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Eatonicysta exilis
Eatonicysta exilis Pearce, 2010, p.60, pl.3, figs.6–12.
Holotype: Pearce, 2010, pl.3, figs.6–12.
Type locality and horizon. Trunch borehole, Norfolk, UK; 93.9–94.0 m, Paramoudra Chalk, high Belemnitella mucronata Zone (high upper Campanian).
Age: late Campanian–early Maastrichtian.
Diagnosis. A species of Eatonicysta possessing a thin entire ectophragm and six paracingular processes.
Description. Medium-sized chorate dinoflagellate cyst with an ovoidal central body. The body is two-layered with a smooth endophragm and periphragm, the latter of which forms processes that support a thin, loose and entire ectophragm. The processes are intratabular, solid, one per reflected paraplate and of consistent length. They are wide proximally (unconnected), narrowing at the mid-length, before widening and flaring distally. The paratabulation is indicated by intratabular processes that reflect the paraplate formula: 4'?, 6", 6c, 6'", 1p, 1"", 2s? (as, ps). The paracingulum is indicated by an equatorial alignment of processes, and the parasulcus by a deep notch anterior to the anterior sulcal paraplate. The archaeopyle is apical (Type tA, operculum detached) and formed by the loss of all apical paraplates.
Comparison. Differs from Eatonicysta? mutabilireta sp. nov., Eatonicysta ursulae var. a sensu Williams & Downie (1966), Membranilarnacia hapala (Schiøler & Wilson, 1993: 346–347, pl. 2, figs 1–7; text-figs 12a–b) Lachkar & Masure in Fauconnier & Masure (2004) and M. pterococcoides (Wetzel, 1933b: 53, pl. 6, fig. 4) Eisenack, 1963b by possessing paracingular processes. Differs from Eatonicysta ursulae var. b sensu Williams & Downie (1966) by possessing 6 rather than 4 paracingular processes and in possessing an entire ectophragm.
Holotype: Pearce, 2010, pl.3, figs.6–12.
Type locality and horizon. Trunch borehole, Norfolk, UK; 93.9–94.0 m, Paramoudra Chalk, high Belemnitella mucronata Zone (high upper Campanian).
Age: late Campanian–early Maastrichtian.
Diagnosis. A species of Eatonicysta possessing a thin entire ectophragm and six paracingular processes.
Description. Medium-sized chorate dinoflagellate cyst with an ovoidal central body. The body is two-layered with a smooth endophragm and periphragm, the latter of which forms processes that support a thin, loose and entire ectophragm. The processes are intratabular, solid, one per reflected paraplate and of consistent length. They are wide proximally (unconnected), narrowing at the mid-length, before widening and flaring distally. The paratabulation is indicated by intratabular processes that reflect the paraplate formula: 4'?, 6", 6c, 6'", 1p, 1"", 2s? (as, ps). The paracingulum is indicated by an equatorial alignment of processes, and the parasulcus by a deep notch anterior to the anterior sulcal paraplate. The archaeopyle is apical (Type tA, operculum detached) and formed by the loss of all apical paraplates.
Comparison. Differs from Eatonicysta? mutabilireta sp. nov., Eatonicysta ursulae var. a sensu Williams & Downie (1966), Membranilarnacia hapala (Schiøler & Wilson, 1993: 346–347, pl. 2, figs 1–7; text-figs 12a–b) Lachkar & Masure in Fauconnier & Masure (2004) and M. pterococcoides (Wetzel, 1933b: 53, pl. 6, fig. 4) Eisenack, 1963b by possessing paracingular processes. Differs from Eatonicysta ursulae var. b sensu Williams & Downie (1966) by possessing 6 rather than 4 paracingular processes and in possessing an entire ectophragm.