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Dingodinium jurassicum
From Fensome et al., 2019:
Dingodinium jurassicum Cookson and Eisenack, 1958, p.39, pl.1, figs.10–11. Emendation: Pestchevitskaya, 2018, p.100.
Holotype: Cookson and Eisenack, 1958, pl.1, fig.10; Helby et al., 1987, fig.18F. Age: Late Jurassic.
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Original description: Cookson and Eisenack, 1958, p. 39
Shell usually longer than broad with a shallow girdle. The capsulae, which tends to be flattened on the side in contact with outer membrane, is covered with numerous small irregularly dispoded spines.
Dimensions: Type - 58 x 66 µm, capsule 62 x 47 µm. Overall range - 76-100 x 66-85 µm, capsule 54-71 x 47-66 µm.
Poulsen 1996, p. 82
Dingodinium jurassicum Cookson & Eisenack 1958, Pl. 16, Fig. 13
Remarks. See Table 3.
Recorded occurrences.
Denmark: Trichodinium scarburghense Zone, Subzone b - Gochteodinia villosa Zone, Rotosphaeropsis thula Subzone.
Poland: Bimammatum - Tenuicostata zones.
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Emendation by Pestchevitskaya, 2018 (p. 688):
Diagnosis emended. Proximate, camocavate dinocysts with combination (?) archeopyle. Pericyst and endocyst ellipsoidal without apical horn.
Periphragm transparent, smooth; endophragm thicker, spinous. Pericoel wide. Tabulation of cladopixiaceous type, expressed by sutural features, stressed by folds and low psilate crests on pericyst, formula 4'?, Xa?, 7''?, Xc, 6''', 1p, 1''''. Cingulum and sulcus expressed by sutural features on endocyst, by folds and low psilate crests on pericyst.
Description (Fig. 4b). The dinocysts are proximate, camocavate. The pericyst and endocyst are broadly ellipsoidal, sometimes almost spherical. The apical horn is absent. Sometimes the endocyst can be slightly ovoid, but extended in height. The pericoel is wide on the ventral side and narrow on the dorsal side; it can be absent, in the zone of intercalary plates. The periphragm is transparent, smooth, easily folded. The endophragm is denser, ornamented by relatively large and acute spines, which can be higher, narrow-conical and/or lower, wide-conical. The tabulation is of cladopixiaceous type, expressed on the endocyst by sutural features, and on the pericyst it is often expressed by low smooth crests and emphasized by folds. The crests are more expressed in the cingulum, and sometimes the sulcus and antapex. In the apical area the crests are very low, the tabulation is usually delineated here by sutural features and is poorly discernible. The tabulation formula is 4'?, Xa?, 7''?, Xc, 6''', 1p, 1''''. The cingulum and sulcus are expressed on the pericysts by crests and are usually emphasized by folds, and on the endocyst it is expressed by sutural features. The morphology of the archeopyle is unclear.
Comparison. It is distinguished from other species of the genus by the absence of the apical horn. Additionally, it differs from D. albertii in the ellipsoid shape of the peri- and endocyst, and from D. cooksoniae and D. tuberosum (Gitmez, 1970) it differs in the wide pericoel.
Remarks. The emended diagnosis of the species contains new data on tabulation, and the tabulation of the post-cingular region. The presence of crests on the pericysts emphasizing tabulation is discovered. It is established that the species has an elongated pericyst and endocyst, and there are no transitional forms to the morphotype with a round, isometric cyst, and a weakly pronounced apical horn. The present author’s observations and published materials (Stover and Helby, 1987a) show that the archeopyle is formed due to loss of climactal plates. However it was not possible to study its detailed morphology based on the material from the Gorodishche Section because of the absence of specimens with a partly preserved operculum, which could have confirmed the presence of intercalary plates.
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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 jurassicum Cookson and Eisenack, 1958. Following the diagnosis of Cookson and Eisenack (1958), pericyst usually longer than broad with a shallow cingulum. The endocyst, which tends to be flattened on the side in contact with the outer membrane, is covered with numerous, small, irregularly disposed spines. Size: type 85 x 66 µm, capsule 62 x 47 µm, overall range 76-100 x 66-85 µm, capsule 54-71 x 47-66 µm.
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Dingodinium jurassicum Cookson and Eisenack, 1958, p.39, pl.1, figs.10–11. Emendation: Pestchevitskaya, 2018, p.100.
Holotype: Cookson and Eisenack, 1958, pl.1, fig.10; Helby et al., 1987, fig.18F. Age: Late Jurassic.
---------------------------------------------------------------------------------------------------
Original description: Cookson and Eisenack, 1958, p. 39
Shell usually longer than broad with a shallow girdle. The capsulae, which tends to be flattened on the side in contact with outer membrane, is covered with numerous small irregularly dispoded spines.
Dimensions: Type - 58 x 66 µm, capsule 62 x 47 µm. Overall range - 76-100 x 66-85 µm, capsule 54-71 x 47-66 µm.
Poulsen 1996, p. 82
Dingodinium jurassicum Cookson & Eisenack 1958, Pl. 16, Fig. 13
Remarks. See Table 3.
Recorded occurrences.
Denmark: Trichodinium scarburghense Zone, Subzone b - Gochteodinia villosa Zone, Rotosphaeropsis thula Subzone.
Poland: Bimammatum - Tenuicostata zones.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emendation by Pestchevitskaya, 2018 (p. 688):
Diagnosis emended. Proximate, camocavate dinocysts with combination (?) archeopyle. Pericyst and endocyst ellipsoidal without apical horn.
Periphragm transparent, smooth; endophragm thicker, spinous. Pericoel wide. Tabulation of cladopixiaceous type, expressed by sutural features, stressed by folds and low psilate crests on pericyst, formula 4'?, Xa?, 7''?, Xc, 6''', 1p, 1''''. Cingulum and sulcus expressed by sutural features on endocyst, by folds and low psilate crests on pericyst.
Description (Fig. 4b). The dinocysts are proximate, camocavate. The pericyst and endocyst are broadly ellipsoidal, sometimes almost spherical. The apical horn is absent. Sometimes the endocyst can be slightly ovoid, but extended in height. The pericoel is wide on the ventral side and narrow on the dorsal side; it can be absent, in the zone of intercalary plates. The periphragm is transparent, smooth, easily folded. The endophragm is denser, ornamented by relatively large and acute spines, which can be higher, narrow-conical and/or lower, wide-conical. The tabulation is of cladopixiaceous type, expressed on the endocyst by sutural features, and on the pericyst it is often expressed by low smooth crests and emphasized by folds. The crests are more expressed in the cingulum, and sometimes the sulcus and antapex. In the apical area the crests are very low, the tabulation is usually delineated here by sutural features and is poorly discernible. The tabulation formula is 4'?, Xa?, 7''?, Xc, 6''', 1p, 1''''. The cingulum and sulcus are expressed on the pericysts by crests and are usually emphasized by folds, and on the endocyst it is expressed by sutural features. The morphology of the archeopyle is unclear.
Comparison. It is distinguished from other species of the genus by the absence of the apical horn. Additionally, it differs from D. albertii in the ellipsoid shape of the peri- and endocyst, and from D. cooksoniae and D. tuberosum (Gitmez, 1970) it differs in the wide pericoel.
Remarks. The emended diagnosis of the species contains new data on tabulation, and the tabulation of the post-cingular region. The presence of crests on the pericysts emphasizing tabulation is discovered. It is established that the species has an elongated pericyst and endocyst, and there are no transitional forms to the morphotype with a round, isometric cyst, and a weakly pronounced apical horn. The present author’s observations and published materials (Stover and Helby, 1987a) show that the archeopyle is formed due to loss of climactal plates. However it was not possible to study its detailed morphology based on the material from the Gorodishche Section because of the absence of specimens with a partly preserved operculum, which could have confirmed the presence of intercalary plates.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dingodinium jurassicum Cookson and Eisenack, 1958. Following the diagnosis of Cookson and Eisenack (1958), pericyst usually longer than broad with a shallow cingulum. The endocyst, which tends to be flattened on the side in contact with the outer membrane, is covered with numerous, small, irregularly disposed spines. Size: type 85 x 66 µm, capsule 62 x 47 µm, overall range 76-100 x 66-85 µm, capsule 54-71 x 47-66 µm.
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