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Trithyrodinium verrucatum
Trithyrodinium verrucatum sp. nov., Vieira and Mahdi, 2021
Holotype: Plate 8, figure 1, Vieira and Mahdi, 2021
Type locality: Ormen Lange field, Møre Basin (Norway)
Stratigraphic extent: Early Danian
Original description: Vieira and Mahdi, 2021
Diagnosis:
Peridinioid dinoflagellate cysts. The cyst wall is composed of two layers: the thin and transparent periphragm and a thick endophragm bearing numerous non-tabular, spherical to subspherical verrucae of low to moderate relief.
Description:
Proximate peridiniacean cysts, bicavate to circumcavate, subspherical to elliptical in shape.
Archaeopyle: intercalary Type 3I; the operculum is occasionally present and sporadically the opercular pieces can be seen inside the cyst.
Wall: Cyst composed of two closely appressed layers; the endophragm is relatively thick (up to 4 µm), covered with numerous spherical to subspherical verrucae of low to moderate relief, 4–10 µm in diameter. The periphragm is thin and hyaline with a short blunt apical horn (4–15 µm) and one or two barely developed unequal antapical horns.
Dimensions:
Central body length 55 (63) 71 µm, width 52 (63) 71 µm, length of apical horn 5 (9) 14 µm.
20 specimens measured
Affinities/Comparison:
This new species possesses spherical to subspherical thick verrucae of variable size; this diagnostic feature differentiates it from other species within the genus. Trithyrodinium evittii and T. vermiculatum lack the verrucate ornamentation. It also differs from T. suspectum in having thinner wall layers composed of rod-shaped elements of unequal length.
Holotype: Plate 8, figure 1, Vieira and Mahdi, 2021
Type locality: Ormen Lange field, Møre Basin (Norway)
Stratigraphic extent: Early Danian
Original description: Vieira and Mahdi, 2021
Diagnosis:
Peridinioid dinoflagellate cysts. The cyst wall is composed of two layers: the thin and transparent periphragm and a thick endophragm bearing numerous non-tabular, spherical to subspherical verrucae of low to moderate relief.
Description:
Proximate peridiniacean cysts, bicavate to circumcavate, subspherical to elliptical in shape.
Archaeopyle: intercalary Type 3I; the operculum is occasionally present and sporadically the opercular pieces can be seen inside the cyst.
Wall: Cyst composed of two closely appressed layers; the endophragm is relatively thick (up to 4 µm), covered with numerous spherical to subspherical verrucae of low to moderate relief, 4–10 µm in diameter. The periphragm is thin and hyaline with a short blunt apical horn (4–15 µm) and one or two barely developed unequal antapical horns.
Dimensions:
Central body length 55 (63) 71 µm, width 52 (63) 71 µm, length of apical horn 5 (9) 14 µm.
20 specimens measured
Affinities/Comparison:
This new species possesses spherical to subspherical thick verrucae of variable size; this diagnostic feature differentiates it from other species within the genus. Trithyrodinium evittii and T. vermiculatum lack the verrucate ornamentation. It also differs from T. suspectum in having thinner wall layers composed of rod-shaped elements of unequal length.