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Turbiosphaera guersteiniae
Turbiosphaera guersteiniae Bijl and Brinkhuis, 2015, p.91–92, pl.1A–G.
Holotype: Bijl and Brinkhuis, 2015, pl.1A–B.
Age: Ypresian.
Original description (Bijl and Brinkhuis, 2015):
Turbiosphaera guersteinae sp. nov. Plate I, A–G
Holotype: IODP Hole U1356A-103R-1 W, 90–92 cm Slide 1, England Finder coordinates U58-4. Plate I; A, B
Paratype: IODP Hole U1356A-103R-1 W, 130–132 cm Slide 2, England Finder coordinates F42. Plate I; D, E
Type locality:Lower Eocene of IODP Hole U1356A, Wilkes Land Margin, Antarctica. Lithological unit XI (Escutia et al., 2011).
Etymology: The species name was erected in recognition of the work of Dr. G. Raquel Guerstein, for her work on organic-walled dinocyst taxonomy and paleoecology in Argentina.
Synonymy:Cordosphaeridium sp. A (Bijl et al., 2013b) plate VII, m
Diagnosis: A relatively small species of Turbiosphaera characterized by a typical long, slender, solid, fibrous, antapical process and large, thick, solid, fibrous, processes marking the post- and precingular plates which end in a solid, non-fibrous, smooth, bulbous, slightly doming distal edge. Cingular processes are rectangular, shelf-like. All processes are disconnected distally.
Dimensions:
Holotype cyst body (excluding processes): 48.6 × 40.0 μm (length (l) × width (w)); including processes: 82.9 × 57.1 μm (l × w).
Paratype cyst body (excluding processes): 68.6 × 61.4 μm (l × depth (d)); including processes: 68.6 × 61.4 μm (l × d).
Average dimensions (n = 10) cyst body (excluding processes): 51.1 (42.9–61.4) × 38.6 (25.7–45.7) × 41.4 (34.3–48.6) μm (l × w × d); including processes: 83.6 (68.6–108.6) × 55.2 (37.1–65.7) × 55.0 (51.4–61.4) μm (l × w × d).
Description: A cyst with two wall layers, which are closely appressed between processes. The central, inner cyst wall is oval, longer than wide. The outer wall is fibrous and gives rise to disconnected intratabular processes marking all plates, including the cingular and sulcal plates. The size of the processes varies relative to plate size. The stems of processes rising up from pre- and postcingular plates are fibrous, perforate, solid and broad, and end distally into a smooth, non-perforate, slightly doming surface. The process marking the antapical plate is longer than the other processes (about a third of the total length of the cyst), fibrous and perforate, slender. The cingular processes are rectangular, shelf-like. Dorsal plate configuration indicates dextral torsion. Archeopyle precingular type P, indicated by the loss of 3″. Plate configuration 4′, 6″, 6c, 4s, 1p, 6‴, 1‴′.
Stratigraphic distribution: The stratigraphic range of Turbiosphaera guersteinae sp. nov. in the type material is relatively short and well constrained by magnetostratigraphy ( Tauxe et al., 2012; Bijl et al., 2013b ; Bijl et al., 2014). The first occurrence is between sample U1356A-104R-2 W, 40–42 cm (979.47 mbsf) and 50–52 cm (979.57 mbsf), correlating to mid-magnetochron C24n.1r. The species occurs consistently (i.e. in almost every available sample), albeit in low relative abundance, until its last occurrence between samples U1356A-103R-1 W, 20–22 cm (968.21 mbsf) and 10–12 cm (968.11 mbsf), correlating to mid-chron C24n.1n ( Tauxe et al., 2012; Bijl et al., 2013b ; Bijl et al., 2014). In the Geomagnetic Polarity Time Scale of Vandenberghe et al. (2012) this equates to an age-range between 53.1 and 52.9 Ma.
Geographic distribution: To date, Turbiosphaera guersteinae has only been recognized in the type section.
Comparison: Turbiosphaera guersteinae sp. nov. differs from Turbiosphaera filosa in lacking distal connections of processes, lacking additional fine processes and has a characteristic fibrous process stems while the distal ends of the processes are solid. Turbiosphaera guersteinae differs from species of Cordosphaeridium e.g., Cordosphaeridium fibrospinosum Davey and Williams, 1966, Cordosphaeridium cantharellus ( Brosius, 1963) Gocht, 1969, Cordosphaeridium funiculatum Morgenroth, 1966 and Cordosphaeridium gracile ( Eisenack, 1954) Davey and Williams, 1966 in having processes that terminate in a solid, doming distal surface rather than a flared distal end. In the type material, T. guersteinae sp. nov. is relatively small and thin-walled, giving it a more transparent appearance.
Holotype: Bijl and Brinkhuis, 2015, pl.1A–B.
Age: Ypresian.
Original description (Bijl and Brinkhuis, 2015):
Turbiosphaera guersteinae sp. nov. Plate I, A–G
Holotype: IODP Hole U1356A-103R-1 W, 90–92 cm Slide 1, England Finder coordinates U58-4. Plate I; A, B
Paratype: IODP Hole U1356A-103R-1 W, 130–132 cm Slide 2, England Finder coordinates F42. Plate I; D, E
Type locality:Lower Eocene of IODP Hole U1356A, Wilkes Land Margin, Antarctica. Lithological unit XI (Escutia et al., 2011).
Etymology: The species name was erected in recognition of the work of Dr. G. Raquel Guerstein, for her work on organic-walled dinocyst taxonomy and paleoecology in Argentina.
Synonymy:Cordosphaeridium sp. A (Bijl et al., 2013b) plate VII, m
Diagnosis: A relatively small species of Turbiosphaera characterized by a typical long, slender, solid, fibrous, antapical process and large, thick, solid, fibrous, processes marking the post- and precingular plates which end in a solid, non-fibrous, smooth, bulbous, slightly doming distal edge. Cingular processes are rectangular, shelf-like. All processes are disconnected distally.
Dimensions:
Holotype cyst body (excluding processes): 48.6 × 40.0 μm (length (l) × width (w)); including processes: 82.9 × 57.1 μm (l × w).
Paratype cyst body (excluding processes): 68.6 × 61.4 μm (l × depth (d)); including processes: 68.6 × 61.4 μm (l × d).
Average dimensions (n = 10) cyst body (excluding processes): 51.1 (42.9–61.4) × 38.6 (25.7–45.7) × 41.4 (34.3–48.6) μm (l × w × d); including processes: 83.6 (68.6–108.6) × 55.2 (37.1–65.7) × 55.0 (51.4–61.4) μm (l × w × d).
Description: A cyst with two wall layers, which are closely appressed between processes. The central, inner cyst wall is oval, longer than wide. The outer wall is fibrous and gives rise to disconnected intratabular processes marking all plates, including the cingular and sulcal plates. The size of the processes varies relative to plate size. The stems of processes rising up from pre- and postcingular plates are fibrous, perforate, solid and broad, and end distally into a smooth, non-perforate, slightly doming surface. The process marking the antapical plate is longer than the other processes (about a third of the total length of the cyst), fibrous and perforate, slender. The cingular processes are rectangular, shelf-like. Dorsal plate configuration indicates dextral torsion. Archeopyle precingular type P, indicated by the loss of 3″. Plate configuration 4′, 6″, 6c, 4s, 1p, 6‴, 1‴′.
Stratigraphic distribution: The stratigraphic range of Turbiosphaera guersteinae sp. nov. in the type material is relatively short and well constrained by magnetostratigraphy ( Tauxe et al., 2012; Bijl et al., 2013b ; Bijl et al., 2014). The first occurrence is between sample U1356A-104R-2 W, 40–42 cm (979.47 mbsf) and 50–52 cm (979.57 mbsf), correlating to mid-magnetochron C24n.1r. The species occurs consistently (i.e. in almost every available sample), albeit in low relative abundance, until its last occurrence between samples U1356A-103R-1 W, 20–22 cm (968.21 mbsf) and 10–12 cm (968.11 mbsf), correlating to mid-chron C24n.1n ( Tauxe et al., 2012; Bijl et al., 2013b ; Bijl et al., 2014). In the Geomagnetic Polarity Time Scale of Vandenberghe et al. (2012) this equates to an age-range between 53.1 and 52.9 Ma.
Geographic distribution: To date, Turbiosphaera guersteinae has only been recognized in the type section.
Comparison: Turbiosphaera guersteinae sp. nov. differs from Turbiosphaera filosa in lacking distal connections of processes, lacking additional fine processes and has a characteristic fibrous process stems while the distal ends of the processes are solid. Turbiosphaera guersteinae differs from species of Cordosphaeridium e.g., Cordosphaeridium fibrospinosum Davey and Williams, 1966, Cordosphaeridium cantharellus ( Brosius, 1963) Gocht, 1969, Cordosphaeridium funiculatum Morgenroth, 1966 and Cordosphaeridium gracile ( Eisenack, 1954) Davey and Williams, 1966 in having processes that terminate in a solid, doming distal surface rather than a flared distal end. In the type material, T. guersteinae sp. nov. is relatively small and thin-walled, giving it a more transparent appearance.