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Dingodinium swanense
Dingodinium swanense Stover and Helby, 1987a, p.104-105,107, figs.3A-H.
Holotype: Stover and Helby, 1987a, figs.3A-B; Fensome et al., 1996, figs.1-2 - p.2393.
Locus typicus: Bonaparte Basin, Australia
Age: Kimmeridgian.
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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.
Dingodinium swanense Stover and Helby, 1987a, has a short, truncate, distally open apical horn. Endocyst closer to the pericyst dorsally than ventrally. Endophragm smooth except in the polar regions where it is verrucate, granulate and spinate. Granules and verrucae generally less than 2 µm in height. Spines 4-8 µm in length and generally contacting periphragm. They commonly occur along the anterior edge of the dorsal precingular paraplates. Archeopyle apical, endoarcheopyle angular and sometimes with short accessory sutures; periarcheopyle commonly obscure because of folding and tearing.Dingodinium swanense differs from D. jurassicum and D. cerviculum in the ornamentation being confined to the polar areas on the endocyst. It also differs from D. cerviculum in having the paracingulum at about midlength instead of being much closer to the posterior end and in having a shorter apical horn. Its ellipsoidal shape is also distinctive. Size: 114-137 µm..
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Original description: Stover and Helby, 1987, p. 104-105
Cysts proximate and camocavate; pericyst broadly elliptical in outline with a short, truncated apical, distally open horn. Endocyst usually narrowly elliptical and closer to the pericyst dorsally than ventrally. Periphragm smooth and frequently folded longitudinally; endophragm less frequently folded, also smooth except in the polar areas, and each wall layer about 1 Ám or less in thickness. Verrucae consistent on poles of endocyst where granules, or spines, or both may also be present. Granules and verrucae generally less than 2 Ám in height (occasional verrucae may be slightly higher) ranging in diameter from about 1-3.5 Ám; on most specimens, granules and verrucae not in contact with periphragm anteriorly, but may be so posteriorly. Spines from 4-8 Ám in length, 1 Ám to slightly more than 1 Ám in width at midlength, expanded distally and proximally, and generally contacting periphragm. These processes are commonly aligned along the anterior edge of dorsal precingular paraplates. On rare specimens the endophragm may be evenly covered with verrucae. Archeopyle apical, type [tA]a, endo-archeopyle angular, and sometimes with short accessory sutures; peri-archeopyle margin on the pericyst commonly obscure because of folding and tearing. Paracingulum either not expressed or indicated by subparallel, transverse folds of the periphragm at about midlength on both dorsal and ventral surfaces. Ends of paracingulum offset by approximately the width of the paracingulum. On some specimens periphragm between the ends of the paracingulum with subcircular to irregularly shaped opening varying from about 5-20 Ám in maximum diameter. Indications of a parasulcus not observed. Specimens 114-137 Ám long and 74-99 Ám wide; endophragms 90-116 Ám long and 40-62 Ám wide.
Affinities:
Stover and Helby, 1992, p. 105, 107: Dingodinium swanense differs from D. jurassicum Cookson & Eisenack 1958 and D. cerviculum Cookson & Eisenack 1958 in having ornamentation on the endocysts confined to the polar areas, rather than having it distributed on all or nearly all of the endocyst. Dingodinium swanense differs further from D. cerviculum in having the paracingulum at approximately midlength, instead of being much closer to the posterior than to the anterior end and in having a shorter apical horn. The strongly ellipsoidal shape of D. swanense is also distinctive.
Holotype: Stover and Helby, 1987a, figs.3A-B; Fensome et al., 1996, figs.1-2 - p.2393.
Locus typicus: Bonaparte Basin, Australia
Age: Kimmeridgian.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dingodinium swanense Stover and Helby, 1987a, has a short, truncate, distally open apical horn. Endocyst closer to the pericyst dorsally than ventrally. Endophragm smooth except in the polar regions where it is verrucate, granulate and spinate. Granules and verrucae generally less than 2 µm in height. Spines 4-8 µm in length and generally contacting periphragm. They commonly occur along the anterior edge of the dorsal precingular paraplates. Archeopyle apical, endoarcheopyle angular and sometimes with short accessory sutures; periarcheopyle commonly obscure because of folding and tearing.Dingodinium swanense differs from D. jurassicum and D. cerviculum in the ornamentation being confined to the polar areas on the endocyst. It also differs from D. cerviculum in having the paracingulum at about midlength instead of being much closer to the posterior end and in having a shorter apical horn. Its ellipsoidal shape is also distinctive. Size: 114-137 µm..
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Original description: Stover and Helby, 1987, p. 104-105
Cysts proximate and camocavate; pericyst broadly elliptical in outline with a short, truncated apical, distally open horn. Endocyst usually narrowly elliptical and closer to the pericyst dorsally than ventrally. Periphragm smooth and frequently folded longitudinally; endophragm less frequently folded, also smooth except in the polar areas, and each wall layer about 1 Ám or less in thickness. Verrucae consistent on poles of endocyst where granules, or spines, or both may also be present. Granules and verrucae generally less than 2 Ám in height (occasional verrucae may be slightly higher) ranging in diameter from about 1-3.5 Ám; on most specimens, granules and verrucae not in contact with periphragm anteriorly, but may be so posteriorly. Spines from 4-8 Ám in length, 1 Ám to slightly more than 1 Ám in width at midlength, expanded distally and proximally, and generally contacting periphragm. These processes are commonly aligned along the anterior edge of dorsal precingular paraplates. On rare specimens the endophragm may be evenly covered with verrucae. Archeopyle apical, type [tA]a, endo-archeopyle angular, and sometimes with short accessory sutures; peri-archeopyle margin on the pericyst commonly obscure because of folding and tearing. Paracingulum either not expressed or indicated by subparallel, transverse folds of the periphragm at about midlength on both dorsal and ventral surfaces. Ends of paracingulum offset by approximately the width of the paracingulum. On some specimens periphragm between the ends of the paracingulum with subcircular to irregularly shaped opening varying from about 5-20 Ám in maximum diameter. Indications of a parasulcus not observed. Specimens 114-137 Ám long and 74-99 Ám wide; endophragms 90-116 Ám long and 40-62 Ám wide.
Affinities:
Stover and Helby, 1992, p. 105, 107: Dingodinium swanense differs from D. jurassicum Cookson & Eisenack 1958 and D. cerviculum Cookson & Eisenack 1958 in having ornamentation on the endocysts confined to the polar areas, rather than having it distributed on all or nearly all of the endocyst. Dingodinium swanense differs further from D. cerviculum in having the paracingulum at approximately midlength, instead of being much closer to the posterior than to the anterior end and in having a shorter apical horn. The strongly ellipsoidal shape of D. swanense is also distinctive.