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Pareodinia magna
From Fensome et al., 2019:
Pareodinia magna Duxbury, 2018, p.188–189, pl.10, figs.1–5; text-fig.7. Holotype: Duxbury, 2018, pl.10, fig.1–2. Age: early Valanginian.
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Original description Duxbury, 2018:
Plate 10, Figures 1, 2.
Type Locality: Well 20/01-8 at 6883.30ft (conventional core
chip), lower Valanginian. Holotype: E.F. L42.2.
Derivation of Name: From the Latin magnus, large, great – in reference to the very large size of this species.
Diagnosis: An unusually large, fairly thick-walled species, elongate but broad for the genus and with a long, tapering, distally-rounded apical horn. The cyst surface is smooth and unornamented, and the archeopyle involves the displacement of two intercalary plates.
Dimensions: Holotype: Body length – 142 μm.Width – 89 μm.
Overall: Length – 142 (116) 101μm. Width – 89 (70) 61μm.
Specimens Measured: 22.
Remarks: Pareodinia magna n. sp. is characterised by its large size and relatively wide girth. In this and in the general body shape, it is similar to Gochteodinia parvispina n. sp. and G. scytala n. sp., differing mainly in lacking ornament. It has been assigned to Pareodinia Deflandre 1947 here because of its typically. pareodinioid shape and its lack of ornament.
The archeopyle type in Pareodinia magna Duxbury n. sp., Gochteodinia parvispina n. sp. and G. scytala n. sp. appears to be 2-plate intercalary, with apparently homologous plates displaced in each (Plate 10, Figures 2, 13, 20, text-figure 7). If a lineage from G. scytala n. sp. to P. magna n. sp. might be inferred, this similarity of archeopyle type might be expected.
Fensome et al. 1993 (text-fig. 79) suggest differing dorsal plate configurations in Gochteodinia and Pareodinia, so that the first possesses two pentagonal intercalary plates, whereas the last has three intercalaries consisting of a central hexagonal plate flanked by two which are four-sided. Although it has not been possible here to determine the exact shapes of the opercular plates in Pareodinia magna n. sp., their angularity suggests that both are at least 5 sided (Plate 10, Figure 2, text-figure 7), conforming to the model presented for Gochteodinia by Fensome et al. (1993, text-figures 78 E-G and 79 F). This, and the possibility that Pareodinia magna represents an ornament-free end point of a series of otherwise similar taxa, suggests that it might better be described as a smooth Gochteodinia.
Pareodinia magna Duxbury, 2018, p.188–189, pl.10, figs.1–5; text-fig.7. Holotype: Duxbury, 2018, pl.10, fig.1–2. Age: early Valanginian.
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Original description Duxbury, 2018:
Plate 10, Figures 1, 2.
Type Locality: Well 20/01-8 at 6883.30ft (conventional core
chip), lower Valanginian. Holotype: E.F. L42.2.
Derivation of Name: From the Latin magnus, large, great – in reference to the very large size of this species.
Diagnosis: An unusually large, fairly thick-walled species, elongate but broad for the genus and with a long, tapering, distally-rounded apical horn. The cyst surface is smooth and unornamented, and the archeopyle involves the displacement of two intercalary plates.
Dimensions: Holotype: Body length – 142 μm.Width – 89 μm.
Overall: Length – 142 (116) 101μm. Width – 89 (70) 61μm.
Specimens Measured: 22.
Remarks: Pareodinia magna n. sp. is characterised by its large size and relatively wide girth. In this and in the general body shape, it is similar to Gochteodinia parvispina n. sp. and G. scytala n. sp., differing mainly in lacking ornament. It has been assigned to Pareodinia Deflandre 1947 here because of its typically. pareodinioid shape and its lack of ornament.
The archeopyle type in Pareodinia magna Duxbury n. sp., Gochteodinia parvispina n. sp. and G. scytala n. sp. appears to be 2-plate intercalary, with apparently homologous plates displaced in each (Plate 10, Figures 2, 13, 20, text-figure 7). If a lineage from G. scytala n. sp. to P. magna n. sp. might be inferred, this similarity of archeopyle type might be expected.
Fensome et al. 1993 (text-fig. 79) suggest differing dorsal plate configurations in Gochteodinia and Pareodinia, so that the first possesses two pentagonal intercalary plates, whereas the last has three intercalaries consisting of a central hexagonal plate flanked by two which are four-sided. Although it has not been possible here to determine the exact shapes of the opercular plates in Pareodinia magna n. sp., their angularity suggests that both are at least 5 sided (Plate 10, Figure 2, text-figure 7), conforming to the model presented for Gochteodinia by Fensome et al. (1993, text-figures 78 E-G and 79 F). This, and the possibility that Pareodinia magna represents an ornament-free end point of a series of otherwise similar taxa, suggests that it might better be described as a smooth Gochteodinia.