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Manumiella seymourensis
From Fensome et al., 2019:
Manumiella seymourensis Askin 1999, p.373–377, fig.2, nos.1–9; fig.3, nos.1–9. Holotype: Askin 1999, fig.2, no.1. Age: Maastrichtian.
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Original description Askin, 1999
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Supplementary discussion Thorn et al., 2009:
Discussion: The characteristic features of M. seymourensis are the thin, virtually invisible endocyst and the ovoid outline. It has a relatively large intercalary periarcheopyle, commonly with the operculum still attached. The pericyst wall is smooth and relatively thick. On Seymour Island, Manumiella seymourensis is present through much of the López de Bertodano Formation. In this study, its range top is above 870 m in the composite section (approximately 200 m below the KT boundary, Fig. 3). Rare and somewhat torn specimens, which are probably reworked, occur up to 931 m.
The apical and antapical areas of M. seymourensis typically lack horns. These morphotypes are either truncated or rounded, often with dimples; for example, Smith (1992, fig. 7k) and Roncaglia (2000, fig. 5I, p. 141). Rarely specimens exhibit single, nipple-like protrusions (Askin, 1988a, figs. 8.5, 8.6; 1999, figs. 3.1–3.4). In this study, specimens with protrusions are rare compared to perfectly ovoid forms, with no apparent stratigraphical pattern within the López de Bertodano Formation in the occurrence of these morphotypes. The relative rarity of the specimens with protrusions, the overall similarity of the remainder of the pericyst and the lack of any apparent stratigraphical significance to polar development within the material studied suggest that all these variations should not be given subspecific status, and hence are all retained within the specific diagnosis.
Manumiella seymourensis Askin 1999, p.373–377, fig.2, nos.1–9; fig.3, nos.1–9. Holotype: Askin 1999, fig.2, no.1. Age: Maastrichtian.
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Original description Askin, 1999
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Supplementary discussion Thorn et al., 2009:
Discussion: The characteristic features of M. seymourensis are the thin, virtually invisible endocyst and the ovoid outline. It has a relatively large intercalary periarcheopyle, commonly with the operculum still attached. The pericyst wall is smooth and relatively thick. On Seymour Island, Manumiella seymourensis is present through much of the López de Bertodano Formation. In this study, its range top is above 870 m in the composite section (approximately 200 m below the KT boundary, Fig. 3). Rare and somewhat torn specimens, which are probably reworked, occur up to 931 m.
The apical and antapical areas of M. seymourensis typically lack horns. These morphotypes are either truncated or rounded, often with dimples; for example, Smith (1992, fig. 7k) and Roncaglia (2000, fig. 5I, p. 141). Rarely specimens exhibit single, nipple-like protrusions (Askin, 1988a, figs. 8.5, 8.6; 1999, figs. 3.1–3.4). In this study, specimens with protrusions are rare compared to perfectly ovoid forms, with no apparent stratigraphical pattern within the López de Bertodano Formation in the occurrence of these morphotypes. The relative rarity of the specimens with protrusions, the overall similarity of the remainder of the pericyst and the lack of any apparent stratigraphical significance to polar development within the material studied suggest that all these variations should not be given subspecific status, and hence are all retained within the specific diagnosis.