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Soaniella sibirica
From Fensome et al., 2019:
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Original description Vasilyeva, 2012:
The name comes from sibiricus (lat.) – Siberian (according to location).
Diagnosis. Peridinoid cornucopia cyst of medium size. Pericyst is pentagonal with straight lateral walls. Small apical horn of rounded shape is developed. Antapical horns are asymmetrical, the right one is usually longer than the left. Periphragma is thin, coarse-grained. Endocyst is rounded-pentagonal, tightly adjacent to pericyst. Pericoel in the area of apical and one antapical horn. Periarcheopylus is combined, type 3I3P(1a-3a+3"-5") or A3I3P(3'+1a-3a+3"-5"). Operculum is usually free. Parasulcus is distinct, triangular in shape. The paratabulation of the cyst is reflected by the structure of the archeopyle, cingulum and sulcus.
Diagnosis. Cornucavate peridiniacean cysts of intermediate size. Pericyst shape is pentagonal with straight sides. Epicyst has short blunt apical horn. Antapical horns are asymmetrical, right of which is longer. Periphragm is thin, coarse granulated. Endocyst of round-pentagonal shape; it is closely appressed pericyst except zone of apical and right antapical. Periarcheopyle is combinated, type 3I3P(1a-3a+3"+5") or A3I3P(3'+1a-3a+3"-5").
Description. The peridinoid cornucopia cyst is weakly compressed in the dorsoventral direction and of medium size. The pericyst is distinctly pentagonal in shape. The lateral sides of the epicyst and hypocyst are straight. The epicyst is equal to or slightly short.
hypocysts. On the epicyst a small triangular apical horn is developed, slightly rounded in shape. On the hypocyst two antapical horns are formed, the right one is usually longer. The periphragm is thin, coarse-grained. Granularity is uneven, the grains often merge. The endocyst is rounded-pentagonal, repeats the shape of the percyst and fits tightly to it. The pericyst is distinguishable only in the area of the apical and one antapical horns. The endophragm is thin, probably smooth. The cyst is cornucopia. The paracingulum is distinct, on the lateral sides it is in the form of a small groove, on the dorsal and ventral sides of the cyst it is in the form of a double sinuous suture or folds. The periarchaeopile is of a combined intercalary-precingular type, sometimes involving the apical plate, type 3I3P(1a-3a+3"-5") or A3I3P(3'+1a-3a+3"-5"). The operculum is usually free. The parasulcus is expressed by a distinct triangular depression on the ventral side of the cyst. The paratabulation of the cyst is reflected by the structure of the archaeopile, cingulum and sulcus.
Holotype. Plate 2, Fig. 10. Ref. K14/130–25S.
Location. Well K-14 (Komsomolskaya), Komsomolsky settlement, Khanty-Mansiysk Autonomous Okrug, Russia.
Dimensions (μm). Holotype: pericyst length – 72, pericyst width – 64. Other specimens (5 specimens): pericyst length – 68–73, pericyst width – 60–66.
Comparison. The species Soaniella sibirica sp. ÿov. differs from the type species Soaniella granulata Vozzh. in the pentagonal shape of the pericyst, straight lateral walls, and the shape of the apical horn.
Distribution. Russia, Western Siberia, upper reaches of the Konda River, Nyurol Formation. Eocene (Ypresian-Lutetian).
Note: The species Soaniella sibirica sp. nov. usually retains the cyst shape well after formation.
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Original description Vasilyeva, 2012:
The name comes from sibiricus (lat.) – Siberian (according to location).
Diagnosis. Peridinoid cornucopia cyst of medium size. Pericyst is pentagonal with straight lateral walls. Small apical horn of rounded shape is developed. Antapical horns are asymmetrical, the right one is usually longer than the left. Periphragma is thin, coarse-grained. Endocyst is rounded-pentagonal, tightly adjacent to pericyst. Pericoel in the area of apical and one antapical horn. Periarcheopylus is combined, type 3I3P(1a-3a+3"-5") or A3I3P(3'+1a-3a+3"-5"). Operculum is usually free. Parasulcus is distinct, triangular in shape. The paratabulation of the cyst is reflected by the structure of the archeopyle, cingulum and sulcus.
Diagnosis. Cornucavate peridiniacean cysts of intermediate size. Pericyst shape is pentagonal with straight sides. Epicyst has short blunt apical horn. Antapical horns are asymmetrical, right of which is longer. Periphragm is thin, coarse granulated. Endocyst of round-pentagonal shape; it is closely appressed pericyst except zone of apical and right antapical. Periarcheopyle is combinated, type 3I3P(1a-3a+3"+5") or A3I3P(3'+1a-3a+3"-5").
Description. The peridinoid cornucopia cyst is weakly compressed in the dorsoventral direction and of medium size. The pericyst is distinctly pentagonal in shape. The lateral sides of the epicyst and hypocyst are straight. The epicyst is equal to or slightly short.
hypocysts. On the epicyst a small triangular apical horn is developed, slightly rounded in shape. On the hypocyst two antapical horns are formed, the right one is usually longer. The periphragm is thin, coarse-grained. Granularity is uneven, the grains often merge. The endocyst is rounded-pentagonal, repeats the shape of the percyst and fits tightly to it. The pericyst is distinguishable only in the area of the apical and one antapical horns. The endophragm is thin, probably smooth. The cyst is cornucopia. The paracingulum is distinct, on the lateral sides it is in the form of a small groove, on the dorsal and ventral sides of the cyst it is in the form of a double sinuous suture or folds. The periarchaeopile is of a combined intercalary-precingular type, sometimes involving the apical plate, type 3I3P(1a-3a+3"-5") or A3I3P(3'+1a-3a+3"-5"). The operculum is usually free. The parasulcus is expressed by a distinct triangular depression on the ventral side of the cyst. The paratabulation of the cyst is reflected by the structure of the archaeopile, cingulum and sulcus.
Holotype. Plate 2, Fig. 10. Ref. K14/130–25S.
Location. Well K-14 (Komsomolskaya), Komsomolsky settlement, Khanty-Mansiysk Autonomous Okrug, Russia.
Dimensions (μm). Holotype: pericyst length – 72, pericyst width – 64. Other specimens (5 specimens): pericyst length – 68–73, pericyst width – 60–66.
Comparison. The species Soaniella sibirica sp. ÿov. differs from the type species Soaniella granulata Vozzh. in the pentagonal shape of the pericyst, straight lateral walls, and the shape of the apical horn.
Distribution. Russia, Western Siberia, upper reaches of the Konda River, Nyurol Formation. Eocene (Ypresian-Lutetian).
Note: The species Soaniella sibirica sp. nov. usually retains the cyst shape well after formation.