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Millioudodinium cristatum
Millioudodinium cristatum (Riley in Fisher and Riley, 1980) Fisher and Riley, 1982
Now Leptodinium volgense. Originally Gonyaulacysta cristata, subsequently (and now) Leptodinium volgense, thirdly Millioudodinium cristatum. See also Cribroperidinium cristatum (combination not validly published) and Leptodinium cristatum (combination illegitimate).
Holotype: Fisher and Riley, 1980, pl.1, figs.8,12; Jan du Chêne et al., 1986, pl.67, fig.20
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 Ám, breadth 42 Ám, length of apical horn 9 Ám, height of sutural crests 5-6 Ám. Range: overall length 65-78 Ám, breadth 40-45 Ám, length of anical horn 9-10 Ám.
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.
Now Leptodinium volgense. Originally Gonyaulacysta cristata, subsequently (and now) Leptodinium volgense, thirdly Millioudodinium cristatum. See also Cribroperidinium cristatum (combination not validly published) and Leptodinium cristatum (combination illegitimate).
Holotype: Fisher and Riley, 1980, pl.1, figs.8,12; Jan du Chêne et al., 1986, pl.67, fig.20
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 Ám, breadth 42 Ám, length of apical horn 9 Ám, height of sutural crests 5-6 Ám. Range: overall length 65-78 Ám, breadth 40-45 Ám, length of anical horn 9-10 Ám.
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.