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Valvaeodinium spinosum
Valvaeodinium spinosum (Fenton et al., 1980) Below, 1987
Originally Kylindrocysta, subsequently (and now) Valvaeodinium.
Holotype: Fenton et al., 1980, pl.14, fig.13
Paratypes: Fenton et al., 1980
Locus typicus: Burton Bradstock, Dorset, England
Stratum typicum: Late Bajocian
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Valvaeodinium spinosum (Fenton et al., 1980) Below, 1987b, s a proximate cyst that is cylindrical, elongate or subquadrate in outline. The fibrous periphragm has numerous spines, blunt, pointed or occasionally capitate and 0.5-2 µm long. Spine coverage medium to dense. Size: length 31-56 µm, width 22-33 µm.
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Original diagnosis: Fenton et al., 1980, p. 162: Kylindrocysta spinosa
Proximate cyst, cylindrical, elongate or subquadrate in outline. Cyst wall complex, consisting of thin endophragm and thicker fibrous periphragm, the latter bears a spinose ornament of medium to dense distribution. The apex consists of five apical paraplates, two ?dorsally inclined, subquadrate paraplates, and three smaller paraplates on the ?ventral surface. Archaeopyle formed by the loss of the two former paraplates or combination of all five paraplates. Remainder of cyst composed of five elongate to subquadrate paraplates and a single antapical paraplate. Paratabulation formula 5', ?5", ?5''', 1''''.
Original description: Fenton et al., 1980, p. 162-163: Kylindrocysta spinosa
Cyst normally elongate, cylindrical in shape, occasionally becoming more subquadrate in outline, due to the reduction in the length of the five elongate paraplates, which constitute the bulk of the cyst. The sides are straight to convex, never concave. The double-layered wall consists of a smooth, thin endophragm and a spongy, fibrous periphragm, the combined thickness varying between 1 and 2 µm. The periphragm appears fibrous with the individual fibres coalescing to form blunt or pointed. rarely capitate, spines. 0.5-2 µm high. The spines are medium to densely distributed over the entire cyst surface.
The apex consists of five paraplates. Two large subquadrate paraplates occur inclined towards the assumed dorsal surface and these are normally lost first in archaeopyle formation, but may remain attached to a diamond-shaped paraplate on the assumed ventral surface. Either side of this latter paraplate is one smaller trapezoidal to subquadrate paraplate.
Five long paraplates make up the bulk of the cyst, occasionally defined by accessory archaeopyle parasutures extending posteriorly from the apex or anteriorly from the antapex (when the antapical paraplate is displaced or lost).
Dimensions. Cyst width--22(28)33 µm, length--31(45)56 µm; holotype width--33 µm, length--54 µm (31 specimens measured).
Originally Kylindrocysta, subsequently (and now) Valvaeodinium.
Holotype: Fenton et al., 1980, pl.14, fig.13
Paratypes: Fenton et al., 1980
Locus typicus: Burton Bradstock, Dorset, England
Stratum typicum: Late Bajocian
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Valvaeodinium spinosum (Fenton et al., 1980) Below, 1987b, s a proximate cyst that is cylindrical, elongate or subquadrate in outline. The fibrous periphragm has numerous spines, blunt, pointed or occasionally capitate and 0.5-2 µm long. Spine coverage medium to dense. Size: length 31-56 µm, width 22-33 µm.
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Original diagnosis: Fenton et al., 1980, p. 162: Kylindrocysta spinosa
Proximate cyst, cylindrical, elongate or subquadrate in outline. Cyst wall complex, consisting of thin endophragm and thicker fibrous periphragm, the latter bears a spinose ornament of medium to dense distribution. The apex consists of five apical paraplates, two ?dorsally inclined, subquadrate paraplates, and three smaller paraplates on the ?ventral surface. Archaeopyle formed by the loss of the two former paraplates or combination of all five paraplates. Remainder of cyst composed of five elongate to subquadrate paraplates and a single antapical paraplate. Paratabulation formula 5', ?5", ?5''', 1''''.
Original description: Fenton et al., 1980, p. 162-163: Kylindrocysta spinosa
Cyst normally elongate, cylindrical in shape, occasionally becoming more subquadrate in outline, due to the reduction in the length of the five elongate paraplates, which constitute the bulk of the cyst. The sides are straight to convex, never concave. The double-layered wall consists of a smooth, thin endophragm and a spongy, fibrous periphragm, the combined thickness varying between 1 and 2 µm. The periphragm appears fibrous with the individual fibres coalescing to form blunt or pointed. rarely capitate, spines. 0.5-2 µm high. The spines are medium to densely distributed over the entire cyst surface.
The apex consists of five paraplates. Two large subquadrate paraplates occur inclined towards the assumed dorsal surface and these are normally lost first in archaeopyle formation, but may remain attached to a diamond-shaped paraplate on the assumed ventral surface. Either side of this latter paraplate is one smaller trapezoidal to subquadrate paraplate.
Five long paraplates make up the bulk of the cyst, occasionally defined by accessory archaeopyle parasutures extending posteriorly from the apex or anteriorly from the antapex (when the antapical paraplate is displaced or lost).
Dimensions. Cyst width--22(28)33 µm, length--31(45)56 µm; holotype width--33 µm, length--54 µm (31 specimens measured).