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Meiourogonyaulax pertusa ssp. pertusa

Meiourogonyaulax pertusa ssp. pertusa

Autonym.
Originally (and now) Meiourogonyaulax pertusa subsp. pertusa, subsequently Lithodinia pertusa subsp. pertusa.
Holotype: Duxbury, 1977, pl.8, fig.5, text-fig.15; Fensome et al., 1991, figs.1-3-p.709; figs.1-3-p.711
Locus typicus: Speeton, England
Stratum typicum: Berriasian-Hauterivian

Original description: Duxbury 1977, p. 42: Lithodinia pertusa
Diagnosis: A fairly thick-walled proximate cyst. Test wall perforate with very low sutural crests outlining the tabulation 4", 6"", 7c, 7""", 1p, 1pv, 1"""". Archeopyle apical.
Observed dimensions: Holotype 76x81 Ám; Archeopyle formed 65-76x68-86 Ám; Specimens measured: 7.

Affinities:
Duxbury, 1977, p. 43
The form which bears the closest resemblance to Lithodinia pertusa is that described as Gonyaulacysta bulloidea in Cookson adn Eisenack, 1960 and later transferred to Meiourogonyaulax in Sarjeant, 1969. However, in their diagnosis of Gonyaulax bulloidea, Cookson and Eisenack refer to the "granular" nature of both plates and crets. The plates and crests of Lithodinia pertusa are distinctly perforate.
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