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Leptodinium volgense
From Fensome et al., 2019:
Leptodinium volgense Lentin and Williams, 1981, p.175. Holotype: Fisher and Riley, 1980, pl.1, figs.8,12; Jan du Chêne et al., 1986a, pl.67, fig.20. Originally Gonyaulacysta cristata, subsequently Leptodinium cristatum (combination illegitimate), thirdly (and now) Leptodinium volgense, fourthly Millioudodinium cristatum, fifthly Cribroperidinium cristatum (combination not validly published). Substitute name for Leptodinium cristatum (Riley in Fisher and Riley, 1980, p.320, pl.1, figs.8,12) Lentin and Williams, 1981, p.175 (an illegitimate name). Jan du Chêne et al. (1986a, p.210) retained this species in Leptodinium. Age: Volgian.
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Locus typicus: Dorset, England
Stratum typicum: Volgian
Original diagnosis: Riley, 1980, p.320: Gonyaulacysta cristata
A species of Gonyaulacysta with broadly ovoidal cyst. Apex bearing a strong, slender, apical horn; antapex rounded. Plate boundaries indicated by high, delicate, irregularly perforate crests with smooth distal edges. Refleeted tabulation 4', 6", 6c, 6''', 1p, ? 1pv, 1''''. Posterior ventral plate faintly indicated; possibly subdivided into small plates. Cingulum narrow, helicoid dividing the cyst unequally; epitract smaller than hypotract. Sulcus short, broadening posteriorly. Cyst wall, thick, densely granular.
Dimensions - Holotype: overall length 68 μm, breadth 42 μm, length of apical horn 9 μm, height of sutural crests 5-6 μm. Range: overall length 65-78 μm, breadth 40-45 μm, length of anical horn 9-10 μm.
Affinities:
Riley, 1980, p.320: This new species is superficially similar to G. perforans (Cookson and Eisenack) Sarjeant, differing in being smaller, in detail of reflected tabulation and sutural ornamentation and by lack of perforations in the cyst wall.
Leptodinium volgense Lentin and Williams, 1981, p.175. Holotype: Fisher and Riley, 1980, pl.1, figs.8,12; Jan du Chêne et al., 1986a, pl.67, fig.20. Originally Gonyaulacysta cristata, subsequently Leptodinium cristatum (combination illegitimate), thirdly (and now) Leptodinium volgense, fourthly Millioudodinium cristatum, fifthly Cribroperidinium cristatum (combination not validly published). Substitute name for Leptodinium cristatum (Riley in Fisher and Riley, 1980, p.320, pl.1, figs.8,12) Lentin and Williams, 1981, p.175 (an illegitimate name). Jan du Chêne et al. (1986a, p.210) retained this species in Leptodinium. Age: Volgian.
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Locus typicus: Dorset, England
Stratum typicum: Volgian
Original diagnosis: Riley, 1980, p.320: Gonyaulacysta cristata
A species of Gonyaulacysta with broadly ovoidal cyst. Apex bearing a strong, slender, apical horn; antapex rounded. Plate boundaries indicated by high, delicate, irregularly perforate crests with smooth distal edges. Refleeted tabulation 4', 6", 6c, 6''', 1p, ? 1pv, 1''''. Posterior ventral plate faintly indicated; possibly subdivided into small plates. Cingulum narrow, helicoid dividing the cyst unequally; epitract smaller than hypotract. Sulcus short, broadening posteriorly. Cyst wall, thick, densely granular.
Dimensions - Holotype: overall length 68 μm, breadth 42 μm, length of apical horn 9 μm, height of sutural crests 5-6 μm. Range: overall length 65-78 μm, breadth 40-45 μm, length of anical horn 9-10 μm.
Affinities:
Riley, 1980, p.320: This new species is superficially similar to G. perforans (Cookson and Eisenack) Sarjeant, differing in being smaller, in detail of reflected tabulation and sutural ornamentation and by lack of perforations in the cyst wall.