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Impagidinium cassiculus
From Fensome et al., 2019:
Impagidinium cassiculum Wilson, 1988, p.23, pl.13, figs.2a–b,3,5a–b. Holotype: Wilson, 1988, pl.13, fig.3; Fensome et al., 1996, fig.3 — p.2085. NIA. Age: Early Eocene.
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Locus typicus: Waipawa Section, Hawkes Bay,New Zealand
Stratum typicum: Waipawan Stage, Early Eocene
Original description: Wilson, 1988, p. 23
Cyst of intermediate size, subspherical to ovoidal; autophragm fairly thick (up to 2 µm) coarsely reticulate (lumen up to 6 µm), the reticulation being best defined near the paraplate margins. Parasutural septa somewhat irregular in shape and often chain-like (height up to 4 µm). Paratabulation defined by septa, reasonably clear on dorsal surface, somewhat poorly defined and masked by surface reticulation on ventral surface. Formula apparently 4', 6'', Xc, 5''', 1p, 1'''', ?s; no clear definition of sulcal paraplates. Parasulcus somewhat elongate and relatively smooth. paracingulum relatively well defined by sub-parallel septa (breadth up to 7 µm) and usually segmented into 5 or 6 cingular paraplates. Archeopyle relatively large, sub-pentagonal, somewhat rounded; operculum distinctive, reticulate near margin, relatively smooth near centre. An irregular membranous apical horn or protrusion usually present (length up to 12 µm). Dimensions Holotype: overall length 86 µm, breadth 77 µm. Range: length 54(72)95 µm, breadth 56(64)81 µm (n = 20).
Affinities:
Wilson, 1988, p. 23: The species is distinguished from other species of Impagidinium chiefly by its coarsely reticulate periphragm and chain-like irregular parasutural septa. It differs from species of Corrudinium in being larger and in generally having an apical horn or protrusion.
Impagidinium cassiculum Wilson, 1988, p.23, pl.13, figs.2a–b,3,5a–b. Holotype: Wilson, 1988, pl.13, fig.3; Fensome et al., 1996, fig.3 — p.2085. NIA. Age: Early Eocene.
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Locus typicus: Waipawa Section, Hawkes Bay,New Zealand
Stratum typicum: Waipawan Stage, Early Eocene
Original description: Wilson, 1988, p. 23
Cyst of intermediate size, subspherical to ovoidal; autophragm fairly thick (up to 2 µm) coarsely reticulate (lumen up to 6 µm), the reticulation being best defined near the paraplate margins. Parasutural septa somewhat irregular in shape and often chain-like (height up to 4 µm). Paratabulation defined by septa, reasonably clear on dorsal surface, somewhat poorly defined and masked by surface reticulation on ventral surface. Formula apparently 4', 6'', Xc, 5''', 1p, 1'''', ?s; no clear definition of sulcal paraplates. Parasulcus somewhat elongate and relatively smooth. paracingulum relatively well defined by sub-parallel septa (breadth up to 7 µm) and usually segmented into 5 or 6 cingular paraplates. Archeopyle relatively large, sub-pentagonal, somewhat rounded; operculum distinctive, reticulate near margin, relatively smooth near centre. An irregular membranous apical horn or protrusion usually present (length up to 12 µm). Dimensions Holotype: overall length 86 µm, breadth 77 µm. Range: length 54(72)95 µm, breadth 56(64)81 µm (n = 20).
Affinities:
Wilson, 1988, p. 23: The species is distinguished from other species of Impagidinium chiefly by its coarsely reticulate periphragm and chain-like irregular parasutural septa. It differs from species of Corrudinium in being larger and in generally having an apical horn or protrusion.