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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).
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Emended description Guerstein et al., 2023:
Emended diagnosis: A species of Turbiosphaera characterised by individual intratabular to penitabular taeniate processes; each process has a variable number of fibrous slender stems united distally by thick perforated platforms (Plate III, 12, arrowed in white). These platforms may be occasionally joined with those of adjacent processes, but the processes are not usually connected along their length. Isolated cingular processes are also taeniate but short and shelf-like.
Dimensions: Total length 70–135 μm (20 specimens measured); total width 52–100 μm; central body length 46–80 μm; central body width 40–70 μm; archaeopyle 23–35 μm (8 specimens measured); processes length 5–40 μm (20 specimens measured).
Remarks and comparisons: Levy and Harwood (2000) described Turbiosphaera sagena from the McMurdo Erratics in East Antarctica. They pointed out that the epicystal processes and hypocystal processes are joined distally by a fine network of fibrous strands. As in the type material, in our specimens it is easy to see that the epicystal and hypocystal processes are occasionally joined distally (Plate III, 11–12). This feature distinguishes Turbiosphaera sagena from Turbiosphaera filosa (Levy and Harwood, 2000). The specimens we observed in the Río Turbio and Loreto formations have processes formed by groups of fibrous stems distally joined by thick perforated platforms (Plate III, 11–12), which sometimes but not always overlap with adjacent processes (Plate II, 4–5). Processes on the hypocyst are longer than those on the epicyst. Processes in Turbiosphaera sagena are longer and more individually developed than in Turbiosphaera archangelskyi, the processes of which do not have distal platforms and are joined along their length and linked distally by a trabecular network, with trabecula thicker than those of Turbiosphaera sagena.
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).
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Emended description Guerstein et al., 2023:
Emended diagnosis: A species of Turbiosphaera characterised by individual intratabular to penitabular taeniate processes; each process has a variable number of fibrous slender stems united distally by thick perforated platforms (Plate III, 12, arrowed in white). These platforms may be occasionally joined with those of adjacent processes, but the processes are not usually connected along their length. Isolated cingular processes are also taeniate but short and shelf-like.
Dimensions: Total length 70–135 μm (20 specimens measured); total width 52–100 μm; central body length 46–80 μm; central body width 40–70 μm; archaeopyle 23–35 μm (8 specimens measured); processes length 5–40 μm (20 specimens measured).
Remarks and comparisons: Levy and Harwood (2000) described Turbiosphaera sagena from the McMurdo Erratics in East Antarctica. They pointed out that the epicystal processes and hypocystal processes are joined distally by a fine network of fibrous strands. As in the type material, in our specimens it is easy to see that the epicystal and hypocystal processes are occasionally joined distally (Plate III, 11–12). This feature distinguishes Turbiosphaera sagena from Turbiosphaera filosa (Levy and Harwood, 2000). The specimens we observed in the Río Turbio and Loreto formations have processes formed by groups of fibrous stems distally joined by thick perforated platforms (Plate III, 11–12), which sometimes but not always overlap with adjacent processes (Plate II, 4–5). Processes on the hypocyst are longer than those on the epicyst. Processes in Turbiosphaera sagena are longer and more individually developed than in Turbiosphaera archangelskyi, the processes of which do not have distal platforms and are joined along their length and linked distally by a trabecular network, with trabecula thicker than those of Turbiosphaera sagena.