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Hystrichodinium polycheirum
Hystrichodinium polycheirum Heilmann-Clausen and Thomson 1995
Holotype: Heilmann-Clausen and Thomsen 1995: Pl. 11, figs. 7, 8; Text-fig. 16
Paratype 1: Heilmann-Clausen and Thomsen 1995: Pl. 11, fig. 9
Paratype 2: Heilmann-Clausen and Thomsen 1995: Pl. 11, fig. 10
Type locality: Gott clay-pit, Sarstedt, Lower Saxony, Germany.
Type stratum: Sample 88/9, bed 131, Upper Barremian
Original Diagnosis: Heilmann-Clausen and Thomsen 1995, p. 297-298
A skolochorate dinoflagellate cyst. The central body is rounded-biconical or eggshaped. The periphragm is almost smooth, sometimes ornamented with hollow tubercles. A narrow cingulum bordered by low, simple septa is present in an equatorial position. Other paraplate boundaries are occasionally marked by indistinct, low ridges. The processes are situated in polar positions; 3-7 processes occur anterior to the precingular paraplates and between 4 and 11 processes occur posterior to the postcingular paraplates. They appear to be placed in parasutural positions. Rarely a single reduced process has been seen ventrally, near the posterior margin of the paracingulum. The processes are flat and ribbonlike. The breadth may exceed 10 Ám. Distally the processes split into 4-11 blunt-tipped fingers of almost equal length. Most of the processes may thereby resemble arms with hands. The archaeopyle is precingular, type P (3").
Dimensions of holotype: Central body length 48Ám, breadth 50Ám, length of pericyst 86Ám.
Dimensions of measured specimens: Central body length: 48 (52) 54Ám Central body breadth: 36 (48) 55Ám Length of pericyst: 86 (92) 101Ám Length of processes: 16-31Ám, (6 specimens measured)
Comparison: The flexible, ribbon-like process-shafts in H. polycheirum show that it is phylogenetically related to other species in the genus Hystrichodinium. H. oligacanthum DEFLANDRE & COOKSON, 1955 and H. ? amphiacanthum COOKSON & EISENACK, 1958 have a similar distribution of the processes, but their processes are simple, without "fingers".
The occasionally occurring hollow tubercles on the central body resemble those in Hystrichodinium pulchrum.
Holotype: Heilmann-Clausen and Thomsen 1995: Pl. 11, figs. 7, 8; Text-fig. 16
Paratype 1: Heilmann-Clausen and Thomsen 1995: Pl. 11, fig. 9
Paratype 2: Heilmann-Clausen and Thomsen 1995: Pl. 11, fig. 10
Type locality: Gott clay-pit, Sarstedt, Lower Saxony, Germany.
Type stratum: Sample 88/9, bed 131, Upper Barremian
Original Diagnosis: Heilmann-Clausen and Thomsen 1995, p. 297-298
A skolochorate dinoflagellate cyst. The central body is rounded-biconical or eggshaped. The periphragm is almost smooth, sometimes ornamented with hollow tubercles. A narrow cingulum bordered by low, simple septa is present in an equatorial position. Other paraplate boundaries are occasionally marked by indistinct, low ridges. The processes are situated in polar positions; 3-7 processes occur anterior to the precingular paraplates and between 4 and 11 processes occur posterior to the postcingular paraplates. They appear to be placed in parasutural positions. Rarely a single reduced process has been seen ventrally, near the posterior margin of the paracingulum. The processes are flat and ribbonlike. The breadth may exceed 10 Ám. Distally the processes split into 4-11 blunt-tipped fingers of almost equal length. Most of the processes may thereby resemble arms with hands. The archaeopyle is precingular, type P (3").
Dimensions of holotype: Central body length 48Ám, breadth 50Ám, length of pericyst 86Ám.
Dimensions of measured specimens: Central body length: 48 (52) 54Ám Central body breadth: 36 (48) 55Ám Length of pericyst: 86 (92) 101Ám Length of processes: 16-31Ám, (6 specimens measured)
Comparison: The flexible, ribbon-like process-shafts in H. polycheirum show that it is phylogenetically related to other species in the genus Hystrichodinium. H. oligacanthum DEFLANDRE & COOKSON, 1955 and H. ? amphiacanthum COOKSON & EISENACK, 1958 have a similar distribution of the processes, but their processes are simple, without "fingers".
The occasionally occurring hollow tubercles on the central body resemble those in Hystrichodinium pulchrum.