate.
Comparison -- Achomosphaera sagena Dav. & Will. (1966) is comparable in shape and size range but differs in having a thicker cyst membrane and well developed sculptural elements. A. alcicornu (Eisen.) GerI. (1961) differs in having longer tubular processes. A. neptuni (Eisen.) Gocht (1959) has a central body with a reticulate or occasionally slightly fibrous surface.
Achomosphaera? robusta, Sah et al., 1970, p.145, pl.1, figs.6–7.
Holotype: Sah et al., 1970, pl.1, fig.6.
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]:
Achomosphaera robusta sp. nov.
PI. 1, Figs. 6-7
Holotype -- Pl. 1, Fig. 6. Size 70 x 64 μ.
Slide no. 3642.
No. of specimens studied- 9.
Diagnosis -- Cyst oval-subcircular, 61-76 x 58-75 μ; archeopyle precingular, simple; processes many, strongly built, dichotomising at the tips; cyst membrane thin, laevigate, sometimes intrastructured.
Description -- Cysts generally oval with broadly rounded lateral ends. Archeopyle ± squarely-rhomboidal, operculum found attached in some specimens. Processes up to 30 μ in length and 12 μ in breadth. Tips mostly bifurcating, sometimes trifurcating. Cyst membrane 1-1·5 μ thick, an intrastructure discernible in some specimens, which seems to be intrapunctate.
Comparison -- Achomosphaera sagena Dav. & Will. (1966) is comparable in shape and size range but differs in having a thicker cyst membrane and well developed sculptural elements. A. alcicornu (Eisen.) GerI. (1961) differs in having longer tubular processes. A. neptuni (Eisen.) Gocht (1959) has a central body with a reticulate or occasionally slightly fibrous surface.