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Carpatella rossica
Carpatella rossica, Iakovleva, 2019
Holotype: . Plate 1, figs 1–5; Slide M-60.1-2. England Finder reference M47/3, Iakovleva, A. I. 2019
Age: Late Paleocene - middle Eocene
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Original description: [Iakovleva, 2019]:
Diagnosis:
An ovodial to spheroidal, proximate, acavate gonyaulacoidean cyst with single, very short apical and antapical horns.
Wall relatively thick (~5 μm).
Archeopyle precingular 3’’, operculum may be free or in place.
Tabulation expressed mostly by the archeopyle and (quite faintly) by the cingulum that has a strong overhang, and only rarely by plates 2’’, 2’’’ and 3’’’; single intratabular boundaries very rarely observed.
Description:
A gonyaulacoidean dinoflagellate cyst of intermediate size, ovoidal to spheroidal, circular in equatorial section, possessing single and very short solid subtriangular apical and antapical horns with a nipple-like tip. Depending on the orientation of the specimen in the preparation, the antapical horn sometimes appears to be almost invisible.
Horns distinctly thinner than the general cyst wall.
Cyst wall: consists of two layers: pedium extremely thin and smooth; luxuria quite thick (~5–7 μm) and spongy. Inner and outer layers tightly compressed. Nevertheless, occasionally the presence of a thin inner layer may be inferred when the inner layer is visually pressed into the luxuria in the antapical area (Plate 2, fig. 10).
Paratabulation: mostly indicated by the precingular archeopyle (Type P) comprising paraplate 3’’ only, and by a shallowly furrowed cingulum flanked by low smooth ridges on the anterior and posterior sides; only very rarely plates 2’’, 2’’’ and 3’’’ and single intratabular boundaries may be observed.
Operculum: rounded pentagonal; may be free or in place.
Dimensions:
Holotype: total length 72 μm; total width 70 μm; length of apical horn 6.4 μm; length of antapical horn 6 μm; thickness of wall 5 μm.
Paratype 1: total length 80 μm; total width 77 μm; length of apical horn 6 μm; length of antapical horn 6 μm; thickness of wall 5.5 μm.
Paratype 2: total length 83 μm; total width 73 μm; length of apical horn 6 μm; antapical horn not visible; thickness of wall 7 μm.
Dimensions of measured specimens: total length 69–83 μm (mean 75 μm); total width 68–77 μm (mean 72 μm); length of apical horn 4–7 μm (mean 6 μm); length of antapical horn 5–9 μm (mean 6.5 μm); thickness of wall 5–7 μm (mean 6 μm).
Specimens measured: 13
Affinities:
Carpatella rossica sp. nov. differs from the type-species Carpatella cornuta by its smaller cyst, smaller apical and antapical horns, and faint paratabulation expressed mainly (under LM) by the archeopyle, cingulum and parasutures (e.g. Plate 2, fig. 1); single intratabular linear features are very rarely observed. Carpatella rossica sp. nov. differs from Carpatella septata and Carpatella truncata by its short horns, the absence of reticulate surface ornamentation and intratabular truncate processes. It is more difficult to compare Carpatella rossica sp. nov. with species described by He Chengquan (1984, 1991), except for the description of Carpatella sinensis. Based only on the illustrations of C. circularis, C. scabrota, C. humera, C. sinensis, C. lamprota and C. fusiformis provided by He Chengquan (1984, 1991), Carpatella rossica sp. nov. differs by the absence of any parasutural ornamentation and by its more spherical shape, smaller horns and smoother wall surface.
Carpatella rossica sp. nov. bears a resemblance to Apteodinium crassum Slimani & Louwye 2013, which is also a subspherical cyst of intermediate size and has a finely spongeous outer layer and a small subtriangular and bulbous apical horn with a nipple-like tip.
Carpatella rossica sp. nov. is clearly distinguished from Apteodinium crassum by the presence of the antapical horn and thinner outer layer.
Holotype: . Plate 1, figs 1–5; Slide M-60.1-2. England Finder reference M47/3, Iakovleva, A. I. 2019
Age: Late Paleocene - middle Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Iakovleva, 2019]:
Diagnosis:
An ovodial to spheroidal, proximate, acavate gonyaulacoidean cyst with single, very short apical and antapical horns.
Wall relatively thick (~5 μm).
Archeopyle precingular 3’’, operculum may be free or in place.
Tabulation expressed mostly by the archeopyle and (quite faintly) by the cingulum that has a strong overhang, and only rarely by plates 2’’, 2’’’ and 3’’’; single intratabular boundaries very rarely observed.
Description:
A gonyaulacoidean dinoflagellate cyst of intermediate size, ovoidal to spheroidal, circular in equatorial section, possessing single and very short solid subtriangular apical and antapical horns with a nipple-like tip. Depending on the orientation of the specimen in the preparation, the antapical horn sometimes appears to be almost invisible.
Horns distinctly thinner than the general cyst wall.
Cyst wall: consists of two layers: pedium extremely thin and smooth; luxuria quite thick (~5–7 μm) and spongy. Inner and outer layers tightly compressed. Nevertheless, occasionally the presence of a thin inner layer may be inferred when the inner layer is visually pressed into the luxuria in the antapical area (Plate 2, fig. 10).
Paratabulation: mostly indicated by the precingular archeopyle (Type P) comprising paraplate 3’’ only, and by a shallowly furrowed cingulum flanked by low smooth ridges on the anterior and posterior sides; only very rarely plates 2’’, 2’’’ and 3’’’ and single intratabular boundaries may be observed.
Operculum: rounded pentagonal; may be free or in place.
Dimensions:
Holotype: total length 72 μm; total width 70 μm; length of apical horn 6.4 μm; length of antapical horn 6 μm; thickness of wall 5 μm.
Paratype 1: total length 80 μm; total width 77 μm; length of apical horn 6 μm; length of antapical horn 6 μm; thickness of wall 5.5 μm.
Paratype 2: total length 83 μm; total width 73 μm; length of apical horn 6 μm; antapical horn not visible; thickness of wall 7 μm.
Dimensions of measured specimens: total length 69–83 μm (mean 75 μm); total width 68–77 μm (mean 72 μm); length of apical horn 4–7 μm (mean 6 μm); length of antapical horn 5–9 μm (mean 6.5 μm); thickness of wall 5–7 μm (mean 6 μm).
Specimens measured: 13
Affinities:
Carpatella rossica sp. nov. differs from the type-species Carpatella cornuta by its smaller cyst, smaller apical and antapical horns, and faint paratabulation expressed mainly (under LM) by the archeopyle, cingulum and parasutures (e.g. Plate 2, fig. 1); single intratabular linear features are very rarely observed. Carpatella rossica sp. nov. differs from Carpatella septata and Carpatella truncata by its short horns, the absence of reticulate surface ornamentation and intratabular truncate processes. It is more difficult to compare Carpatella rossica sp. nov. with species described by He Chengquan (1984, 1991), except for the description of Carpatella sinensis. Based only on the illustrations of C. circularis, C. scabrota, C. humera, C. sinensis, C. lamprota and C. fusiformis provided by He Chengquan (1984, 1991), Carpatella rossica sp. nov. differs by the absence of any parasutural ornamentation and by its more spherical shape, smaller horns and smoother wall surface.
Carpatella rossica sp. nov. bears a resemblance to Apteodinium crassum Slimani & Louwye 2013, which is also a subspherical cyst of intermediate size and has a finely spongeous outer layer and a small subtriangular and bulbous apical horn with a nipple-like tip.
Carpatella rossica sp. nov. is clearly distinguished from Apteodinium crassum by the presence of the antapical horn and thinner outer layer.