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Litosphaeridium striatoconus
Litosphaeridium "?striatoconum" (Deflandre and Cookson, 1955, p.275, pl.2, fig.10; text-fig.36) Sarjeant, 1969, p.14.
NOW Conosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Litosphaeridium?, fourthly (and now) Conosphaeridium. Questionable assignment: Sarjeant (1969, p.14).
Holotype: Deflandre and Cookson, 1955, text-fig.36.
Age: mid Senonian.
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Original description: [Deflandre and Cookson, 1955]:
HYSTRICHOSPHAERIDIUM STRIATOCONUS sp. nov.
Fig. 36; Plate 2, Fig. 10
Upper Cretaceous (Senonian): Gingin, W.A.
Shell rather robust and thick-walled, globular to spheroidal, ornamented with about 20 bluntly pointed conical processes, the apex of which is normally closed but is frequently broken off leaving a direct opening into the process. Each cone is provided with a number of strong ribs that are thicker at the base and taper tOwards but do not reach the apex: some of the ribs extend to about half the height of the cone, others
stop 3-4 from the summit. The shell generally has a polygonal or rounded opening. Surface of shell smooth.
Dimensions. - Shell alone 52-57 μ, cones 12-18 μ long.
At the base of each cone a distinct circular line corresponding to the interior wall of the cone (the exterior contour is strongly indented by the
ribs) can be seen, but it has not been possible to decide fronm the present preparations whether or not the cones communicate with the interior of the shell. All the specimens have become strongly coloured by the safranin in the mounting medium and show neither a clear interruption nor a thinning of the shell in the region of the cones.
H. striatoconus is relatively abundant in the Lower Greensand at Gingin; it is distinctly different from all known species of Hystrichosphaeridium.
NOW Conosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Litosphaeridium?, fourthly (and now) Conosphaeridium. Questionable assignment: Sarjeant (1969, p.14).
Holotype: Deflandre and Cookson, 1955, text-fig.36.
Age: mid Senonian.
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Original description: [Deflandre and Cookson, 1955]:
HYSTRICHOSPHAERIDIUM STRIATOCONUS sp. nov.
Fig. 36; Plate 2, Fig. 10
Upper Cretaceous (Senonian): Gingin, W.A.
Shell rather robust and thick-walled, globular to spheroidal, ornamented with about 20 bluntly pointed conical processes, the apex of which is normally closed but is frequently broken off leaving a direct opening into the process. Each cone is provided with a number of strong ribs that are thicker at the base and taper tOwards but do not reach the apex: some of the ribs extend to about half the height of the cone, others
stop 3-4 from the summit. The shell generally has a polygonal or rounded opening. Surface of shell smooth.
Dimensions. - Shell alone 52-57 μ, cones 12-18 μ long.
At the base of each cone a distinct circular line corresponding to the interior wall of the cone (the exterior contour is strongly indented by the
ribs) can be seen, but it has not been possible to decide fronm the present preparations whether or not the cones communicate with the interior of the shell. All the specimens have become strongly coloured by the safranin in the mounting medium and show neither a clear interruption nor a thinning of the shell in the region of the cones.
H. striatoconus is relatively abundant in the Lower Greensand at Gingin; it is distinctly different from all known species of Hystrichosphaeridium.