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Ascodinium verrucosum
Ascodinium verrucosum, Cookson and Hughes, 1964
Now Ovoidinium. Originally Ascodinium, subsequently (and now) Ovoidinium. Lentin and Williams (1989, p.270) retained this species in Ovoidinium.
Holotype: Cooksonand Hughes, 1964, pl.5, fig.4
Locus typicus: Barrington, Cambridgeshire, England
Stratum typicum: Cenomanian
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Original description: [Cookson and Hughes 1964, p. 41]:
Diagnosis:
Shell slightly longer than broad with strongly convex sides, a circular girdle and a short longitudinal furrow in the hypotheca. Shell-membrane completely adherent to the thicker wall of the capsule except at the extreme apex where it narrows towards a small, pointed, cap-like projection and antapically where it forms a prominent projection with a slanting asymmetrical base. The surface of the shell-membrane is ornamented with more or less densely arranged hollow verrucae; the wall of the capsule is unornamented, the two membranes together measure about 2-3 µm. Opening is effected by the complete detachment of the apical portion of the shell and capsule.
Dimensions:
Range: 55-80 µm long; 40-59 µm broad.
Remarks/Comment:
Considerable variation both in size of shell and density of ornament has been observed amongst the individuals included A. verrucosum, the larger shells having fewer and more widely spaced verrucae than the smaller ones.
Now Ovoidinium. Originally Ascodinium, subsequently (and now) Ovoidinium. Lentin and Williams (1989, p.270) retained this species in Ovoidinium.
Holotype: Cooksonand Hughes, 1964, pl.5, fig.4
Locus typicus: Barrington, Cambridgeshire, England
Stratum typicum: Cenomanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Hughes 1964, p. 41]:
Diagnosis:
Shell slightly longer than broad with strongly convex sides, a circular girdle and a short longitudinal furrow in the hypotheca. Shell-membrane completely adherent to the thicker wall of the capsule except at the extreme apex where it narrows towards a small, pointed, cap-like projection and antapically where it forms a prominent projection with a slanting asymmetrical base. The surface of the shell-membrane is ornamented with more or less densely arranged hollow verrucae; the wall of the capsule is unornamented, the two membranes together measure about 2-3 µm. Opening is effected by the complete detachment of the apical portion of the shell and capsule.
Dimensions:
Range: 55-80 µm long; 40-59 µm broad.
Remarks/Comment:
Considerable variation both in size of shell and density of ornament has been observed amongst the individuals included A. verrucosum, the larger shells having fewer and more widely spaced verrucae than the smaller ones.