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Trithyrodinium trendalii
Trithyrodinium trendallii (Cookson & Eisenack, 1970) Pavlishina 1995; Emendation: Pavlishina, 1995, p.138–139, as Trithyrodinium trendallii.
Originally Ascodinium?, subsequently Subtilisphaera?, thirdly and now Trithyrodinium
Holotype: Cookson and Eisenack, 1970, pl.12, fig.5
Locus typicus: Madura No. 1 Bore, Eucla Basin, Western Australia
Stratum typicum: Senonian? Albian-Cenomanian
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Original description: Cookson and Eisenack, 1970, p.145: Ascodinium trendallii
Shell distinctly longer than broad, rather thin-walled, untabulated and very finely and inconspicuously dotted, with a bluntly pointed median apical projection and a downwardly slanting antapex with a short + sharply pointed projection on the right-hand side. A well-developed subequatorial girdle delimits a longer epitheca from a shorter hypotheca, its ends on the ventral surface being widely separated.
The internal capsule, which is distinctly oval in shape and relatively large, extends to the outer wall of the hypotheca but not quite to that of the epitheca. Its wall appears to be somewhat thicker than that of the shell. On the ventral surface of the hypotheca, between the ends of the girdle, the longitudinal wavy thickening, probably associated with the flagellum pore, is usually prominent. An archeopyle has not been observed.
Dimensions: Holotype: Overall length c. 70 Á, overall width 35 Á, internal capsule c. 38 x 30 Á. Range: length c. 67-93 Á, breadth c. 33-50 Á.
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Description: Pavlishina 1995, p. 138-139
Cysts bicavate to circumcavate. Pericyst outline is elongated. The epipericoel is prolongated into a long apical horn. The hypopericoel is with two antapical horns, one of them always is reduced. The endocyst is subspherical. Percingulum is prominent in all specimens, epicyst is longer than hypocyst. The periphragm is smooth, while the endophragm is more thick and finely granulated. The archeopyle is intercalary, type 31/31. The endoperculum often is separated into individual paraplates. Endopercular piece configuration is standard (sensu May & Benson, 1979). The 2a paraplate is hexagonal, thus forming a standard anterior intercalary series. All three paraplates make contact with the apical series. Isolated endocysts are also common.
Remarks. Trithyrodinium trendalli differs from T. druggii Stone, 1973 by its well recognizable cingulum and sulcus.
Stratigraphic range. Albian, Cenomanian to Senonian in Australia.
Occurrence. Komunari section, Mezdra Formation, samples 329, 330.
Originally Ascodinium?, subsequently Subtilisphaera?, thirdly and now Trithyrodinium
Holotype: Cookson and Eisenack, 1970, pl.12, fig.5
Locus typicus: Madura No. 1 Bore, Eucla Basin, Western Australia
Stratum typicum: Senonian? Albian-Cenomanian
------------------------------
Original description: Cookson and Eisenack, 1970, p.145: Ascodinium trendallii
Shell distinctly longer than broad, rather thin-walled, untabulated and very finely and inconspicuously dotted, with a bluntly pointed median apical projection and a downwardly slanting antapex with a short + sharply pointed projection on the right-hand side. A well-developed subequatorial girdle delimits a longer epitheca from a shorter hypotheca, its ends on the ventral surface being widely separated.
The internal capsule, which is distinctly oval in shape and relatively large, extends to the outer wall of the hypotheca but not quite to that of the epitheca. Its wall appears to be somewhat thicker than that of the shell. On the ventral surface of the hypotheca, between the ends of the girdle, the longitudinal wavy thickening, probably associated with the flagellum pore, is usually prominent. An archeopyle has not been observed.
Dimensions: Holotype: Overall length c. 70 Á, overall width 35 Á, internal capsule c. 38 x 30 Á. Range: length c. 67-93 Á, breadth c. 33-50 Á.
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Description: Pavlishina 1995, p. 138-139
Cysts bicavate to circumcavate. Pericyst outline is elongated. The epipericoel is prolongated into a long apical horn. The hypopericoel is with two antapical horns, one of them always is reduced. The endocyst is subspherical. Percingulum is prominent in all specimens, epicyst is longer than hypocyst. The periphragm is smooth, while the endophragm is more thick and finely granulated. The archeopyle is intercalary, type 31/31. The endoperculum often is separated into individual paraplates. Endopercular piece configuration is standard (sensu May & Benson, 1979). The 2a paraplate is hexagonal, thus forming a standard anterior intercalary series. All three paraplates make contact with the apical series. Isolated endocysts are also common.
Remarks. Trithyrodinium trendalli differs from T. druggii Stone, 1973 by its well recognizable cingulum and sulcus.
Stratigraphic range. Albian, Cenomanian to Senonian in Australia.
Occurrence. Komunari section, Mezdra Formation, samples 329, 330.