Back
Samlandia carnarvonensis
Samlandia carnarvonensis McMinn, 1988, p.150, figs.7A-C.
Holotype: McMinn, 1988, figs.7A-C; Fensome et al., 1996, figs.1-3 - p.2081.
Age: Late Campanian-Early Maastrichtian.
Original description (McMinn, 1988)
Description. Proximate, subspherical to ellipsoidal cyst. The wall is composed of three layers; an endophragm, a periphragm and an ectophragm. The endophragm is 2-3 µm thick and smooth to finely granulate. The periphragm is 0.5 µm thick and developed into a reticulum with cell widths up to 8 µm and
a height up to 2 µm. Lumina are ovaI to polygonal. The endophragm and periphragm are closely appressed while the ectophragm is supported by the walls of the reticulum. A short apical horn, formed by an extension of the periphragm and ectophragm, is usually present. The archeopyle is precingular, type P (3" only), and the operculum is normally free. There is no indication of a parasulcus or a paracingulum.
Size. Pericyst (excluding reticulum); length 64(61)54 µm, width 61(54)50 µm. Twenty specimens were measured.
Comparison. Samlandia carnarvonensis resembles the Late Eocene species Samlandia reticulifera Cookson & Eisenack 1965. It is distinguished by its lower, finer reticulum and the absence of distinctly higher ornament around the equator and at the antapex. The presence of a reticulum aIso distinguishes Samlandia carnarvonensis from the other Late Cretaceous species Samlandia mayi sp. nov. and Samlandia vermicutaria sp. nov. S. carnarvonensis is similar to Deflandrea extrema Cookson & Eisenack 1974, but the description and illustration of the type of the latter do not allow a closer comparison. The type locality of Deflandrea extrema, however, is from a Turonian sequence in Balcatta-1 bore, whereas Samlandia carnarvonensis has a late Campanian to early Maastrichtian range. The two species, therefore, apparently
have distinct and separate stratigraphic ranges.
Type material. Holotype, Fig. 7A-C; F47024, Wapet Rough Range South-l, 711.0-712.0 m, Carnarvon Basin.
Occurrence. Rare to common in the Samlandia carnarvonensis Zone to the Cladopyxidium foveolatum Subzone (late Campanian to early Maastrichtian) of the Carnarvon, Canning, Browse and Bonaparte Basins.
Holotype: McMinn, 1988, figs.7A-C; Fensome et al., 1996, figs.1-3 - p.2081.
Age: Late Campanian-Early Maastrichtian.
Original description (McMinn, 1988)
Description. Proximate, subspherical to ellipsoidal cyst. The wall is composed of three layers; an endophragm, a periphragm and an ectophragm. The endophragm is 2-3 µm thick and smooth to finely granulate. The periphragm is 0.5 µm thick and developed into a reticulum with cell widths up to 8 µm and
a height up to 2 µm. Lumina are ovaI to polygonal. The endophragm and periphragm are closely appressed while the ectophragm is supported by the walls of the reticulum. A short apical horn, formed by an extension of the periphragm and ectophragm, is usually present. The archeopyle is precingular, type P (3" only), and the operculum is normally free. There is no indication of a parasulcus or a paracingulum.
Size. Pericyst (excluding reticulum); length 64(61)54 µm, width 61(54)50 µm. Twenty specimens were measured.
Comparison. Samlandia carnarvonensis resembles the Late Eocene species Samlandia reticulifera Cookson & Eisenack 1965. It is distinguished by its lower, finer reticulum and the absence of distinctly higher ornament around the equator and at the antapex. The presence of a reticulum aIso distinguishes Samlandia carnarvonensis from the other Late Cretaceous species Samlandia mayi sp. nov. and Samlandia vermicutaria sp. nov. S. carnarvonensis is similar to Deflandrea extrema Cookson & Eisenack 1974, but the description and illustration of the type of the latter do not allow a closer comparison. The type locality of Deflandrea extrema, however, is from a Turonian sequence in Balcatta-1 bore, whereas Samlandia carnarvonensis has a late Campanian to early Maastrichtian range. The two species, therefore, apparently
have distinct and separate stratigraphic ranges.
Type material. Holotype, Fig. 7A-C; F47024, Wapet Rough Range South-l, 711.0-712.0 m, Carnarvon Basin.
Occurrence. Rare to common in the Samlandia carnarvonensis Zone to the Cladopyxidium foveolatum Subzone (late Campanian to early Maastrichtian) of the Carnarvon, Canning, Browse and Bonaparte Basins.