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Turbiosphaera sagena
From Fensome et al., 2019:
Turbiosphaera sagena Levy and Harwood, 2000, p.230, pl.11, figs.a–e.
Holotype: Levy and Harwood, 2000, pl.11, figs.a–c.
Age: early Late Eocene.
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Original description (Levy and Harwood, 2000):
Turbiosphaera sagena n. sp. Plate 11, figs. a-e
Turbiosphaera filosa sensu Kemp, 1975, Plate 3, Figures 1 and2.
Turbiosphaera sp. a Crouch & Hollis, 1996, Plate 7, Figure 6.
Derivation of name. Latin, sagena, fish-net, with reference to the fine network of fibrous strands that connect the processes.
Holotype. Plate 11, Figures a-c. UNSM PB99-07: Sample MB 181(2), slide 1, middle to upper Eocene erratic, McMurdo Sound, Antarctica.
Description. Shape: A chordate dinoflagellate cyst with solid to fibrous intratabular processes. Central body is elongate to sub-spherical. Phragma: The central body consists of a thick walled, fibrous autophragm. Processes are usually distally connected by fibrous, discontinuous strands or trabeculae. However, cingular processes are only rarely connected to precingular processes which separates the network of fine strands in the epicyst from the network in the hypocyst. Paratabulation: Indicated by the intratabular processes and process complexes. Paratabulation appears to be gonyaulacacean hexiform, 4', 5-6(?)", 6c, 6(?)'", 1’’’’. Paracingulum: Parasutural fibrous processes indicate the position of the paracingulum. The processes are joined distally creating a hollow enclosed space across the paracingulum. These connected processes form the shelf-like projections typical of Turbiosphaera. The paracingulum is laevorotatory, offset by 1 Parasulcus: The surface ornamentation within the parasulcus appears less fibrous than the rest of the cyst. Projections consist of low fibrous ridges and short fine processes. A break in the cingulum occurs at the anterior margin of the parasulcus. Archeopyle: The archeopyle is formed by the complete removal of the 3" precingular paraplate. Type P (3").
Dimensions. Observed range (three specimens): Central body length - 75 to 81 µm (mean 78 µm), central body width - 53 to 66 µm (mean 61 µm); total length - 130 to 147 µm (mean 139 µm), total width- 83 to 118 µm (mean 97 µm).
Comments/comparison. The epicystal processes and hypocystal processes on specimens of Turbiosphaera sagena are joined distally by a fine network of fibrous strands. The paracingular processes are often hollow, formed by fine penitabular septa that are joined distally. The fibrous ectophragm distinguishes Turbiosphaera sagena from T. filosa. Species of Araneosphaera have processes that are joined distally, however, these processes are restricted to the hypocyst.
Stratigraphic Range. Turbiosphaera sagena is reported from the lower upper Eocene of DSDP Hole 281 by Crouch and Hollis (1996) (as Turbiosphaera. sp. a)
Turbiosphaera sagena Levy and Harwood, 2000, p.230, pl.11, figs.a–e.
Holotype: Levy and Harwood, 2000, pl.11, figs.a–c.
Age: early Late Eocene.
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Original description (Levy and Harwood, 2000):
Turbiosphaera sagena n. sp. Plate 11, figs. a-e
Turbiosphaera filosa sensu Kemp, 1975, Plate 3, Figures 1 and2.
Turbiosphaera sp. a Crouch & Hollis, 1996, Plate 7, Figure 6.
Derivation of name. Latin, sagena, fish-net, with reference to the fine network of fibrous strands that connect the processes.
Holotype. Plate 11, Figures a-c. UNSM PB99-07: Sample MB 181(2), slide 1, middle to upper Eocene erratic, McMurdo Sound, Antarctica.
Description. Shape: A chordate dinoflagellate cyst with solid to fibrous intratabular processes. Central body is elongate to sub-spherical. Phragma: The central body consists of a thick walled, fibrous autophragm. Processes are usually distally connected by fibrous, discontinuous strands or trabeculae. However, cingular processes are only rarely connected to precingular processes which separates the network of fine strands in the epicyst from the network in the hypocyst. Paratabulation: Indicated by the intratabular processes and process complexes. Paratabulation appears to be gonyaulacacean hexiform, 4', 5-6(?)", 6c, 6(?)'", 1’’’’. Paracingulum: Parasutural fibrous processes indicate the position of the paracingulum. The processes are joined distally creating a hollow enclosed space across the paracingulum. These connected processes form the shelf-like projections typical of Turbiosphaera. The paracingulum is laevorotatory, offset by 1 Parasulcus: The surface ornamentation within the parasulcus appears less fibrous than the rest of the cyst. Projections consist of low fibrous ridges and short fine processes. A break in the cingulum occurs at the anterior margin of the parasulcus. Archeopyle: The archeopyle is formed by the complete removal of the 3" precingular paraplate. Type P (3").
Dimensions. Observed range (three specimens): Central body length - 75 to 81 µm (mean 78 µm), central body width - 53 to 66 µm (mean 61 µm); total length - 130 to 147 µm (mean 139 µm), total width- 83 to 118 µm (mean 97 µm).
Comments/comparison. The epicystal processes and hypocystal processes on specimens of Turbiosphaera sagena are joined distally by a fine network of fibrous strands. The paracingular processes are often hollow, formed by fine penitabular septa that are joined distally. The fibrous ectophragm distinguishes Turbiosphaera sagena from T. filosa. Species of Araneosphaera have processes that are joined distally, however, these processes are restricted to the hypocyst.
Stratigraphic Range. Turbiosphaera sagena is reported from the lower upper Eocene of DSDP Hole 281 by Crouch and Hollis (1996) (as Turbiosphaera. sp. a)