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Castellodinium compactum
Castellodinium compactum, (Michoux, 1988, p.38–39, pl.9, figs.1–9; pl.10, figs.1–9 (not fig.10); text-figs.13A–B,14), Williams et al., 2015, p.301.
Holotype: Michoux, 1988, pl.9, figs.1–3; text-figs.13A–B.
Age: middle Eocene.
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Original description: Michoux, 1988, p. 38-39
Diagnosis:
Circumcavate peridinioid cyst, pentagonal to subcircular in outline, with moderate dorso-ventral compression.
Paratabulation outlined by short, blunt, parasutural processes, sometimes supported by a proximal membrane.
Archeopyle rounded-rectangular. Opercula free, often adherent.
Description:
Cyst shape is highly variable, due to differential horn development, ranging from pentagonal to rhomboidal to subcircular.
The endophragm is subcircular to rhomboidal. The cyst is typically circumcavate, although in some cases the periphragm and endophragm may come in contact over a limited portion of the perimeter. The periphragm is smooth, and the endophragm slightly granular.
Relatively short (up to 6 llm in length), blunt processes are aligned along the parasutures, isolated or arising from a proximal membrane.
The complete sulcal paratabulation is expressed. Anterior sulcal (as) paraplate is quadrangular, overlying two adjacent, elongated, oblique paraplates separated by a row of free standing processes. The posterior sulcal (ps) paraplate occupies the entire posterior part of the ventral hypocyst.
The archeopyle is rectangular with rounded corners. The periarcheopyle is slightly higher than the endoarcheopyle. Although the archeopyle suture is developed around the entire perimeter of paraplate 2a, the opercula generally remain adherent.
Paratabulation formula: 4", 3a, 7", Xc, 5""", 2"""", 4s.
Dimensions:
Pericyst: Length: 90 (99) 108 µm. Width: 90 (94) 99 µm. Holotype: 99 x 90 µm. Archeopyle. Length: 21 (22.8) 23 µm. Width: 18 (21.6) 22 µm. Holotype: 22 x 22 µm.
Affinities:
Wilsonidium compactum is comparable to Wilsonidium echinosuturatum (Wilson) Lentin & Williams in possessing parasutural membranes supporting the processes. W. echinosuturatum, however, is much larger (up to 160 µm in length, according to Wilson, 1967, p. 479), with larger horns, and bears more prominent parasutural crests and longer processes (up to 16 µm in length) that are oblate or capitate rather than blunt.
Holotype: Michoux, 1988, pl.9, figs.1–3; text-figs.13A–B.
Age: middle Eocene.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: Michoux, 1988, p. 38-39
Diagnosis:
Circumcavate peridinioid cyst, pentagonal to subcircular in outline, with moderate dorso-ventral compression.
Paratabulation outlined by short, blunt, parasutural processes, sometimes supported by a proximal membrane.
Archeopyle rounded-rectangular. Opercula free, often adherent.
Description:
Cyst shape is highly variable, due to differential horn development, ranging from pentagonal to rhomboidal to subcircular.
The endophragm is subcircular to rhomboidal. The cyst is typically circumcavate, although in some cases the periphragm and endophragm may come in contact over a limited portion of the perimeter. The periphragm is smooth, and the endophragm slightly granular.
Relatively short (up to 6 llm in length), blunt processes are aligned along the parasutures, isolated or arising from a proximal membrane.
The complete sulcal paratabulation is expressed. Anterior sulcal (as) paraplate is quadrangular, overlying two adjacent, elongated, oblique paraplates separated by a row of free standing processes. The posterior sulcal (ps) paraplate occupies the entire posterior part of the ventral hypocyst.
The archeopyle is rectangular with rounded corners. The periarcheopyle is slightly higher than the endoarcheopyle. Although the archeopyle suture is developed around the entire perimeter of paraplate 2a, the opercula generally remain adherent.
Paratabulation formula: 4", 3a, 7", Xc, 5""", 2"""", 4s.
Dimensions:
Pericyst: Length: 90 (99) 108 µm. Width: 90 (94) 99 µm. Holotype: 99 x 90 µm. Archeopyle. Length: 21 (22.8) 23 µm. Width: 18 (21.6) 22 µm. Holotype: 22 x 22 µm.
Affinities:
Wilsonidium compactum is comparable to Wilsonidium echinosuturatum (Wilson) Lentin & Williams in possessing parasutural membranes supporting the processes. W. echinosuturatum, however, is much larger (up to 160 µm in length, according to Wilson, 1967, p. 479), with larger horns, and bears more prominent parasutural crests and longer processes (up to 16 µm in length) that are oblate or capitate rather than blunt.