Ascostomocystis maxima, Singh, 1971

Holotype: C. Singh, 1971, pl.79, fig.3
Locus typicus: Peace River Area, Canada
Stratum typicum: Late Albian

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Original description: [Singh, 1971, p. 425-426]:

Description:
Test dorsoventrally flattened, elliptical in outline, and with an apical archaeopyle at one end; body wall double layered;
inner wall 1 to 2 microns thick and forming a thick rim around the apical archaeopyle;
outer wall membraneous, adhering to the inner wall dorsally and ventrally;
cingulum represented by two distinct, parallel transverse ridges on the outer membraneous wall and occasionally by a faint ridge on the inner wall; longitudinal ridges on the membraneous outer wall marking the outlines of plates;
plate arrangement not clear;
body smooth, light to dark brown in color.

Dimensions:
Range: length of test 135(143)155 µm, breadth of test 96(107)118 µm, width of archaeopyle 30(33)36 µm.

Affinities:
Ascostomocystis maxima is distinct from Ascostomocystis hydria, which is smaller and lacks the longitudinal ridges on the outer wall.