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Ovoidinium turritum
Ovoidinium? turrita (Brideaux, 1977) Below, 1981
Now Canningia?. Originally (and now) Canningia?, subsequently Ovoidinium?.
Below, 1981, questionably included this species in Ovoidinium.
Lentin and Williams, 1985, questionably retained this species in Canningia Cookson and Eisenack, 1960.
Sangiorgi et al. (2009, p.252) speculated that this species may belong to Arcticacysta.
Holotype: Brideaux, 1977, pl.4, figs.1-3
Locus typicus: Richardson Mountains, Mackenzie District, Canada
Stratum typicum: Barremian
Original description: Brideaux, 1977, p. 13: Canningia turrita
Shape: Pericyst apex not observed; antapex rounded or with left antapical prominence developed. Endocyst as above, the two layers closely appressed and without pericoel development; dorso-ventral compression.
Phragma: Periphragm thin, less than 1.0 µm thick; the surface scabrate, or with scattered grana or coni less than 1.0 µm high. Endophragm thin, less than 0.5 µm thick and smooth.
Paratabulation Paratabulation of 4?', ?!1-3)a, 7'', 0c, ?''', ?'''', ?p, denoted by the shape of the archeopyle and accessory parasutures in the precingular paraplate series; other evidence for paratabulation lacking. Endophragm showing no evidence of paratabulation.
Archeopyle/operculum: Archeopyle interpreted as being formed by the loss of at least three apical paraplates (probably 2'-4') and one or three intercalary paraplates (1a or 1a-3a). Operculum free, never observed; the two layers probably separating as a unit.
Pericingulum/perisulcus: Surface expression of pericingulum not observed on periphragm; some specimens possessing slight invaginations of the profile at mid-latitudes interpreted as representing the position of the pericingulum; no surface expression of perisulcus on periphragm.
Dimensions - Overall length, complete specimens not observed, 37-55 µm; overall width, 34-55 µm.
Now Canningia?. Originally (and now) Canningia?, subsequently Ovoidinium?.
Below, 1981, questionably included this species in Ovoidinium.
Lentin and Williams, 1985, questionably retained this species in Canningia Cookson and Eisenack, 1960.
Sangiorgi et al. (2009, p.252) speculated that this species may belong to Arcticacysta.
Holotype: Brideaux, 1977, pl.4, figs.1-3
Locus typicus: Richardson Mountains, Mackenzie District, Canada
Stratum typicum: Barremian
Original description: Brideaux, 1977, p. 13: Canningia turrita
Shape: Pericyst apex not observed; antapex rounded or with left antapical prominence developed. Endocyst as above, the two layers closely appressed and without pericoel development; dorso-ventral compression.
Phragma: Periphragm thin, less than 1.0 µm thick; the surface scabrate, or with scattered grana or coni less than 1.0 µm high. Endophragm thin, less than 0.5 µm thick and smooth.
Paratabulation Paratabulation of 4?', ?!1-3)a, 7'', 0c, ?''', ?'''', ?p, denoted by the shape of the archeopyle and accessory parasutures in the precingular paraplate series; other evidence for paratabulation lacking. Endophragm showing no evidence of paratabulation.
Archeopyle/operculum: Archeopyle interpreted as being formed by the loss of at least three apical paraplates (probably 2'-4') and one or three intercalary paraplates (1a or 1a-3a). Operculum free, never observed; the two layers probably separating as a unit.
Pericingulum/perisulcus: Surface expression of pericingulum not observed on periphragm; some specimens possessing slight invaginations of the profile at mid-latitudes interpreted as representing the position of the pericingulum; no surface expression of perisulcus on periphragm.
Dimensions - Overall length, complete specimens not observed, 37-55 µm; overall width, 34-55 µm.