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Scriniodinium crystallinum
Scriniodinium *crystallinum (Deflandre, 1939a, p.165, pl.5, figs.1–3) Klement, 1960, p.18. Emendation: Riding and Fensome, 2003, p.12–13.
Holotype: Deflandre, 1939a, pl.5, figs.1–2; Jan du Chêne et al., 1986a, pl.104, figs.1–4. Originally Gymnodinium (Appendix B), subsequently (and now) Scriniodinium. Taxonomic junior synonym: Scriniodinium playfordii, according to Jan du Chêne et al. (1986a, p.316) — however, Brenner (1988, p.79) retained Scriniodinium playfordii. This combination was not validly published in Klement (1957, p.409), since that author did not fully reference the basionym. Riding and Fensome (2003, p.18) considered this species to be the possible taxonomic senior synonym of Scriniodinium oxfordianum. Age: Oxfordian.
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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.
Scriniodinium crystallinum (Deflandre, 1939a) Klement, 1960. S.crystallinum is ovoidal, circumcavate with the only indications of tabulation being the cingulum, visible on the amb, and the archeopyle.. Size. Overall length 65-92 µm, width 58-85 µm.
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Original description: Deflandre 1938, p. 165: Gymnodinium crystallinum
An empty cyst enclosed in the membrane of the cell by which it is formed, both mostly strongly flattened. Both general appearance and relative dimensions are quite variable. Cell divided into two equal parts by a fairly straight transverse furrow. Epi- and hypotheca cannot be clearly distinguished because of the absence of a longitudinal furrow. Transverse furrow seems perfectly circular. One of the poles always seems to be largely rounded, while the other is slightly projected, forming a short mamelon-like protruberance. That pole may be considered the apex. Towards the transverse furrow the epi- and hypotheca widen a little like a bell. The transverse furrow may be more or less sharply pronounced, but remains straight. The cyst (inner body) is regularly ellipsoidal or sometimes slightly acuminate towards the apex to become ovoidal. Its wall is often quite thick. Normally the cyst has a large irregular opening, situated at the side of the epitheca. This opening may be interpret- ed as the excystment-opening. Dimension: generally: length 92(70)65 µm, breadth 85(65)58 µm.
Supplemental description: Klement 1960, p. 18.
Typical are the oval, dorsoventrally flattened appearance and bell- shaped epitheca and well-rounded hypotheca. Outer wall rather thin, inner wall firm. Tabulation not visible, but a regular trapezoidal opening with weakly convex sides, probably the excystment-opening, is present in some specimens. It is always situated middorsally on the epitheca, the base bordering the transverse furrow, the upper rim running somewhat below the apex. In form and site it corresponds to the 3rd pre-equatorial plate in tabulated species, that constitutes the pylome. The relatively narrow transverse furrow only visible in outline, and becoming more vague on the dorsal and ventral sides. No longitudinal furrow was observed. There is a relatively large variation in length/breadth ratio and in the size ratio between inner and outer wall. But both inner and outer wall follow the same length/breadth tendencies. There are extremely long specimens as well as specimens where the breadth exceeds the length. Length/breadth ratios are generally around 1.08-1.15 but exceptional values are 0.9 and 1.39.
Affinities:
Klement 1960, p. 19: Scriniodinium crystallinum differs from S. parvimarginatum and from S. attadalense. S. parvimarginatum has a weakly outstanding outer membrane in outline, and S. attadalense has the outline of quadrangle balancing on one of its corners. S. luridum has a typical sharp-angled antapex with a pronounced ventral transverse thickening, and clearly pronounced tabulation. S. galeritum also has clear tabulation.
Courtinat, 1989, p.217: Like in Endoscrinium galeritum and E. luridum, the endophragm in this species is connected to the periphragm by small pillars or spines.
Holotype: Deflandre, 1939a, pl.5, figs.1–2; Jan du Chêne et al., 1986a, pl.104, figs.1–4. Originally Gymnodinium (Appendix B), subsequently (and now) Scriniodinium. Taxonomic junior synonym: Scriniodinium playfordii, according to Jan du Chêne et al. (1986a, p.316) — however, Brenner (1988, p.79) retained Scriniodinium playfordii. This combination was not validly published in Klement (1957, p.409), since that author did not fully reference the basionym. Riding and Fensome (2003, p.18) considered this species to be the possible taxonomic senior synonym of Scriniodinium oxfordianum. Age: Oxfordian.
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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.
Scriniodinium crystallinum (Deflandre, 1939a) Klement, 1960. S.crystallinum is ovoidal, circumcavate with the only indications of tabulation being the cingulum, visible on the amb, and the archeopyle.. Size. Overall length 65-92 µm, width 58-85 µm.
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Original description: Deflandre 1938, p. 165: Gymnodinium crystallinum
An empty cyst enclosed in the membrane of the cell by which it is formed, both mostly strongly flattened. Both general appearance and relative dimensions are quite variable. Cell divided into two equal parts by a fairly straight transverse furrow. Epi- and hypotheca cannot be clearly distinguished because of the absence of a longitudinal furrow. Transverse furrow seems perfectly circular. One of the poles always seems to be largely rounded, while the other is slightly projected, forming a short mamelon-like protruberance. That pole may be considered the apex. Towards the transverse furrow the epi- and hypotheca widen a little like a bell. The transverse furrow may be more or less sharply pronounced, but remains straight. The cyst (inner body) is regularly ellipsoidal or sometimes slightly acuminate towards the apex to become ovoidal. Its wall is often quite thick. Normally the cyst has a large irregular opening, situated at the side of the epitheca. This opening may be interpret- ed as the excystment-opening. Dimension: generally: length 92(70)65 µm, breadth 85(65)58 µm.
Supplemental description: Klement 1960, p. 18.
Typical are the oval, dorsoventrally flattened appearance and bell- shaped epitheca and well-rounded hypotheca. Outer wall rather thin, inner wall firm. Tabulation not visible, but a regular trapezoidal opening with weakly convex sides, probably the excystment-opening, is present in some specimens. It is always situated middorsally on the epitheca, the base bordering the transverse furrow, the upper rim running somewhat below the apex. In form and site it corresponds to the 3rd pre-equatorial plate in tabulated species, that constitutes the pylome. The relatively narrow transverse furrow only visible in outline, and becoming more vague on the dorsal and ventral sides. No longitudinal furrow was observed. There is a relatively large variation in length/breadth ratio and in the size ratio between inner and outer wall. But both inner and outer wall follow the same length/breadth tendencies. There are extremely long specimens as well as specimens where the breadth exceeds the length. Length/breadth ratios are generally around 1.08-1.15 but exceptional values are 0.9 and 1.39.
Affinities:
Klement 1960, p. 19: Scriniodinium crystallinum differs from S. parvimarginatum and from S. attadalense. S. parvimarginatum has a weakly outstanding outer membrane in outline, and S. attadalense has the outline of quadrangle balancing on one of its corners. S. luridum has a typical sharp-angled antapex with a pronounced ventral transverse thickening, and clearly pronounced tabulation. S. galeritum also has clear tabulation.
Courtinat, 1989, p.217: Like in Endoscrinium galeritum and E. luridum, the endophragm in this species is connected to the periphragm by small pillars or spines.