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Hystrichokolpoma incertum
From Fensome et al., 2019:
Hystrichokolpoma incertum Michoux, 1985, p.143–144, pl.2, figs.5–7,9,12,13–15; pl.3, figs.11–12; text-figs.3A–B. Holotype: Michoux, 1985, pl.2, figs.5–7; text-figs.3A–B; Fauconnier and Masure, 2004, pl.42, figs.13–15. Questionable assignment: Michoux (1985, p.143). Age: Early to Middle Eocene.
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Original description: [Michoux, 1985] (translated from French):
Hystrichokolpoma ? incerta n. sp.
(Pl. 2, figs. 5-7, 9, 12, 13-15; Pl. 3, fig. 11-12; text-fig. 3)
Holotype: Slide L6-6, coordinates S35.
Origin of the name: Referring to the uncertain assignment of this species to the genus Hystrichokolpoma.
Type locality: Section from the Louer Bridge, marl-limestone from the base of the Nousse Beds.
Diagnosis: Chorate cyst with a spherical central body, combining characteristics of the genus Hystrichokolpoma (large antapical processes, tabular precingulate processes) with specific features (non-tabular cingulate and postcingulate processes).
Description: Chorate cyst with a spherical central body. The periphragm forms hollow, striated, distally closed processes. It displays a relatively dense granule ornamentation between the processes, clearly visible on SEM (PI. 2, Fig. 12).
The precingulate processes are intratabular, one per paraplate. The 1" to 5" processes have a quadrangular base. Some are cubic, others have the shape of a truncated pyramid. Their distal end is closed, often notched, and decorated with tubules. The 6" process and the anterior sulcal process (as) are smaller.
The postcingulate processes are non-tabular. Some are similar in shape to the precingulate processes, but smaller. Most are identical to the cingulate and sulcal processes, which have the shape of rounded cones, more or less elongated, sometimes slightly arched.
The antapical process is a flattened sac, subcircular (Plate 2, Fig. 5-6) to subrectangular (Plate 3, Fig. 11-12) in section. It has a distal opening.
The archaeopyle is apical. The operculum is free. It has never been observed in preparations.
Dimensions: Height of central body: 30 (34) 42 μm; width of central body: 33 (35) 40 μm; length of processes Precingulates: up to 13 μm; antapical process length: up to 28 μm; 8 specimens measured.
Discussion: We assigned this species to the genus Hystrichokolpoma because of the presence of intratabular precingulate processes, larger than the cingulate and sulcal processes, and a large antapical process. However, it shares affinities with the genus Diphyes, which also has a large antapical process and non-tabular processes on the rest of the cyst, whereas in H. incerta, the precingulate area bears intratabular processes.
Hystrichokolpoma incertum Michoux, 1985, p.143–144, pl.2, figs.5–7,9,12,13–15; pl.3, figs.11–12; text-figs.3A–B. Holotype: Michoux, 1985, pl.2, figs.5–7; text-figs.3A–B; Fauconnier and Masure, 2004, pl.42, figs.13–15. Questionable assignment: Michoux (1985, p.143). Age: Early to Middle Eocene.
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Original description: [Michoux, 1985] (translated from French):
Hystrichokolpoma ? incerta n. sp.
(Pl. 2, figs. 5-7, 9, 12, 13-15; Pl. 3, fig. 11-12; text-fig. 3)
Holotype: Slide L6-6, coordinates S35.
Origin of the name: Referring to the uncertain assignment of this species to the genus Hystrichokolpoma.
Type locality: Section from the Louer Bridge, marl-limestone from the base of the Nousse Beds.
Diagnosis: Chorate cyst with a spherical central body, combining characteristics of the genus Hystrichokolpoma (large antapical processes, tabular precingulate processes) with specific features (non-tabular cingulate and postcingulate processes).
Description: Chorate cyst with a spherical central body. The periphragm forms hollow, striated, distally closed processes. It displays a relatively dense granule ornamentation between the processes, clearly visible on SEM (PI. 2, Fig. 12).
The precingulate processes are intratabular, one per paraplate. The 1" to 5" processes have a quadrangular base. Some are cubic, others have the shape of a truncated pyramid. Their distal end is closed, often notched, and decorated with tubules. The 6" process and the anterior sulcal process (as) are smaller.
The postcingulate processes are non-tabular. Some are similar in shape to the precingulate processes, but smaller. Most are identical to the cingulate and sulcal processes, which have the shape of rounded cones, more or less elongated, sometimes slightly arched.
The antapical process is a flattened sac, subcircular (Plate 2, Fig. 5-6) to subrectangular (Plate 3, Fig. 11-12) in section. It has a distal opening.
The archaeopyle is apical. The operculum is free. It has never been observed in preparations.
Dimensions: Height of central body: 30 (34) 42 μm; width of central body: 33 (35) 40 μm; length of processes Precingulates: up to 13 μm; antapical process length: up to 28 μm; 8 specimens measured.
Discussion: We assigned this species to the genus Hystrichokolpoma because of the presence of intratabular precingulate processes, larger than the cingulate and sulcal processes, and a large antapical process. However, it shares affinities with the genus Diphyes, which also has a large antapical process and non-tabular processes on the rest of the cyst, whereas in H. incerta, the precingulate area bears intratabular processes.