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Tetrachacysta allenii
Tetrachacysta allenii Backhouse, 1988, p.110
Taxonomic junior synonym: Horologinella biconvexa subsp. granulata, according to Xu Jinli et al. (1997, p.42) — however, He Chengquan et al., 2009, p.374) retained that taxon.
Holotype: Backhouse, 1988, pl.42, figs.la–b; text-figs.32B–C; Fensome et al., 1993a, figs.1–2 — p.905.
Locus typicus: Whitfords 4 borehole, Perth Basin, W Australia
Stratum typicum: ?Valanginian-Early Barremian
Original description: Backhouse, 1988, p.110
Cysts small, trilobate, subquadrangular in outline with a paracingular constriction; slightly compressed dorso-ventrally. Hypocyst sometimes wider than epicyst, producing a flask-shaped outline. Autophragm thin, covered by small, regularly spaced truncate or rounded grana, or acicular spines less than 1 µm high and usually less than 0.5 µm wide. Surface features subdued in paracingular zone and sometimes in mid-dorsal and mid-ventral areas. Paratabulation expressed only by archeopyle suture. Archeopyle apical, type [tA], operculum flat, usually free. Archeopyle suture indicating 6 precingular paraplates.
Size: Holotype: length without operculum 35 µm, width of epicyst 31 µm, width of hypocyst 33 µm. Range of 22 specimens: length without operculum 29(37)41 µm, width of epicyst 27(32)34 µm, width of hypocyst 33(38)61 µm.
Taxonomic junior synonym: Horologinella biconvexa subsp. granulata, according to Xu Jinli et al. (1997, p.42) — however, He Chengquan et al., 2009, p.374) retained that taxon.
Holotype: Backhouse, 1988, pl.42, figs.la–b; text-figs.32B–C; Fensome et al., 1993a, figs.1–2 — p.905.
Locus typicus: Whitfords 4 borehole, Perth Basin, W Australia
Stratum typicum: ?Valanginian-Early Barremian
Original description: Backhouse, 1988, p.110
Cysts small, trilobate, subquadrangular in outline with a paracingular constriction; slightly compressed dorso-ventrally. Hypocyst sometimes wider than epicyst, producing a flask-shaped outline. Autophragm thin, covered by small, regularly spaced truncate or rounded grana, or acicular spines less than 1 µm high and usually less than 0.5 µm wide. Surface features subdued in paracingular zone and sometimes in mid-dorsal and mid-ventral areas. Paratabulation expressed only by archeopyle suture. Archeopyle apical, type [tA], operculum flat, usually free. Archeopyle suture indicating 6 precingular paraplates.
Size: Holotype: length without operculum 35 µm, width of epicyst 31 µm, width of hypocyst 33 µm. Range of 22 specimens: length without operculum 29(37)41 µm, width of epicyst 27(32)34 µm, width of hypocyst 33(38)61 µm.