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Operculodinium centrocarpum var. centrocarpum
Operculodinium centrocarpum var. centrocarpum.
Autonym
Holotype: Deflandre and Cookson, 1955, pl.8, figs.3-4
Locus typicus: Balcombe Bay, Victoria, Australia
Stratum typicum: Middle Miocene
Original description: Deflandre and Cookson, 1955, p. 273: Hystrichosphaeridium centrocarpum
Shell globular, more or less ellipsoidal (probably by deformation), covered with numerous straight, slender processes placed irregulary or with a certain alignment. Processes solid, showing radiating fibrils at their point of insertion on the shell, which is clearly ornamented with a fine reticulum. The slightly widened apices of the processes are fringed with 10 or more small curved spines (this structure is only visible with a high-powered objective).
Dimensions: Diameter of shell 54-80 Ám, length of processes 13-18 Ám, total diameter c. 97-115 Ám.
As a result of the relative thinness of the shell membrane none of the specimens has been completely intact. Most of the examples have a large irregular or more or less angular opening.
Supplemental description: Wall, 1967, p. 111
The test is almost sphaerical and densely ornamented with slender radiating spines whose length (8-16 µm) varies between approximately one-fifth and one-quater of the cell diameter. The dorsal precingular archaeopyle is large and subtrapezoidal. The outer cell wall is microgranular and the immediate spine bases are conical with minute striations. The spine tips bear small hooklets wich are visible only at high magnifications. The spines are aligned in the girdle region but there is no distinct ventral sulcus. The spine arrangement is intratabular, most spines lying alongside the sutural lines.
Dimensions: Caribbean specimens vary from 40 to 56 Ám for the test alone. Miocene specimens may be much larger, with diameters approching 90 Ám.
Affinities:
Deflandre and Cookson, 1955, p. 273: Hystrichosphaeridium centrocarpum
H. centrocarpum, in spite of its generally similar appearance, does not belong to the species group of H. recurvatum Delf. - H. major Lej.-Carp. known from the European Cretaceous flints. In these species the hollow processes have a quite different structure.
Autonym
Holotype: Deflandre and Cookson, 1955, pl.8, figs.3-4
Locus typicus: Balcombe Bay, Victoria, Australia
Stratum typicum: Middle Miocene
Original description: Deflandre and Cookson, 1955, p. 273: Hystrichosphaeridium centrocarpum
Shell globular, more or less ellipsoidal (probably by deformation), covered with numerous straight, slender processes placed irregulary or with a certain alignment. Processes solid, showing radiating fibrils at their point of insertion on the shell, which is clearly ornamented with a fine reticulum. The slightly widened apices of the processes are fringed with 10 or more small curved spines (this structure is only visible with a high-powered objective).
Dimensions: Diameter of shell 54-80 Ám, length of processes 13-18 Ám, total diameter c. 97-115 Ám.
As a result of the relative thinness of the shell membrane none of the specimens has been completely intact. Most of the examples have a large irregular or more or less angular opening.
Supplemental description: Wall, 1967, p. 111
The test is almost sphaerical and densely ornamented with slender radiating spines whose length (8-16 µm) varies between approximately one-fifth and one-quater of the cell diameter. The dorsal precingular archaeopyle is large and subtrapezoidal. The outer cell wall is microgranular and the immediate spine bases are conical with minute striations. The spine tips bear small hooklets wich are visible only at high magnifications. The spines are aligned in the girdle region but there is no distinct ventral sulcus. The spine arrangement is intratabular, most spines lying alongside the sutural lines.
Dimensions: Caribbean specimens vary from 40 to 56 Ám for the test alone. Miocene specimens may be much larger, with diameters approching 90 Ám.
Affinities:
Deflandre and Cookson, 1955, p. 273: Hystrichosphaeridium centrocarpum
H. centrocarpum, in spite of its generally similar appearance, does not belong to the species group of H. recurvatum Delf. - H. major Lej.-Carp. known from the European Cretaceous flints. In these species the hollow processes have a quite different structure.