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Dissiliodinium volkheimeri
From Fensome et al., 2019:
Dissiliodinium volkheimeri Quattrocchio and Sarjeant, 1992, p.70 (al. 2–222), pl.1, fig.2; pl.2, figs.1–6. Holotype: Quattrocchio and Sarjeant, 1992, pl.2, fig.1. Age: Callovian–late Tithonian.
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Original description: [Quattrocchio and Sarjeant, 1992]:
Dissiliodinium volkheimeri sp. nov.
(Plate 1, Fig. 2; Plate 2, Figs. 1-6)
1987 Dissiliodinium sp. Stover & Helby, p. 27, fig. 16E (without description).
Derivatio Nominis. Named after Dr. Wolfgang Volkheimer, a major pioneer of Argentinian Mesozoic palynology.
Diagnosis. Cysts proximate, subspheroidal, becoming broadly ovoidal when compressed. Autophragm thin, densely and irregularly granulate to verrucate. Sculptural elements low (1 μm or less) and from 0.5 μm to 1.0 μm in diameter. Paratabulation evident only on the epitract and only when the precingular paraplates are separated: paraplates of apical series not differentiated. Archaeopyle precingular (type 5P), the apical paraplates and probably paraplate 6" remaining attached to the hypotract by a sulcal tongue. Paracingulum generally not expressed, although in some specimens it may be indicated by folds. Parasulcus not indicated.
Illustrated specimens. Holotype: 2970/4: 12/141 X (Plate 2, fig. 1): paratype: 2970/1: 19,7/1 45 X (Plate 2, fig. 6); other: 2970/4: 15,6/139,7 X (Plate 2, fig. 2); 2970/4: 5,6/130 X (Plate 2, fig. 3); 2971/4: 11,5/131 X (Plate 2, fig. 4); 2970/4: 11,6/139,9 X (Plate 2, fig. 5); 2970/4: 4,6/115,2 (Plate 1, fig. 2).
Lodgement. Palynological Laboratory, Universidad Nacionaldel Sur, Bahia Blanca.
Dimensions. Holotype: overall length 65 μm, overall breadth 64 μm; paratype: overall length 72 μm; overall breadth 84u m. Range (17 specimens): overall length (with operculum) 63-73 μm; overall length (without operculum) 49-67 μm; overall breadth 47-90 μm.
Horizon. 2970 - 2971 levels.
Locality. Puente delArroyo Picún Leufú.
Remarks. The Argentinian specimens appear to correspond closely with Dissiliodinium sp., illustrated from Australia by Stover & Helby, 1987 (p. 27, fig. 16E) without description.
D. caddaense (Filatoff, 1975) Stover and Helby, 1987 differs in being larger (95 (124)150 μm) and having a persistent antapical bulge or projection. D. globulum Drugg, 1978, differs in being smaller and having a more elaborate ornament, "vaguely spinulose" or approaching a microreticulum; it occurs at a higher horizon and may well be an evolutionary derivative of D. volkheimeri.
Stratigraphic data. The genus Dissiliodinium is known only from the Middle to Upper Jurassic (Bajocian to Early Kimmeridgian).
Dissiliodinium volkheimeri Quattrocchio and Sarjeant, 1992, p.70 (al. 2–222), pl.1, fig.2; pl.2, figs.1–6. Holotype: Quattrocchio and Sarjeant, 1992, pl.2, fig.1. Age: Callovian–late Tithonian.
---------------------------------------------------------------------------------------------------
Original description: [Quattrocchio and Sarjeant, 1992]:
Dissiliodinium volkheimeri sp. nov.
(Plate 1, Fig. 2; Plate 2, Figs. 1-6)
1987 Dissiliodinium sp. Stover & Helby, p. 27, fig. 16E (without description).
Derivatio Nominis. Named after Dr. Wolfgang Volkheimer, a major pioneer of Argentinian Mesozoic palynology.
Diagnosis. Cysts proximate, subspheroidal, becoming broadly ovoidal when compressed. Autophragm thin, densely and irregularly granulate to verrucate. Sculptural elements low (1 μm or less) and from 0.5 μm to 1.0 μm in diameter. Paratabulation evident only on the epitract and only when the precingular paraplates are separated: paraplates of apical series not differentiated. Archaeopyle precingular (type 5P), the apical paraplates and probably paraplate 6" remaining attached to the hypotract by a sulcal tongue. Paracingulum generally not expressed, although in some specimens it may be indicated by folds. Parasulcus not indicated.
Illustrated specimens. Holotype: 2970/4: 12/141 X (Plate 2, fig. 1): paratype: 2970/1: 19,7/1 45 X (Plate 2, fig. 6); other: 2970/4: 15,6/139,7 X (Plate 2, fig. 2); 2970/4: 5,6/130 X (Plate 2, fig. 3); 2971/4: 11,5/131 X (Plate 2, fig. 4); 2970/4: 11,6/139,9 X (Plate 2, fig. 5); 2970/4: 4,6/115,2 (Plate 1, fig. 2).
Lodgement. Palynological Laboratory, Universidad Nacionaldel Sur, Bahia Blanca.
Dimensions. Holotype: overall length 65 μm, overall breadth 64 μm; paratype: overall length 72 μm; overall breadth 84u m. Range (17 specimens): overall length (with operculum) 63-73 μm; overall length (without operculum) 49-67 μm; overall breadth 47-90 μm.
Horizon. 2970 - 2971 levels.
Locality. Puente delArroyo Picún Leufú.
Remarks. The Argentinian specimens appear to correspond closely with Dissiliodinium sp., illustrated from Australia by Stover & Helby, 1987 (p. 27, fig. 16E) without description.
D. caddaense (Filatoff, 1975) Stover and Helby, 1987 differs in being larger (95 (124)150 μm) and having a persistent antapical bulge or projection. D. globulum Drugg, 1978, differs in being smaller and having a more elaborate ornament, "vaguely spinulose" or approaching a microreticulum; it occurs at a higher horizon and may well be an evolutionary derivative of D. volkheimeri.
Stratigraphic data. The genus Dissiliodinium is known only from the Middle to Upper Jurassic (Bajocian to Early Kimmeridgian).