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Impagidinium waipawaense

Impagidinium waipawense Wilson 1988, p.24

NOW Ynezidinium. Originally Impagidinium, subsequently (and now) Ynezidinium.

Holotype: Wilson, 1988, pl.14, figs.1a–c; Fensome et al., 1996, figs.1–3 — p.2439.
Locus typicus: Waipawa Section, Hawkes Bay, New Zealand
Stratum typicum: Early-Middle Eocene (Mangaorapan-Porangan)

Original description: Wilson, 1988, p. 24
Cyst subspherical, of intermediate size; autophragm characterised by perforate parasutural septa and smooth intratabular areas. Septa fairly prominent (height up to 4 µm) perforate (perforations 1-3 µm) and generally smooth crested; base of septa relatively broad (up to 3 µm) and may be bordered by narrow perforate zone. Horn short (length 6 µm) broad based (breadth up to 10 µm), somewhat perforate, with an irregular blunt apex. Paratabulation well defined by septa, gonyaulacacean, formula 4", 6"", 6c, 1p, 1"""", 2-3s. Archeopyle relatively small (length 14 µm, breadth 17 µm on holotype) Type P; operculum free. Paracingulum indicated by parallel, transverse ridges (breadth up to 8 µm) and usually comprises 6 paraplates. Parasulcus extends to epicyst and is somewhat broader on hypocyst; up to three small sulcal paraplates present. Dimensions: Holotype: overall length 68µm, breadth 61µm, length of horn 10 µm. Range: length (including horn) 56 (68) 83 µm, breadth 49 (60) 78 µm, horn 6 µm (n= 10).

Affinities:
Wilson, 1988, p. 24: Impagidinium waipawaense differs from previously described species of Impagidinium chiefly in the nature of the parasutural septa which are characteristically perforate.
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