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Stichodinium parisiense
Stichodinium parisiense Iakovleva, 2016, p.18 (on PDF initially published online), pl.3, figs.1–2,4–5,7–8,10–11; text-fig.4b (part). Holotype: Iakovleva, 2016, pl.3, figs.1–2. Age: earliest Eocene.
Original description (Iakovleva, 2016)
Diagnosis. A species of Stichodinium with rounded-pentagonal outline and parasutural ornamentation expressed by low crests with well developed adnate processes.
Description. A mid-size circumcavate cyst with rounded-pentagonal outline. An apical horn is not developed or is very short. Lateral horns are reduced or slightly extended. Antapical horns vary from being short and of the same length to longer, with the right horn being more pronounced. Periphragm thin; sutures ornamented with processes that may be isolated or united proximally. Endocyst is subcircular; endophragm is thin and smooth. Archaeopyle latiepeliform, operculum free or partially attached.
Dimensions.
Holotype: pericyst length 79 µm; pericyst width 81 µm; endocyst length 65 µm; endocyst width 65. Paratype 1: pericyst length 80 µm; pericyst width 81 µm; endocyst length 60 µm; endocyst width 61 µm. Dimensions of measured specimens: pericyst length 68–101 µm (mean value 85 µm); pericyst width 69–100 µm (mean value 82 µm); endocyst length 49–74 µm (mean value 62 µm); endocyst width 52–68 µm (mean value 63 µm). Ten specimens measured.
Comparison. Stichodinium parisiense differs from other species of the genus in having a rounded-pentagonal pericyst and in the intraspecific variation in the development of lateral and antapical horns. S. parisiense differs from S. galliciense by its rounded outline and the absence of the outline ornamentation by distinctive outgrowths. It also differs from S. sympagicum by more clearly pronounced horns (paratype 2). S. parisiense differs from S. elegantulum and S. prostimus by the character of sutural ornamentation expressed by processes on the low crests.
Stratigraphical range. Earliest Eocene.
Derivation of name. From the Paris Basin, where the holotype was recovered.
Original description (Iakovleva, 2016)
Diagnosis. A species of Stichodinium with rounded-pentagonal outline and parasutural ornamentation expressed by low crests with well developed adnate processes.
Description. A mid-size circumcavate cyst with rounded-pentagonal outline. An apical horn is not developed or is very short. Lateral horns are reduced or slightly extended. Antapical horns vary from being short and of the same length to longer, with the right horn being more pronounced. Periphragm thin; sutures ornamented with processes that may be isolated or united proximally. Endocyst is subcircular; endophragm is thin and smooth. Archaeopyle latiepeliform, operculum free or partially attached.
Dimensions.
Holotype: pericyst length 79 µm; pericyst width 81 µm; endocyst length 65 µm; endocyst width 65. Paratype 1: pericyst length 80 µm; pericyst width 81 µm; endocyst length 60 µm; endocyst width 61 µm. Dimensions of measured specimens: pericyst length 68–101 µm (mean value 85 µm); pericyst width 69–100 µm (mean value 82 µm); endocyst length 49–74 µm (mean value 62 µm); endocyst width 52–68 µm (mean value 63 µm). Ten specimens measured.
Comparison. Stichodinium parisiense differs from other species of the genus in having a rounded-pentagonal pericyst and in the intraspecific variation in the development of lateral and antapical horns. S. parisiense differs from S. galliciense by its rounded outline and the absence of the outline ornamentation by distinctive outgrowths. It also differs from S. sympagicum by more clearly pronounced horns (paratype 2). S. parisiense differs from S. elegantulum and S. prostimus by the character of sutural ornamentation expressed by processes on the low crests.
Stratigraphical range. Earliest Eocene.
Derivation of name. From the Paris Basin, where the holotype was recovered.