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Endoscrinium variabile
Endoscrinium? variabile (Pocock, 1972) Jansonius, 1986
Originally Chytroeisphaeridia, subsequently Chytroeisphaeridia?, thirdly Gonyaulacysta, fourthly (and now) Endoscrinium?.
At the time of the transfer, Jansonius, 1986, questionably included this species in Endoscrinium.
Holotype: Pocock, 1972, pl.23, fig.15; Jansonius, 1986, pl.3, figs.15-17, text-fig.8; Jan du Chêne et al., 1986, pl.39, figs.5-7
Locus typicus: Tidewater Eastend Crown, W Canada
Stratum typicum: Late Bajocian
Original description: Pocock, 1972, p.100: Chytroeisphaeridia variabilis
Vesicle ovoid; sometimes differentiated into two portions, an epitheca with a, more or less pointed, solid apex and a hypotheca with a somewhat blunted antapex (Figs. 1--2); wall about 0.5 Ám thick; transparent; ornamented with scattered, low, rounded granules spaced 1.0--3.0 Ám apart; vesicle plated; plating too faint to determine tabulation; epitheca rounded; apex frequently marked by a short, wide horn up to 6.5 Ám long with a basal diameter of about 10.0 Ám; horn solid; penetrated by an apical pore; simple precingular archeopyle developed which may be closed with a shield-shaped operculum; helicoidal equatorial girdle present; frequently well developed; hypotheca smoothly rounded (pl.2, fig.1) or asymmetrically blunted at the antapex (pl.2, fig.2); antapical horns not developed; punctate yellow-green bodies present, fused to the inside of the vesicle wall; folds characteristically developed parallel to the sides of the grain which may give the grain the appearance of enclosing a spherical cyst; colourless to pale yellow; size range 60.0(68.1)81.0x45.0(53.7)57.0 Ám.
Supplemental description: Jansonius, 1986, p.207
(Holotype) Cyst in ventral aspect, wall two-layered, ca 65x54 Ám. Outer layer thin (0.3-0.4 Ám), hyaline, ovoid in outline, apically extended into a short rounded dome, external surface ornamented with low round granules, 0.4-0.8 Ám in diameter, 0.5 Ám high, rather widely and randomly scattered but some in small clusters, somewhat more dense within, and sparser over, those regions representing plate boundaries; however, this distribution is not sufficiently distinct to allow reconstruction of a paratabulation. Cingulum (5 Ám wide) barely helicoidal, on outline marked by a slight depression, and delineated by low discontinuous ridges. A precingular 3" archeopyle is delineated by a narrow groove (25 Ám high, 22 Ám wide on cingulum). No other expression of paratabulation. Several crescentic folds are developed, mostly near the outline and apex, falsely suggesting a central body to extend to just below the apical horn.
Inner body thin (0.25-0.3 Ám), hyaline, smooth, more or less circular, but along its periphery deformed by a number of crescentic folds, lacking evidence of paratabulation; enclosing two small clusters of chromatophores. It touches the right lateral margin of the periphragm but appears to be essentially free within the outer layer, leaving large apical and antapical pericoels. In the holotype, narrow folds filled with air accentuate the outline of inner and outer bodies.
Affinities:
Pocock, 1972, p.100: Chytroisphaeridia variabilis
A very variable species although the size range is reasonably narrow. In appearance the grains vary from typical "peridinoid" form with faint, but distinctly visible, plating to rounded ovoid granulose cysts.The archeopyle is present on all specimensalthough when the operculum is preserved it is not always obvious. All grains carry punctate yellow-green bodies.
Originally Chytroeisphaeridia, subsequently Chytroeisphaeridia?, thirdly Gonyaulacysta, fourthly (and now) Endoscrinium?.
At the time of the transfer, Jansonius, 1986, questionably included this species in Endoscrinium.
Holotype: Pocock, 1972, pl.23, fig.15; Jansonius, 1986, pl.3, figs.15-17, text-fig.8; Jan du Chêne et al., 1986, pl.39, figs.5-7
Locus typicus: Tidewater Eastend Crown, W Canada
Stratum typicum: Late Bajocian
Original description: Pocock, 1972, p.100: Chytroeisphaeridia variabilis
Vesicle ovoid; sometimes differentiated into two portions, an epitheca with a, more or less pointed, solid apex and a hypotheca with a somewhat blunted antapex (Figs. 1--2); wall about 0.5 Ám thick; transparent; ornamented with scattered, low, rounded granules spaced 1.0--3.0 Ám apart; vesicle plated; plating too faint to determine tabulation; epitheca rounded; apex frequently marked by a short, wide horn up to 6.5 Ám long with a basal diameter of about 10.0 Ám; horn solid; penetrated by an apical pore; simple precingular archeopyle developed which may be closed with a shield-shaped operculum; helicoidal equatorial girdle present; frequently well developed; hypotheca smoothly rounded (pl.2, fig.1) or asymmetrically blunted at the antapex (pl.2, fig.2); antapical horns not developed; punctate yellow-green bodies present, fused to the inside of the vesicle wall; folds characteristically developed parallel to the sides of the grain which may give the grain the appearance of enclosing a spherical cyst; colourless to pale yellow; size range 60.0(68.1)81.0x45.0(53.7)57.0 Ám.
Supplemental description: Jansonius, 1986, p.207
(Holotype) Cyst in ventral aspect, wall two-layered, ca 65x54 Ám. Outer layer thin (0.3-0.4 Ám), hyaline, ovoid in outline, apically extended into a short rounded dome, external surface ornamented with low round granules, 0.4-0.8 Ám in diameter, 0.5 Ám high, rather widely and randomly scattered but some in small clusters, somewhat more dense within, and sparser over, those regions representing plate boundaries; however, this distribution is not sufficiently distinct to allow reconstruction of a paratabulation. Cingulum (5 Ám wide) barely helicoidal, on outline marked by a slight depression, and delineated by low discontinuous ridges. A precingular 3" archeopyle is delineated by a narrow groove (25 Ám high, 22 Ám wide on cingulum). No other expression of paratabulation. Several crescentic folds are developed, mostly near the outline and apex, falsely suggesting a central body to extend to just below the apical horn.
Inner body thin (0.25-0.3 Ám), hyaline, smooth, more or less circular, but along its periphery deformed by a number of crescentic folds, lacking evidence of paratabulation; enclosing two small clusters of chromatophores. It touches the right lateral margin of the periphragm but appears to be essentially free within the outer layer, leaving large apical and antapical pericoels. In the holotype, narrow folds filled with air accentuate the outline of inner and outer bodies.
Affinities:
Pocock, 1972, p.100: Chytroisphaeridia variabilis
A very variable species although the size range is reasonably narrow. In appearance the grains vary from typical "peridinoid" form with faint, but distinctly visible, plating to rounded ovoid granulose cysts.The archeopyle is present on all specimensalthough when the operculum is preserved it is not always obvious. All grains carry punctate yellow-green bodies.