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Pyxidinopsis reticulata
Pyxidinopsis reticulata McMinn and Sun Xuekun, 1994, p.48,50, pl.3, figs.1–4. Emendation: Marret and de Vernal, 1997, p.387.
Junior homonym: Pyxidinopsis reticulata (Jiabo 1978) Pan Zhaoren in Xu Jinli et al.
Holotype: McMinn and Sun Xuekun, 1994, pl.3, figs.3–4.
Age: Holocene.
Original description (McMinn and Sun Xuekun, 1994)
Derivation of name. Named after the reticulate surface ornamentation.
Holotype. Plate 3, figs. 3, 4; Holocene; surface sample J1043KER, Chatham Rise, east of New Zealand.
Diagnosis. Small, subspherical cyst comprised of autophragm only. Wall surface is microgranulate-reticulate. Archeopyle is precingular, Type P (3"only), and the operculum is free.
Discription: Small, subspherical cyst comprised of autophragm only. The autophragms is <1µm thick. Wall surface is finely wrinkled with a low, irregular reticulum composed of cells with a diameter of <3µm. Surface is also very finely granulate. Paratabulation is indicated by an archeopyle only, which is precingular, Type P (3"only); the operculum is detached. The paracingulum and parasulcus are not indicated.
Comments: Pyxidinopsis reticulata sp. nov. differs from other species of Pyxidinopsis in its small size, thin wall and microgranulate-reticulate wall surface. In the early stages of this study specimens of this taxon were thought to belong to Tectatodinium pellitum, however, it became clear that forms with a simple, non-tectate wall structure could not be accomodated within Tectatodinium. The only genera comprised of subspherical cysts with a single wall layer, a precingular (1P) archeopyle and without processes is Pyxidinopsis.
Dimensions: Diameter 28(31)35 µm, wall thickness 1 µm; ten specimens measured.
Occurrence: This taxa is rare to the north of the STC (0,3%) but comprises an averages of 4.2% to the south. It was recorded as Pyxidiopsis sp. by Sun and McMinn (1994). It has also been found in surface and Quatenary samples from the Gippsland Basin and western Tasmania (McMinn, unpubl. data).
Junior homonym: Pyxidinopsis reticulata (Jiabo 1978) Pan Zhaoren in Xu Jinli et al.
Holotype: McMinn and Sun Xuekun, 1994, pl.3, figs.3–4.
Age: Holocene.
Original description (McMinn and Sun Xuekun, 1994)
Derivation of name. Named after the reticulate surface ornamentation.
Holotype. Plate 3, figs. 3, 4; Holocene; surface sample J1043KER, Chatham Rise, east of New Zealand.
Diagnosis. Small, subspherical cyst comprised of autophragm only. Wall surface is microgranulate-reticulate. Archeopyle is precingular, Type P (3"only), and the operculum is free.
Discription: Small, subspherical cyst comprised of autophragm only. The autophragms is <1µm thick. Wall surface is finely wrinkled with a low, irregular reticulum composed of cells with a diameter of <3µm. Surface is also very finely granulate. Paratabulation is indicated by an archeopyle only, which is precingular, Type P (3"only); the operculum is detached. The paracingulum and parasulcus are not indicated.
Comments: Pyxidinopsis reticulata sp. nov. differs from other species of Pyxidinopsis in its small size, thin wall and microgranulate-reticulate wall surface. In the early stages of this study specimens of this taxon were thought to belong to Tectatodinium pellitum, however, it became clear that forms with a simple, non-tectate wall structure could not be accomodated within Tectatodinium. The only genera comprised of subspherical cysts with a single wall layer, a precingular (1P) archeopyle and without processes is Pyxidinopsis.
Dimensions: Diameter 28(31)35 µm, wall thickness 1 µm; ten specimens measured.
Occurrence: This taxa is rare to the north of the STC (0,3%) but comprises an averages of 4.2% to the south. It was recorded as Pyxidiopsis sp. by Sun and McMinn (1994). It has also been found in surface and Quatenary samples from the Gippsland Basin and western Tasmania (McMinn, unpubl. data).