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Evittosphaerula foraminosa
From Fensome et al., 2019:
Evittosphaerula? foraminosa Fensome et al., 2016b, p.44, pl.6, figs.15–20. Holotype: Fensome et al., 2016b, pl.6, figs.19–20. Questionable assignment: Fensome et al. (2016b, p.44) Age: holotype Ypresian.
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Original description Fensome et al., 2016b:
Holotype. Plate 6, figs 19, 20 from a cuttings sample at 2130–2140 m in North Leif I-05, GSC type collection no. 138159, sample YD17600, slide 03, co-ordinates 44.9 × 15.5, England Finder M43/0. Pericyst length 82.5 μm, width 90 μm. The age determined for the sample from which the holotype was recovered is Ypresian.
Etymology. From the Latin foraminosus, meaning ‘full of holes’.
Description. A species of gonyaulacalean cysts in which only broad strips of membrane representing the sutures are preserved. The tabulation appears to be goniodomaceans, with a five-sided antapical plate reflecting a quinqueform hypocystal tabulation. At the apex, sutural strips come together to form a short apical horn.
Size. Diameter 68–90 μm; four specimens in dorsoventral orientation measured, but excluding the holotype as it is oriented apically–antapically.
Age. LO: Ypresian.
Remarks. This species has a very distinctive structure, represented by strips of membrane reflecting the sutures only; the internal area of each plate is represented by a hole. Thus the species is reminiscent of the late Oligocene to early Miocene species Evittospaherula paratabulata, but differs superficially in having an apical horn, an apparently much narrower cingulum, and broader sutural membranes. More fundamentally, one specimen (Plate 6, fig. 18) appears to have a five-sided antapical plate, suggesting a goniodomacean affinity (Fensome et al. 1993). The tabulation described by Manum (1979) for Evittosphaerula paratabulata, the type of the genus, is clearly gonyaulacacean. As this new species is strikingly similar, albeit perhaps superficially, to Manum’s species, and there is not sufficient material to describe its tabulation in full, it is questionably assigned to Evittosphaerula. The new species is also strikingly similar to both Hapsocysta susanae, described by Duxbury (2002) from the Albian of the central North Sea, and Chaenosphaerula magnifica, described by Damassa (1997) from the late Oligocene of the Norwegian Sea. However, the tabulation of both those species is clearly sexiform, and neither has horns.
Evittosphaerula? foraminosa Fensome et al., 2016b, p.44, pl.6, figs.15–20. Holotype: Fensome et al., 2016b, pl.6, figs.19–20. Questionable assignment: Fensome et al. (2016b, p.44) Age: holotype Ypresian.
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Original description Fensome et al., 2016b:
Holotype. Plate 6, figs 19, 20 from a cuttings sample at 2130–2140 m in North Leif I-05, GSC type collection no. 138159, sample YD17600, slide 03, co-ordinates 44.9 × 15.5, England Finder M43/0. Pericyst length 82.5 μm, width 90 μm. The age determined for the sample from which the holotype was recovered is Ypresian.
Etymology. From the Latin foraminosus, meaning ‘full of holes’.
Description. A species of gonyaulacalean cysts in which only broad strips of membrane representing the sutures are preserved. The tabulation appears to be goniodomaceans, with a five-sided antapical plate reflecting a quinqueform hypocystal tabulation. At the apex, sutural strips come together to form a short apical horn.
Size. Diameter 68–90 μm; four specimens in dorsoventral orientation measured, but excluding the holotype as it is oriented apically–antapically.
Age. LO: Ypresian.
Remarks. This species has a very distinctive structure, represented by strips of membrane reflecting the sutures only; the internal area of each plate is represented by a hole. Thus the species is reminiscent of the late Oligocene to early Miocene species Evittospaherula paratabulata, but differs superficially in having an apical horn, an apparently much narrower cingulum, and broader sutural membranes. More fundamentally, one specimen (Plate 6, fig. 18) appears to have a five-sided antapical plate, suggesting a goniodomacean affinity (Fensome et al. 1993). The tabulation described by Manum (1979) for Evittosphaerula paratabulata, the type of the genus, is clearly gonyaulacacean. As this new species is strikingly similar, albeit perhaps superficially, to Manum’s species, and there is not sufficient material to describe its tabulation in full, it is questionably assigned to Evittosphaerula. The new species is also strikingly similar to both Hapsocysta susanae, described by Duxbury (2002) from the Albian of the central North Sea, and Chaenosphaerula magnifica, described by Damassa (1997) from the late Oligocene of the Norwegian Sea. However, the tabulation of both those species is clearly sexiform, and neither has horns.