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Dissiliodinium giganteum
Dissiliodinium giganteum Feist-Burkhardt, 1990, p.616-617, pl.5, figs.1,3; pl.6, figs.1,4,7; text-figs.6-7.
Holotype: Feist-Burkhardt, 1990, pl.5, fig.1.
Locus typicus: Hausen an der Fils, Southwest Germany
Age: Aalenian-Early 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.
Dissiliodinium giganteum Feist-Burkhardt, 1990. Diagnosis from Feist-Burkhardt (1990), cyst proximate, subspherical. Autophragm thin, psilate, rarely scabrate. Archeopyle precingular, compound, type 2P-4P, formed by the loss of paraplates 3"-4", 2"-4", or 2"-5". Opercular pieces 3" and 4" free, 2" and/or 5" may be adherent. Apical paraplates remain attached to the hypocyst by a sied isthmus consisting of the paraplates 1", 6" and the parasulcal tongue. Paraplates of apical series differentiated. Paratabulation generally indicated only by archeopyle when precingular paraplates are separated or dislodged. Occasionally continuous or discontinuous grooves (appearing as dotted line) indicate the limits between the paraplates on the epicyst and the paracingulum. Epicystal paratabulation formula ?pr, 4', 0a, 6" + as. Precingular paraplates of unequal size and characteristic outline. 3" with rounded posterior angels and 1", 2", 4", 5", 6" with one, dorsally directed “stalk”-like elongate edge in adcingular position. 2" is extremely elongate, 1" is reduced and of a strongly asymmetrical camerate form. Paracingulum usually not expressed, sometimes indicated by a discontinuous transversal groove. Parasulcus can be indicated by a faint depression. at about midlength. Dissiliodinium giganteum differs from other species of the genus in having a psilate, rather than ornamented cyst wall. In D.globulum the isthmus connecting the apical cap with the hypocyst is formed by the as and 6" only. Size range; 90-124 µm
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Original diagnosis: Feist-Burkhardt, 1990, p. 616
Cyst proximate, subspherical Autophragm thin, psilate, rarely scabrate Archeopyle precingular. compound. type 2P - 4P, formed by the loss of the paraplates 3''-4'', 2''-4'' or 2''-5''. Opercular pieces 3'' and 4" free, 2'' and/or 5'' may be adherent Apical paraplates remain attached to the hypocyst by a wide isthmus consisting of the paraplates 1'', 6'' and the parasulcal tongue. Paraplates of apical series differentiated. Paratabulation generally indicated only by archeopyle when precingular paraplates are separated or dislodged Occasionally, continuous (Pl 6. fig. 1) or discontinuous (Pl. 6. fig 4, 7) grooves (appearing as dotted line) indicate the limits between the paraplates on the epicyst and the paracingulum. Epicystal paratabulation formula: ?pr, 4', 0a, 6'' + as (Fig 6) Precingular paraplates of unequal size and characteristic outline: 3'' with rounded posterior angles and 1", 2'', 4'', 5'', 6'' with one. dorsally directed "stalk"-like elongate edge in adcingular position; 2'' is extremely elongate, 1'' is reduced and of a strongly asymmetrical camerate form Paracingulum usually not expressed, sometimes indicated by a discontinuous transversal groove (Pl 6, fig 7) Parasulcus can be indicated by a faint depression (Pl. 6, fig 1, 4) Size range: 90 (110) 124 Ám at about midlength (26 specimens measured).
Affinities:
Feist-Burkhardt, 1990, p. 617:
Dissiliodinium giganteum differs from all other species of Dissilodinium Drugg 1978 in having a psilate rather than ornamented cystwall. In D. globulum Drugg 1978 the isthmus connecting the apical cap with the hypocyst is formed by as and 6'' only. D. caddaense Stover and Helby 1987 has an antapical bulge.
The specimen illustrated by Fenton et al. 1980, as Gongylodinium hocneratum (pl. 16, fig. 2) closely resembles Dissiliodinlum giganteum. Only the archeopyle type, described as type 2P, makes it impossible to include the forms here attributed to D. giganteum, in this species.
Holotype: Feist-Burkhardt, 1990, pl.5, fig.1.
Locus typicus: Hausen an der Fils, Southwest Germany
Age: Aalenian-Early 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.
Dissiliodinium giganteum Feist-Burkhardt, 1990. Diagnosis from Feist-Burkhardt (1990), cyst proximate, subspherical. Autophragm thin, psilate, rarely scabrate. Archeopyle precingular, compound, type 2P-4P, formed by the loss of paraplates 3"-4", 2"-4", or 2"-5". Opercular pieces 3" and 4" free, 2" and/or 5" may be adherent. Apical paraplates remain attached to the hypocyst by a sied isthmus consisting of the paraplates 1", 6" and the parasulcal tongue. Paraplates of apical series differentiated. Paratabulation generally indicated only by archeopyle when precingular paraplates are separated or dislodged. Occasionally continuous or discontinuous grooves (appearing as dotted line) indicate the limits between the paraplates on the epicyst and the paracingulum. Epicystal paratabulation formula ?pr, 4', 0a, 6" + as. Precingular paraplates of unequal size and characteristic outline. 3" with rounded posterior angels and 1", 2", 4", 5", 6" with one, dorsally directed “stalk”-like elongate edge in adcingular position. 2" is extremely elongate, 1" is reduced and of a strongly asymmetrical camerate form. Paracingulum usually not expressed, sometimes indicated by a discontinuous transversal groove. Parasulcus can be indicated by a faint depression. at about midlength. Dissiliodinium giganteum differs from other species of the genus in having a psilate, rather than ornamented cyst wall. In D.globulum the isthmus connecting the apical cap with the hypocyst is formed by the as and 6" only. Size range; 90-124 µm
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Original diagnosis: Feist-Burkhardt, 1990, p. 616
Cyst proximate, subspherical Autophragm thin, psilate, rarely scabrate Archeopyle precingular. compound. type 2P - 4P, formed by the loss of the paraplates 3''-4'', 2''-4'' or 2''-5''. Opercular pieces 3'' and 4" free, 2'' and/or 5'' may be adherent Apical paraplates remain attached to the hypocyst by a wide isthmus consisting of the paraplates 1'', 6'' and the parasulcal tongue. Paraplates of apical series differentiated. Paratabulation generally indicated only by archeopyle when precingular paraplates are separated or dislodged Occasionally, continuous (Pl 6. fig. 1) or discontinuous (Pl. 6. fig 4, 7) grooves (appearing as dotted line) indicate the limits between the paraplates on the epicyst and the paracingulum. Epicystal paratabulation formula: ?pr, 4', 0a, 6'' + as (Fig 6) Precingular paraplates of unequal size and characteristic outline: 3'' with rounded posterior angles and 1", 2'', 4'', 5'', 6'' with one. dorsally directed "stalk"-like elongate edge in adcingular position; 2'' is extremely elongate, 1'' is reduced and of a strongly asymmetrical camerate form Paracingulum usually not expressed, sometimes indicated by a discontinuous transversal groove (Pl 6, fig 7) Parasulcus can be indicated by a faint depression (Pl. 6, fig 1, 4) Size range: 90 (110) 124 Ám at about midlength (26 specimens measured).
Affinities:
Feist-Burkhardt, 1990, p. 617:
Dissiliodinium giganteum differs from all other species of Dissilodinium Drugg 1978 in having a psilate rather than ornamented cystwall. In D. globulum Drugg 1978 the isthmus connecting the apical cap with the hypocyst is formed by as and 6'' only. D. caddaense Stover and Helby 1987 has an antapical bulge.
The specimen illustrated by Fenton et al. 1980, as Gongylodinium hocneratum (pl. 16, fig. 2) closely resembles Dissiliodinlum giganteum. Only the archeopyle type, described as type 2P, makes it impossible to include the forms here attributed to D. giganteum, in this species.