Back
Trithyrodinium conservatum
From Fensome et al., 2019:
Trithyrodinium conservatum Fensome et al., 2016b, p.74, pl.15, figs.9–14.
Holotype: Nøhr-Hansen, 2003, pl.3, fig.6; Fensome et al., 2016b, pl.15, fig.12.
Age: last occurrence, Lutetian.
---------------------------------------------------------------------------------------------------
Original description Fensome et al., 2016b:
2003 Deflandrea sp.1 Nøhr-Hansen, plate 3, figs 4–6.
Holotype. Plate 15, fig. 12 and Nøhr-Hansen (2003, plate 3, fig. 6), from a sidewall-core sample at 1155 m in Ikermiut 1, MGHU no. 26502, sample 04E006504, slide 2, co-ordinates 36.0 × 97.1, England Finder U36/1. Pericyst length 60 μm, width 63 μm, endocyst length 44 μm, width 52 μm. The age determined for the sample from which the holotype was recovered is Lutetian.
Etymology. The epithet is from the Latin conservatus, meaning retain or conserve, in reference to the constant presence of the pericyst.
Description. A species of Trithyrodinium with a commonly rounded but sometimes ovoidal pericyst that is always present. The endocyst generally mimics the shape of the pericyst. As a rule the cyst is circumcavate, but the endocyst may occasionally be in partial contact with the pericyst. The periphragm and endophragm are both thin, at the most slightly over 1 μm thick. The periphragm varies from laevigate (the usual condition), to faintly granulate or verrucate. The I to 3I archaeopyle is formed from the loss of one to three intercalary plates individually, any of which can remain attached posteriorly.
Size. Pericyst length 48–60 μm, width 49–65 μm, endocyst length 44–51 μm, width 43–56 μm; seven specimens measured.
Age. LO: Lutetian. Not plotted.
Remarks. Trithyrodinium? conservatum is unusual in that the pericyst is always preserved. When the pericyst has a subdued granulate or verrucate ornamentation, this tends to be restricted to the mid-dorsal and mid-ventral regions. Folds are consistently present on the pericyst but appear to be random. The exact nature of the archaeopyle is unclear. In some specimens its polygonal shape appears to indicate that multiple plates are missing, but in others it appears to reflect loss of a single intercalary plate. Because of the uncertainty regarding the archaeopyle, the species is only assigned questionably to Trithyrodinium.
Trithyrodinium conservatum Fensome et al., 2016b, p.74, pl.15, figs.9–14.
Holotype: Nøhr-Hansen, 2003, pl.3, fig.6; Fensome et al., 2016b, pl.15, fig.12.
Age: last occurrence, Lutetian.
---------------------------------------------------------------------------------------------------
Original description Fensome et al., 2016b:
2003 Deflandrea sp.1 Nøhr-Hansen, plate 3, figs 4–6.
Holotype. Plate 15, fig. 12 and Nøhr-Hansen (2003, plate 3, fig. 6), from a sidewall-core sample at 1155 m in Ikermiut 1, MGHU no. 26502, sample 04E006504, slide 2, co-ordinates 36.0 × 97.1, England Finder U36/1. Pericyst length 60 μm, width 63 μm, endocyst length 44 μm, width 52 μm. The age determined for the sample from which the holotype was recovered is Lutetian.
Etymology. The epithet is from the Latin conservatus, meaning retain or conserve, in reference to the constant presence of the pericyst.
Description. A species of Trithyrodinium with a commonly rounded but sometimes ovoidal pericyst that is always present. The endocyst generally mimics the shape of the pericyst. As a rule the cyst is circumcavate, but the endocyst may occasionally be in partial contact with the pericyst. The periphragm and endophragm are both thin, at the most slightly over 1 μm thick. The periphragm varies from laevigate (the usual condition), to faintly granulate or verrucate. The I to 3I archaeopyle is formed from the loss of one to three intercalary plates individually, any of which can remain attached posteriorly.
Size. Pericyst length 48–60 μm, width 49–65 μm, endocyst length 44–51 μm, width 43–56 μm; seven specimens measured.
Age. LO: Lutetian. Not plotted.
Remarks. Trithyrodinium? conservatum is unusual in that the pericyst is always preserved. When the pericyst has a subdued granulate or verrucate ornamentation, this tends to be restricted to the mid-dorsal and mid-ventral regions. Folds are consistently present on the pericyst but appear to be random. The exact nature of the archaeopyle is unclear. In some specimens its polygonal shape appears to indicate that multiple plates are missing, but in others it appears to reflect loss of a single intercalary plate. Because of the uncertainty regarding the archaeopyle, the species is only assigned questionably to Trithyrodinium.