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Trithyrodinium unicorniculum
Trithyrodinium unicorniculum Davey, 1975
Holotype: Davey, 1975, pl.3, fig.6
Locus typicus: Ghana
Stratum typicum: Senonian (?Campanian)
Original diagnosis: Davey, 1975, p.158-159
Ovoidal cyst possessing a thick-walled, densely granular inner body and a thin, closely-fitting periphragm. The latter is detached from the inner body only in the apical region, where it forms a short conical apical horn, and in the antapical region, where a similarly shaped antapical horn is present. This is, however, asymmetrically placed wlth respect to the cyst axis and represents the left horn. When the cingulum is discernible it is defined by two extremely faint ridges; the sulcus is represented by a sunken longitudinal groove. An archaeopyle has never been observed. Rarely, the anterior intercalary plates on the inner body are seen to be displaced and extremely rarely are dislodged to give a large opening corresponding to plates 1a, 2a and 3a.
Dimensions: Holotype - Range
Overall length: 91 µm - 62(87)93 µm
Overall width: 53 µm - 49(53)59 µm
Original description: Davey, 1975, p.159
The archaeopyle probably occupies the anterior intercalary plate 2a position but is extremely difficult to observe due to the thinness of the periphragm. The anterior intercalary plates of the inner body are joined on their cingular margin, and after excystment had taken place normally returned to their original position. Hence the inner body usually appears to be entire.
Holotype: Davey, 1975, pl.3, fig.6
Locus typicus: Ghana
Stratum typicum: Senonian (?Campanian)
Original diagnosis: Davey, 1975, p.158-159
Ovoidal cyst possessing a thick-walled, densely granular inner body and a thin, closely-fitting periphragm. The latter is detached from the inner body only in the apical region, where it forms a short conical apical horn, and in the antapical region, where a similarly shaped antapical horn is present. This is, however, asymmetrically placed wlth respect to the cyst axis and represents the left horn. When the cingulum is discernible it is defined by two extremely faint ridges; the sulcus is represented by a sunken longitudinal groove. An archaeopyle has never been observed. Rarely, the anterior intercalary plates on the inner body are seen to be displaced and extremely rarely are dislodged to give a large opening corresponding to plates 1a, 2a and 3a.
Dimensions: Holotype - Range
Overall length: 91 µm - 62(87)93 µm
Overall width: 53 µm - 49(53)59 µm
Original description: Davey, 1975, p.159
The archaeopyle probably occupies the anterior intercalary plate 2a position but is extremely difficult to observe due to the thinness of the periphragm. The anterior intercalary plates of the inner body are joined on their cingular margin, and after excystment had taken place normally returned to their original position. Hence the inner body usually appears to be entire.