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Ovoidinium fragile
Ovoidinium? fragile Norvick in Norvick and Burger, 1976
Originally (and now) Ovoidinium?, subsequently Ascodinium?.
Lentin and Williams, 1985, questionably transferred this species to Ascodinium Cookson and Eisenack, 1960. Lentin and Williams, 1989, questionably retained it in Ovoidinium.
Norvick in Norvick and Burger, 1976, questionably included the species in Ovoidinium.
Holotypus: Norvick, 1976, pl.13, fig.1
Locus typicus: Bathurst Island no. 1 well, Australia
Stratum typicum: Cenomanian
Original diagnosis: Norvick, 1976, p.88
Cyst bicavate, pericoel interrupted at a broad cingulum. Cyst shape peridinioid, with one apical and either one or two dissimilar antapical horns. Inner capsule subspherical. Endophragm and periphragm extremely thin and readily folded, smooth or very faintly granulate. Archaeopyle an irregular apical opening in both membranes, lower at one side of the cyst than at the other.
Description: Norvick, 1976, p.88
Cavate cyst, composed of two extremely thin, smooth or very faintly granulate membranes. The endophragm and periphragm are in close contact in the cingular region but diverge to form apical and antapical pericoels. A tapering apical horn and one or two, dissimilar, tapering antapical horns are present. One of the antapical horns is often much reduced; where it is absent, the remaining horn is offset from the median line. The cingulum is broad (about 5 Ám wide) and is sometimes interrupted by a shallow sulcus. Most specimens examined are undehisced, but a small number are truncated by a somewhat irregular opening, which removes the apex of both membranes and is lower at one side of the cyst than at the other. It is questionably interpreted as a combination apical-intercalary archaeopyle.
Dimensions: The overall length of 30 measured specimens is in the range 41(60)75 Ám.
Originally (and now) Ovoidinium?, subsequently Ascodinium?.
Lentin and Williams, 1985, questionably transferred this species to Ascodinium Cookson and Eisenack, 1960. Lentin and Williams, 1989, questionably retained it in Ovoidinium.
Norvick in Norvick and Burger, 1976, questionably included the species in Ovoidinium.
Holotypus: Norvick, 1976, pl.13, fig.1
Locus typicus: Bathurst Island no. 1 well, Australia
Stratum typicum: Cenomanian
Original diagnosis: Norvick, 1976, p.88
Cyst bicavate, pericoel interrupted at a broad cingulum. Cyst shape peridinioid, with one apical and either one or two dissimilar antapical horns. Inner capsule subspherical. Endophragm and periphragm extremely thin and readily folded, smooth or very faintly granulate. Archaeopyle an irregular apical opening in both membranes, lower at one side of the cyst than at the other.
Description: Norvick, 1976, p.88
Cavate cyst, composed of two extremely thin, smooth or very faintly granulate membranes. The endophragm and periphragm are in close contact in the cingular region but diverge to form apical and antapical pericoels. A tapering apical horn and one or two, dissimilar, tapering antapical horns are present. One of the antapical horns is often much reduced; where it is absent, the remaining horn is offset from the median line. The cingulum is broad (about 5 Ám wide) and is sometimes interrupted by a shallow sulcus. Most specimens examined are undehisced, but a small number are truncated by a somewhat irregular opening, which removes the apex of both membranes and is lower at one side of the cyst than at the other. It is questionably interpreted as a combination apical-intercalary archaeopyle.
Dimensions: The overall length of 30 measured specimens is in the range 41(60)75 Ám.