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Spinidinium echinoideum
Spinidinium echinoideum (Cookson and Eisenack, 1960a, p.2, pl.1, figs.5–6) Lentin and Williams, 1976, p.64. Emendation: Sverdlove and Habib, 1974, p.58, as Deflandrea echinoidea.
Holotype: Cookson and Eisenack, 1960a, pl.1, figs.5.
Originally Deflandrea, subsequently (and now) Spinidinium, thirdly Vozzhennikovia, fourthly Spinidinium? Questionable assignment: Quattrocchio and Sarjeant (2003, p.136); however, Sluijs et al. (2009, p.47) retained the species in Spinidinium without question.
Age: Santonian–Campanian.
Original description: Cookson and Eisenack, 1960, p.2: Deflandrea echinoidea
Shell rather flat, somewhat pentagonal with convex sides, divided unequally by a circular gitdle with high borders into a smaller hypotheca, with a clearly defined pointed horn on one side, and occasional indications of a smaller one on the other side, and a larger epitheca which narrows towards the various shaped apex, usually carrying a tuft of spines. The broad longitudinal furrow is restricted to the hypotheca. The shell membrane is thin and fairly densely covered with thin, stiff spines (up to 5 µm long). The capsule is sphaerical, rather thinwalled, and fills the shell laterally. A pylome is sometimes developed. Dimensions: Holotype: 80 µm long; 57 µm broad; capsule ca. 43 µm. Range: 67-86 µm long; 50-57 µm broad.
Emended diagnosis: Sverdlove and Habib, 1974, p.58-59: Deflandrea echinoidea
Cavate cysts with peridinioid outline. One apical horn; two antapical horns, short more ol less reduced or absent. Epitract with convex sides, tuft of spines at apex. Circular-based spines, tapering to points distally, formed solely by periphragm, arranged suturallyor peritabularly, delineate cyst tabulation: 4", 3a, 7", ?6c, 5""", 1 - 2"""". Variable concentration of intratabular spines present. Average spine length, 1.0 micron; range, 0.5-3.0 microns. Periphragm between spines smooth to slightly granular. Capsule oval to subcircular, smooth, bears no spines: in variable amount of contact with periphragm in equatorial region. Archeopyle intercalary; Type l/l, plate 2a/2a. Periphragm may display accessory archeopyle sutures in precingular series causing irregular excystment apertures. Cingulum circular to slightly laevorotatory; divides cyst into smaller hypotract and larger epitract. Sulcus well developed on hypotract; extends onto epitract to base of plate 1". Cingulum and sulcus contain few intratabular spines; delimiting spines frequently proximally joined, forming thickened cyst wall. Dimensions: Fifty-three specimens were measured. The Maximum Length varied from 40 to 73 µm and the Maximum Width from 29 to 61 µm. The Apical Pericoel Length varied from 8 to 20 µm.
Affinities:
Sverdlove and Habib, 1974, p.59: Deflandrea echinoidea
This species is considered to be phylogenerically related to Defandrea vestita (Brideaux) Davey (1970) reported specimens lacking antapical horns and referred them to Deflandrea cf. D. echinoidea. The authors include such specimens within D. echinoidea because the length of the antapical horns is a variable characteristic of the species. Defandrea limpida Singh (1971) is considered a junior synonym of D. echinoidea because of the intraspecific variation of completeness of cyst tabulation and density of spine cover.
Holotype: Cookson and Eisenack, 1960a, pl.1, figs.5.
Originally Deflandrea, subsequently (and now) Spinidinium, thirdly Vozzhennikovia, fourthly Spinidinium? Questionable assignment: Quattrocchio and Sarjeant (2003, p.136); however, Sluijs et al. (2009, p.47) retained the species in Spinidinium without question.
Age: Santonian–Campanian.
Original description: Cookson and Eisenack, 1960, p.2: Deflandrea echinoidea
Shell rather flat, somewhat pentagonal with convex sides, divided unequally by a circular gitdle with high borders into a smaller hypotheca, with a clearly defined pointed horn on one side, and occasional indications of a smaller one on the other side, and a larger epitheca which narrows towards the various shaped apex, usually carrying a tuft of spines. The broad longitudinal furrow is restricted to the hypotheca. The shell membrane is thin and fairly densely covered with thin, stiff spines (up to 5 µm long). The capsule is sphaerical, rather thinwalled, and fills the shell laterally. A pylome is sometimes developed. Dimensions: Holotype: 80 µm long; 57 µm broad; capsule ca. 43 µm. Range: 67-86 µm long; 50-57 µm broad.
Emended diagnosis: Sverdlove and Habib, 1974, p.58-59: Deflandrea echinoidea
Cavate cysts with peridinioid outline. One apical horn; two antapical horns, short more ol less reduced or absent. Epitract with convex sides, tuft of spines at apex. Circular-based spines, tapering to points distally, formed solely by periphragm, arranged suturallyor peritabularly, delineate cyst tabulation: 4", 3a, 7", ?6c, 5""", 1 - 2"""". Variable concentration of intratabular spines present. Average spine length, 1.0 micron; range, 0.5-3.0 microns. Periphragm between spines smooth to slightly granular. Capsule oval to subcircular, smooth, bears no spines: in variable amount of contact with periphragm in equatorial region. Archeopyle intercalary; Type l/l, plate 2a/2a. Periphragm may display accessory archeopyle sutures in precingular series causing irregular excystment apertures. Cingulum circular to slightly laevorotatory; divides cyst into smaller hypotract and larger epitract. Sulcus well developed on hypotract; extends onto epitract to base of plate 1". Cingulum and sulcus contain few intratabular spines; delimiting spines frequently proximally joined, forming thickened cyst wall. Dimensions: Fifty-three specimens were measured. The Maximum Length varied from 40 to 73 µm and the Maximum Width from 29 to 61 µm. The Apical Pericoel Length varied from 8 to 20 µm.
Affinities:
Sverdlove and Habib, 1974, p.59: Deflandrea echinoidea
This species is considered to be phylogenerically related to Defandrea vestita (Brideaux) Davey (1970) reported specimens lacking antapical horns and referred them to Deflandrea cf. D. echinoidea. The authors include such specimens within D. echinoidea because the length of the antapical horns is a variable characteristic of the species. Defandrea limpida Singh (1971) is considered a junior synonym of D. echinoidea because of the intraspecific variation of completeness of cyst tabulation and density of spine cover.