Back
Gardodinium lowii
Gardodinium lowii Backhouse, 1987
Holotype: Backhouse, 1987, fig.10G; Fensome et al., 1996, fig.1 — p.2209.
Locus typicus: Perth Basin, Australia
Stratum typicum: Middle Hauterivian
Original description: Backhouse, 1987, p. 216
Cyst holocavate, elongate ovoidal in shape, with a long apical horn. Autophragm with rounded antapex; apex drawn into a long, distally closed, apical protrusion 18-34 µm long. Fine, solid spines 1-4 µm long, evenly distributed over the autophragm, longest beneath paracingular ridges and at apex, supporting a membranous ectophragm. Ectophragm forming a long, hollow, distally open, apical horn projecting 8-15 µm beyond the tip of the horn formed by the autophragm. Paracingulum weakly expressed by low ridges on the ectophragm, possibly slightly offset. Parasulcus not discernible. Archeopyle apical, type [tA]. Operculum frequently adherent. Paratabulation indicated only by the archeopyle suture indicating 4 apical paraplates and 5 or 6 precingular paraplates.
Dimensions. Total length of holotype 106 µm, width 41 µm. Range of total length (12 specimens) 85(102)116 µm, width 33(39)46 µm.
Affinities:
Backhouse, 1987, p. 216: Gardodinium lowii is more elongate than other species of the genus and in particular is distinguished by its long apical horn. In other respects it is similar to G. trabeculosum. Forms with a rather shorter apical horn which occur in the K. scrutillinum Zone are assigned to C. attenuatum Stover & Helby (this memoir a). Davey"s (1978) view, supported by Duxbury (1983), that Gardodinium is a junior synonym of Chlamydophorella Cookson & Eisenack 1958 is not followed here. Gardodinium exhibits a hollow ectophragmal apical horn, a feature not shown by the genotype of Chlamydophorella.
Holotype: Backhouse, 1987, fig.10G; Fensome et al., 1996, fig.1 — p.2209.
Locus typicus: Perth Basin, Australia
Stratum typicum: Middle Hauterivian
Original description: Backhouse, 1987, p. 216
Cyst holocavate, elongate ovoidal in shape, with a long apical horn. Autophragm with rounded antapex; apex drawn into a long, distally closed, apical protrusion 18-34 µm long. Fine, solid spines 1-4 µm long, evenly distributed over the autophragm, longest beneath paracingular ridges and at apex, supporting a membranous ectophragm. Ectophragm forming a long, hollow, distally open, apical horn projecting 8-15 µm beyond the tip of the horn formed by the autophragm. Paracingulum weakly expressed by low ridges on the ectophragm, possibly slightly offset. Parasulcus not discernible. Archeopyle apical, type [tA]. Operculum frequently adherent. Paratabulation indicated only by the archeopyle suture indicating 4 apical paraplates and 5 or 6 precingular paraplates.
Dimensions. Total length of holotype 106 µm, width 41 µm. Range of total length (12 specimens) 85(102)116 µm, width 33(39)46 µm.
Affinities:
Backhouse, 1987, p. 216: Gardodinium lowii is more elongate than other species of the genus and in particular is distinguished by its long apical horn. In other respects it is similar to G. trabeculosum. Forms with a rather shorter apical horn which occur in the K. scrutillinum Zone are assigned to C. attenuatum Stover & Helby (this memoir a). Davey"s (1978) view, supported by Duxbury (1983), that Gardodinium is a junior synonym of Chlamydophorella Cookson & Eisenack 1958 is not followed here. Gardodinium exhibits a hollow ectophragmal apical horn, a feature not shown by the genotype of Chlamydophorella.