Back
Nematosphaeropsis singularis
Nematosphaeropsis singularis Davey, 1979
Holotype: Davey, 1979, pl.5, fig.14
Age: Aptian-Albian
Original description (davey, 1979):
Nematosphaeropsis singularis sp. nov. (Plate 5, Figures 6, 10, 14)
Derivation of name: Latin, singularis, different — with reference to the unusual processes.
Diagnosis: The cyst is subspherical and is composed of a thin, lightly granular wall which bears variably shaped processes arising from low parasutural ridges. Both gonal and parasutural processes are present and vary from being broadly membranous to being quite delicate; branching may occur. All are of about equal height on an individual. Distally, each process expands before bifurcating or trifurcating to give rise to weak, generally smooth trabeculae which link adjacent processes along parasutural ridges. Although the latter are usually present, it is not possible to define the complete tabulation. An archeopyle is normally developed and appears to be precingular (3").
Holotype: MPK 1739, DSDP Leg 48, Hole 402A, Sample 25-5, 5-8 cm. Aptian, northern Bay of Biscay.
Dimensions:
Holotype – Central body diameter 42x50 µm, height of processes 6-12 µm
Range – Central body diameter 30 (38) 50 µm, height of processes 7 (10) 15 µm (maxima)
Description: Most of the processes are of the relatively simple, parallel-sided type which widen distally and are reminiscent of those occurring in the genera Spiniferites and Achomosphaera. However some processes are irregular and have both proximal and distal branching. The trabeculae are variably developed but this could partly be because of breakage.
Remarks: The variable form of the processes and the rather weak trabeculae distinguish N. singularis sp. nov. from other species in this genus. N. singularis has tentatively been assigned to Nematosphaeropsis because of its overall morphology. A clear Gonyaulacean tabulation has not been deciphered and the exact form of the archeopyle still remains in doubt. N. singularis has a last stratigraphic occurrence in the uppermost Aptian (?basal Albian) in Hole 400A.
Holotype: Davey, 1979, pl.5, fig.14
Age: Aptian-Albian
Original description (davey, 1979):
Nematosphaeropsis singularis sp. nov. (Plate 5, Figures 6, 10, 14)
Derivation of name: Latin, singularis, different — with reference to the unusual processes.
Diagnosis: The cyst is subspherical and is composed of a thin, lightly granular wall which bears variably shaped processes arising from low parasutural ridges. Both gonal and parasutural processes are present and vary from being broadly membranous to being quite delicate; branching may occur. All are of about equal height on an individual. Distally, each process expands before bifurcating or trifurcating to give rise to weak, generally smooth trabeculae which link adjacent processes along parasutural ridges. Although the latter are usually present, it is not possible to define the complete tabulation. An archeopyle is normally developed and appears to be precingular (3").
Holotype: MPK 1739, DSDP Leg 48, Hole 402A, Sample 25-5, 5-8 cm. Aptian, northern Bay of Biscay.
Dimensions:
Holotype – Central body diameter 42x50 µm, height of processes 6-12 µm
Range – Central body diameter 30 (38) 50 µm, height of processes 7 (10) 15 µm (maxima)
Description: Most of the processes are of the relatively simple, parallel-sided type which widen distally and are reminiscent of those occurring in the genera Spiniferites and Achomosphaera. However some processes are irregular and have both proximal and distal branching. The trabeculae are variably developed but this could partly be because of breakage.
Remarks: The variable form of the processes and the rather weak trabeculae distinguish N. singularis sp. nov. from other species in this genus. N. singularis has tentatively been assigned to Nematosphaeropsis because of its overall morphology. A clear Gonyaulacean tabulation has not been deciphered and the exact form of the archeopyle still remains in doubt. N. singularis has a last stratigraphic occurrence in the uppermost Aptian (?basal Albian) in Hole 400A.