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Dingodinium subtile
Dingodinium subtile Pestchevitskaya, 2006, p.S644–645, pl.7, figs.2,6–8,10–11; text-fig.3E.
Holotype: Pestchevitskaya, 2006, pl.7, fig.2.
Age: Berriasian–early Valanginian.
Original description (Pestchevitskaya, 2006):
Dingodinium subtile Pestchevitskaya, sp. nov. Plate 7, figs. 2, 6–8, 10, and 11
Etymology. From the Latin subtile (thin) characterizing the cyst wall morphology.
Holotype. Novosibirsk, IPGG, no. 124.1/10; north of Middle Siberia, Paksa Peninsula, outcrop 33, layer 49, Berriasian, Tollia tolli Zone; Pl. 7, fig. 2.
Paratype. Novosibirsk, IPGG, no. 131.1/6, pl. 1, figs. 6, 10, 11; north-central Siberia, Paksa Peninsula, outcrop 33, layer 42, Berriasian, Tollia tolli Zone.
Diagnosis. Cyst proximate and camocavate; endocyst ovoid or pear-shaped with rather thin granular endophragm; pericyst smooth and spherical or ellipsoidal, apex and antapex rounded; paratabulation gonyaulacoid, when apparent expressed on endocyst and pericyst by fine paratabulation features and archeopyle; formula 4', ?3a, 7'', 7c, 5s, 6''', 1p, 1''''; archeopyle apical, combination, or intercalary.
Description (Fig. 3E). The cyst is proximate and camocavate. The endocyst is ovate or pear-shaped with a relatively thin endophragm, which is sculptured with numerous small granules. The pericyst is rounded or broadly oval; the apex and antapex are rounded. The periphragm is laevigate, thin, transparent, is folded in thin folds, which occasionally make an impression of indistinct striation. Usually, the pericoel is prominent, except for the dorsal side, where the layers of the wall are often appressed to each other. Occasionally, it becomes narrower near the cingulum. The maximal width is observed in the apical area. The paratabulation is not always visible. It is indicated on the endocyst and pericyst by fine parasutural features and archeopyle. The formula is 4', ?3a, 7'', 7c, 5s, 6''', 1p, 1''''. The paracingulum and sulcus are indicated by more distinct parasutural features. The archeopyle structure is unclear: apical, combination, and intercalary.
Measurements (µm): the length of the pericyst is 45–57; the length of the endocyst is 40–46; the width of the pericyst is 39–46; the width of the endocyst is 34–46 in the cingular area and 12–28 in the apical area; and the width of the pericoel is 2–5 in the cingular area (ventral and lateral sides), 7–9 in the antapical area, 8−14 in the apical area, and 0–2 on the dorsal side.
Variability. The size of the cyst and the width of the pericoel in different regions are variable as well as the outline of the endocyst (from ovate to pear-shaped).
Comparison. The absence of the apical horn on the pericyst makes D. subtile closer to D. jurassicum Cookson et Eisenack, which differs in the rounded endocyst sculptured with short spines (Cookson and Eisenack, 1958). By the morphology of the endophragm, D. subtile resembles D. minutum Dodekova (Dodekova, 1975) and D. tuberosum (Gitmez) Fisher et Riley (Gitmez, 1970), but these two species are characterized by a rounded or oval endocyst and the presence of apical horn on the pericyst.
Locality. Khatanga Depression, Nordvik Peninsula, outcrop 33, layers 37–56, Berriasian–Lower Valanginian, Bojarkia meseznikovi ammonite Zone–lower part of Neotollia klimovskiensis ammonite Zone; Ust’- Yenisei Region, borehole Severo-Vologochanskaya 18, 984.3–977.0 m, upper Berriasian–lower Lower Valanginian.
Material. More than 20 specimens of good or adequate preservation.
Holotype: Pestchevitskaya, 2006, pl.7, fig.2.
Age: Berriasian–early Valanginian.
Original description (Pestchevitskaya, 2006):
Dingodinium subtile Pestchevitskaya, sp. nov. Plate 7, figs. 2, 6–8, 10, and 11
Etymology. From the Latin subtile (thin) characterizing the cyst wall morphology.
Holotype. Novosibirsk, IPGG, no. 124.1/10; north of Middle Siberia, Paksa Peninsula, outcrop 33, layer 49, Berriasian, Tollia tolli Zone; Pl. 7, fig. 2.
Paratype. Novosibirsk, IPGG, no. 131.1/6, pl. 1, figs. 6, 10, 11; north-central Siberia, Paksa Peninsula, outcrop 33, layer 42, Berriasian, Tollia tolli Zone.
Diagnosis. Cyst proximate and camocavate; endocyst ovoid or pear-shaped with rather thin granular endophragm; pericyst smooth and spherical or ellipsoidal, apex and antapex rounded; paratabulation gonyaulacoid, when apparent expressed on endocyst and pericyst by fine paratabulation features and archeopyle; formula 4', ?3a, 7'', 7c, 5s, 6''', 1p, 1''''; archeopyle apical, combination, or intercalary.
Description (Fig. 3E). The cyst is proximate and camocavate. The endocyst is ovate or pear-shaped with a relatively thin endophragm, which is sculptured with numerous small granules. The pericyst is rounded or broadly oval; the apex and antapex are rounded. The periphragm is laevigate, thin, transparent, is folded in thin folds, which occasionally make an impression of indistinct striation. Usually, the pericoel is prominent, except for the dorsal side, where the layers of the wall are often appressed to each other. Occasionally, it becomes narrower near the cingulum. The maximal width is observed in the apical area. The paratabulation is not always visible. It is indicated on the endocyst and pericyst by fine parasutural features and archeopyle. The formula is 4', ?3a, 7'', 7c, 5s, 6''', 1p, 1''''. The paracingulum and sulcus are indicated by more distinct parasutural features. The archeopyle structure is unclear: apical, combination, and intercalary.
Measurements (µm): the length of the pericyst is 45–57; the length of the endocyst is 40–46; the width of the pericyst is 39–46; the width of the endocyst is 34–46 in the cingular area and 12–28 in the apical area; and the width of the pericoel is 2–5 in the cingular area (ventral and lateral sides), 7–9 in the antapical area, 8−14 in the apical area, and 0–2 on the dorsal side.
Variability. The size of the cyst and the width of the pericoel in different regions are variable as well as the outline of the endocyst (from ovate to pear-shaped).
Comparison. The absence of the apical horn on the pericyst makes D. subtile closer to D. jurassicum Cookson et Eisenack, which differs in the rounded endocyst sculptured with short spines (Cookson and Eisenack, 1958). By the morphology of the endophragm, D. subtile resembles D. minutum Dodekova (Dodekova, 1975) and D. tuberosum (Gitmez) Fisher et Riley (Gitmez, 1970), but these two species are characterized by a rounded or oval endocyst and the presence of apical horn on the pericyst.
Locality. Khatanga Depression, Nordvik Peninsula, outcrop 33, layers 37–56, Berriasian–Lower Valanginian, Bojarkia meseznikovi ammonite Zone–lower part of Neotollia klimovskiensis ammonite Zone; Ust’- Yenisei Region, borehole Severo-Vologochanskaya 18, 984.3–977.0 m, upper Berriasian–lower Lower Valanginian.
Material. More than 20 specimens of good or adequate preservation.