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Pyxidinopsis epakros
Pyxidinopsis epakros Willumsen, 2011, p.226,228, figs.12G–J.
Holotype: Willumsen, 2011, fig.12H. N.I.A.
Age: late Maastrichtian–earliest Paleocene.
Original description (Willumsen, 2011)
Types. Holotype, Mead Stream, P30/f906, L18315/3, 6 μm, EF: L28,4 (Fig. 12H). Paratype, Branch Stream, O30/f354, L19341/1, 16 μm, EF: M40,1 (Fig. 12G). Type unit and locality. Mead Hill Formation, Mead Stream section, Clarence Valley, Marlborough.
Etymology. Epakros (Greek)=point at the end, which refers to the spines developed on the reticulate ornament of this cyst.
Diagnosis. Relatively small, subspherical, Pyxidiniopsis with a finely reticulate autophragm. Reticulum is irregular and muri are covered by evenly dispersed spines. Tabulation not indicated except for a precingular archeopyle of type P (3″).
Description. Acavate, proximate, small subspherical gonyaulacoid dinocyst with a low irregular reticulate surface ornamentation. The cyst wall is ca 1–2 μm thick. Lumina have a diameter <2 μm and they vary in size and shape in a single specimen. The muri are covered evenly by spines with a height of about 2–3 μm (Fig. 12I, J). Paratabulation is indicated only by a precingular archeopyle formed by the loss of paraplate 3″. Operculum has an isodeltaform camerate outline and it is commonly attached to the archeopyle margin along the contact between cingular plates or paraplate 2″ or 4″. Total diameter 45(48)50 μm [4 specimens measured].
Remarks. Pyxidinopsis epakros differs from P. meadensis by being half the size and in having a less robust and complete reticulate surface ornamentation covered by relatively elongate spines. The development of spines on the incomplete reticulum also differentiates P. epakrosis from Pyxidinopsis everriculum and P. ardonensis (Jan du Chêne 1988).
Age and distribution. The FO of P. epakros was not observed, but its LO is recorded in the earliest Paleocene radiolarian zone RP2. Pyxidinopsis epakros is most common in lowermost Paleocene strata from the Marlborough region and was recorded in sections at Branch Stream, Chancet Rocks, Grey River, Mead Stream, mid-Waipara River, Wharanui Point and Woodside Creek.
Holotype: Willumsen, 2011, fig.12H. N.I.A.
Age: late Maastrichtian–earliest Paleocene.
Original description (Willumsen, 2011)
Types. Holotype, Mead Stream, P30/f906, L18315/3, 6 μm, EF: L28,4 (Fig. 12H). Paratype, Branch Stream, O30/f354, L19341/1, 16 μm, EF: M40,1 (Fig. 12G). Type unit and locality. Mead Hill Formation, Mead Stream section, Clarence Valley, Marlborough.
Etymology. Epakros (Greek)=point at the end, which refers to the spines developed on the reticulate ornament of this cyst.
Diagnosis. Relatively small, subspherical, Pyxidiniopsis with a finely reticulate autophragm. Reticulum is irregular and muri are covered by evenly dispersed spines. Tabulation not indicated except for a precingular archeopyle of type P (3″).
Description. Acavate, proximate, small subspherical gonyaulacoid dinocyst with a low irregular reticulate surface ornamentation. The cyst wall is ca 1–2 μm thick. Lumina have a diameter <2 μm and they vary in size and shape in a single specimen. The muri are covered evenly by spines with a height of about 2–3 μm (Fig. 12I, J). Paratabulation is indicated only by a precingular archeopyle formed by the loss of paraplate 3″. Operculum has an isodeltaform camerate outline and it is commonly attached to the archeopyle margin along the contact between cingular plates or paraplate 2″ or 4″. Total diameter 45(48)50 μm [4 specimens measured].
Remarks. Pyxidinopsis epakros differs from P. meadensis by being half the size and in having a less robust and complete reticulate surface ornamentation covered by relatively elongate spines. The development of spines on the incomplete reticulum also differentiates P. epakrosis from Pyxidinopsis everriculum and P. ardonensis (Jan du Chêne 1988).
Age and distribution. The FO of P. epakros was not observed, but its LO is recorded in the earliest Paleocene radiolarian zone RP2. Pyxidinopsis epakros is most common in lowermost Paleocene strata from the Marlborough region and was recorded in sections at Branch Stream, Chancet Rocks, Grey River, Mead Stream, mid-Waipara River, Wharanui Point and Woodside Creek.