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Riculacysta perforata
Riculacysta perforata Stover, 1977, p.77-78
Taxonomic junior synonym: Cyclonephelium semitectum, according to Köthe (1990, p.50) — however, Kirsch (1991, p.129) retained Cyclonephelium (as Riculacysta, now Glaphyrocysta) semitectum.
Holotype: Stover, 1977, pl.2, figs.22-24
Locus typicus: Corehole 5/5B, Blake PLateau, Western N Atlantic
Stratum typicum: Middle Oligocene
Original description: Stover, 1977, p. 77-78
Cysts are chorate with a generally subspherical body that may have unequally developed antapical lobes separated by a medial concavity. Autophragm is punctoreticulate and forms solid, typically slender, distally branched processes on the ventrolateral and lateral surfaces. Processes are mostly isolated, although a few adjacent processes arise from low, short proximal ridges; some processes appear to be intratabular whereas others may be penitabular. Processes characteristically longest adjacent to midventral area. Distal ends of processes connected by thin, discontinuous, irregularly perforate to trabecular ectophragm that is close to or appressed to the autophragm in the middorsal area and usually forms a curtain-like feature above the dorsal antapical area.
Archeopyle is apical, type A, principal suture slightly angular and without a prominent parasulcal notch; operculum is free and the ventral processes are longer than the dorsal processes. Paratabulation indicated by archeopyle, by paracingulum on the dorsal surface only and less distinctly by positions of some processes; paratabulation generally expressed more clearly on the epicyst than on the hypocyst and processes are typically lacking on paraplate 6"". Preclngular paraplates delimited apically by principal archeopyle suture and laterally by short accessory sutures. Paracingulum expressed dorsally by two low, parallel, transverse ridges and laterally by processes. Parasulcus not differentiated per se; it lies within unornamented midventral area posterior to parasulcal notch.
Diameter at paracingulum 104 to 135 µm; autocyst without processes 68 to 80 µm; processes from a few to 32 µm in length.
Comment: Stover, 1977, p. 78
The undescribed specimen illustrated by Williams and Brideaux (1975, pl. 29, fig. 1) and identified as Cyclonephelium sp. C may be an example of Riculacysta perforata.
Taxonomic junior synonym: Cyclonephelium semitectum, according to Köthe (1990, p.50) — however, Kirsch (1991, p.129) retained Cyclonephelium (as Riculacysta, now Glaphyrocysta) semitectum.
Holotype: Stover, 1977, pl.2, figs.22-24
Locus typicus: Corehole 5/5B, Blake PLateau, Western N Atlantic
Stratum typicum: Middle Oligocene
Original description: Stover, 1977, p. 77-78
Cysts are chorate with a generally subspherical body that may have unequally developed antapical lobes separated by a medial concavity. Autophragm is punctoreticulate and forms solid, typically slender, distally branched processes on the ventrolateral and lateral surfaces. Processes are mostly isolated, although a few adjacent processes arise from low, short proximal ridges; some processes appear to be intratabular whereas others may be penitabular. Processes characteristically longest adjacent to midventral area. Distal ends of processes connected by thin, discontinuous, irregularly perforate to trabecular ectophragm that is close to or appressed to the autophragm in the middorsal area and usually forms a curtain-like feature above the dorsal antapical area.
Archeopyle is apical, type A, principal suture slightly angular and without a prominent parasulcal notch; operculum is free and the ventral processes are longer than the dorsal processes. Paratabulation indicated by archeopyle, by paracingulum on the dorsal surface only and less distinctly by positions of some processes; paratabulation generally expressed more clearly on the epicyst than on the hypocyst and processes are typically lacking on paraplate 6"". Preclngular paraplates delimited apically by principal archeopyle suture and laterally by short accessory sutures. Paracingulum expressed dorsally by two low, parallel, transverse ridges and laterally by processes. Parasulcus not differentiated per se; it lies within unornamented midventral area posterior to parasulcal notch.
Diameter at paracingulum 104 to 135 µm; autocyst without processes 68 to 80 µm; processes from a few to 32 µm in length.
Comment: Stover, 1977, p. 78
The undescribed specimen illustrated by Williams and Brideaux (1975, pl. 29, fig. 1) and identified as Cyclonephelium sp. C may be an example of Riculacysta perforata.