Back
Membranophoridium perforatum
Membranophoridium perforatum Wilson 1988, p.26
This name was not validly published in Wilson (1985, p.93) since no description or illustration was provided.
Holotype: Wilson, 1988, pl.16, figs.5a–b; Fensome et al., 1996, figs.1–2 — p.2271.
Locus typicus: Waipawa Section, Hawkes Bay, New Zealand
Stratum typicum: Early Eocene (Mangaorapan- Heretaungan)
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Membranophoridium perforatum Wilson, 1988, has a well developed ambital pericoel and a perforate periphragm, with the perforations, which tend to be concentrated on the periphery, being up to 10 µm in diameter. Occasionally, solid slender processes connect the pericyst to the endocyst in the antapical region. Membranophoridium perforatum differs from M. aspinatum mainly in having a partially perforate periphragm and in occasionally having a few processes linking the periphragm and endophragm. In addition, the apical and antapical lobations, well-developed in the type species, are poorly developed or absent in M. perforatum. Membranophoridium perforatum has some resemblance to Senoniasphaera inornata but differs in lacking true polar lobations and in having a partially perforate periphragm. The size of M. perforatum is 61-80 µm diameter.
--------------------------------------------------
Original description: Wilson 1988
Cyst lenticular, subspherical, bilayered, circumcavate, periphragm and endophragm in closest contact only in mid dorsal and mid ventral regions. Periphragm thin, generally folded, outline somewhat irregular to undulating, smooth with a sub-pointed apex and occasionally two poorly developed antapical lobations present. Perforations (diameter up to 10 µm) present in variable numbers, mainly around periphragm margin. Occasional solid slender processes (breadth up to 4 Ám) sometimes connect periphragm to endophragm in antapical area. Endocyst thin walled, smooth, with a circular outline. Paratabulation indication by archeopyle only, formula unknown. Archeopyle relatively broad, apical, type tA; principal archeopyle suture zig-zag, parasulcal notch indicating apical position of parasulcus. No indication of paracingulum.
Dimensions: Holotype (complete specimen) overall length 97 µm, breadth 61 µm. Maximum thickness of pericoel 17 µm. Range: overall diameter 61 (72) 80 µm, diameter of endocyst 49 (58) 61 µm (n = 10).
Affinities:
Wilson, 1988, p. 26: Membranophoridium perforatum differs from the type species mainly in having a partially perforate periphragm and in occasionally having a few processes linking the periphragm and endophragm. In addition, the apical and antapical lobations, well-developed in the type species, are poorly developed or absent in M. perforatum. The species has some resemblance to Senoniasphaera inornata (Drugg) but differs in lacking true polar lobations and in having a partially perforate periphragm.
This name was not validly published in Wilson (1985, p.93) since no description or illustration was provided.
Holotype: Wilson, 1988, pl.16, figs.5a–b; Fensome et al., 1996, figs.1–2 — p.2271.
Locus typicus: Waipawa Section, Hawkes Bay, New Zealand
Stratum typicum: Early Eocene (Mangaorapan- Heretaungan)
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Membranophoridium perforatum Wilson, 1988, has a well developed ambital pericoel and a perforate periphragm, with the perforations, which tend to be concentrated on the periphery, being up to 10 µm in diameter. Occasionally, solid slender processes connect the pericyst to the endocyst in the antapical region. Membranophoridium perforatum differs from M. aspinatum mainly in having a partially perforate periphragm and in occasionally having a few processes linking the periphragm and endophragm. In addition, the apical and antapical lobations, well-developed in the type species, are poorly developed or absent in M. perforatum. Membranophoridium perforatum has some resemblance to Senoniasphaera inornata but differs in lacking true polar lobations and in having a partially perforate periphragm. The size of M. perforatum is 61-80 µm diameter.
--------------------------------------------------
Original description: Wilson 1988
Cyst lenticular, subspherical, bilayered, circumcavate, periphragm and endophragm in closest contact only in mid dorsal and mid ventral regions. Periphragm thin, generally folded, outline somewhat irregular to undulating, smooth with a sub-pointed apex and occasionally two poorly developed antapical lobations present. Perforations (diameter up to 10 µm) present in variable numbers, mainly around periphragm margin. Occasional solid slender processes (breadth up to 4 Ám) sometimes connect periphragm to endophragm in antapical area. Endocyst thin walled, smooth, with a circular outline. Paratabulation indication by archeopyle only, formula unknown. Archeopyle relatively broad, apical, type tA; principal archeopyle suture zig-zag, parasulcal notch indicating apical position of parasulcus. No indication of paracingulum.
Dimensions: Holotype (complete specimen) overall length 97 µm, breadth 61 µm. Maximum thickness of pericoel 17 µm. Range: overall diameter 61 (72) 80 µm, diameter of endocyst 49 (58) 61 µm (n = 10).
Affinities:
Wilson, 1988, p. 26: Membranophoridium perforatum differs from the type species mainly in having a partially perforate periphragm and in occasionally having a few processes linking the periphragm and endophragm. In addition, the apical and antapical lobations, well-developed in the type species, are poorly developed or absent in M. perforatum. The species has some resemblance to Senoniasphaera inornata (Drugg) but differs in lacking true polar lobations and in having a partially perforate periphragm.