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Senoniasphaera clavellii
Senoniasphaera clavellii Bailey et al., 1997, p.236,239, figs.4d–h.
Holotype: Bailey et al., 1997, fig.4d (not figs.3d–h ).
Age: late Kimmeridgian.
Original description (Bailey et al., 1997) Senonisphaera clavelli sp. nov. Fig. 3d-h:
Diagnosis : A species of Senoniasphaera, usually bicavate, sometimes circumcavate, with an elongate apical horn. Endocyst subsphaerical, with a pronounced apical protrusion and slight dorso-ventral compression, endophragm relatively thick and may be smooth, scabrate or faintly granular. Pericyst constructed of a thin, pale more or less smooth periphragm, without antapical protrusions, but with an elongate apical horn. Hypocyst usually exhibits a prolate outline, especially the eperiphragm. Paratabulation is faintly, often incompletely expressed on the surface of the periphragm. Archepoyle apical, type [tAI], operculum free or attached. Size range 70-110 µm.
Holotype. Slide 75.3, England Finder ref. S38/3 (University of Sheffield, MSc slides of Varney 1984), Figure 3d.
Type locality: Hen Cliff, near Kimmeridge Bay, Dorset. Kim-meridge Clay Formation, Bed 75 of Cox and Gallois (1981) (near — top autissiodorensis Zone).
Derivation of name. After local celebrity James Clavell, in whose memory an obelisk is built on top of Hen Cliff.
Description. Shape: endocyst subspherical, with slight dorso-ventral compression. Pericyst elongate ovoidal, with a rounded hypocyst, epicyst developed apically into a pronounced elongate horn.
Wall relationships: cyst circumcavate-bicavate, pericoel most developed antapically, reduced laterally and apically, often epicornucavate.
Wail features: endophragm relatively thick (c. 1 µm), with a smooth, scabrate or faintly granular ornament.
Paratabulation: expressed faintly or incompletely on the periphragm as low ridges or thickenings, often emphasised by folding. Paracingulum usually obvious, with other parasutures indistinct.
Archaeopyle: type [tAI], operculum free or attached. Paracingulum: indicated by low ridges or thickenings of the periphragm.
Parasulcus: generally not visible.
Dimensions: pericyst; length 75-110 µm, width 60-65 µm, horn 10-25 µm. Endocyst; length 75-90 µm, width 50-60 µm. Holotype 85 µm X 55 µm overall.
Occurrence. Kimmeridge Clay Formation (Kimmeridgian Pectinatites hudlestoni to Pectinatites pectinatus zones) at Marton (this study), Hounstat Marl, (Kimmeridgian Vir-gatopavlovia fittoni Zone) in Dorset (PM, personal observations), Kimmeridge Clay Formation (Pectinatites autissiodorensis to Pectinatites elegans zones) from Dorset (Varney 1984). The taxon is seen regularly in equivalent sediments from the North Sea and adjacent areas (personal observations).
Holotype: Bailey et al., 1997, fig.4d (not figs.3d–h ).
Age: late Kimmeridgian.
Original description (Bailey et al., 1997) Senonisphaera clavelli sp. nov. Fig. 3d-h:
Diagnosis : A species of Senoniasphaera, usually bicavate, sometimes circumcavate, with an elongate apical horn. Endocyst subsphaerical, with a pronounced apical protrusion and slight dorso-ventral compression, endophragm relatively thick and may be smooth, scabrate or faintly granular. Pericyst constructed of a thin, pale more or less smooth periphragm, without antapical protrusions, but with an elongate apical horn. Hypocyst usually exhibits a prolate outline, especially the eperiphragm. Paratabulation is faintly, often incompletely expressed on the surface of the periphragm. Archepoyle apical, type [tAI], operculum free or attached. Size range 70-110 µm.
Holotype. Slide 75.3, England Finder ref. S38/3 (University of Sheffield, MSc slides of Varney 1984), Figure 3d.
Type locality: Hen Cliff, near Kimmeridge Bay, Dorset. Kim-meridge Clay Formation, Bed 75 of Cox and Gallois (1981) (near — top autissiodorensis Zone).
Derivation of name. After local celebrity James Clavell, in whose memory an obelisk is built on top of Hen Cliff.
Description. Shape: endocyst subspherical, with slight dorso-ventral compression. Pericyst elongate ovoidal, with a rounded hypocyst, epicyst developed apically into a pronounced elongate horn.
Wall relationships: cyst circumcavate-bicavate, pericoel most developed antapically, reduced laterally and apically, often epicornucavate.
Wail features: endophragm relatively thick (c. 1 µm), with a smooth, scabrate or faintly granular ornament.
Paratabulation: expressed faintly or incompletely on the periphragm as low ridges or thickenings, often emphasised by folding. Paracingulum usually obvious, with other parasutures indistinct.
Archaeopyle: type [tAI], operculum free or attached. Paracingulum: indicated by low ridges or thickenings of the periphragm.
Parasulcus: generally not visible.
Dimensions: pericyst; length 75-110 µm, width 60-65 µm, horn 10-25 µm. Endocyst; length 75-90 µm, width 50-60 µm. Holotype 85 µm X 55 µm overall.
Occurrence. Kimmeridge Clay Formation (Kimmeridgian Pectinatites hudlestoni to Pectinatites pectinatus zones) at Marton (this study), Hounstat Marl, (Kimmeridgian Vir-gatopavlovia fittoni Zone) in Dorset (PM, personal observations), Kimmeridge Clay Formation (Pectinatites autissiodorensis to Pectinatites elegans zones) from Dorset (Varney 1984). The taxon is seen regularly in equivalent sediments from the North Sea and adjacent areas (personal observations).