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Jansonia scarffei
Jansonia scarffeii Tykoezinski et al., 2001, p.84,86, pl.1, figs.1a-c,2a-c,3a-b,4a-c,5a-c; pl.4, figs.10-13.
NOW Fostericysta. Originally Jansonia, subsequently (and now) Fostericysta.
Holotype: Tykoezinski et al., 2001, pl.1, figs.1a-c.
Age: Late Bathonian.
Original description (Tykoezinski et al., 2001):
Jansonia scarffei sp. nov. Plate 1, figs. 1-5; Plate 4, figs. 10-13
Microdinium? sp. B, Tykoezinski, (written commun., 1982), p. 67, pi. 11, figs. 1-2
Derivation of Name. Proposed in honour of J. Howard Scarffe, Professor of Oncology at The Christie Hospital, Manchester, Wellcome Trust, London.
Type Locality. Shipton-on-Cherwell Cement Works Quarry, Oxfordshire (GR 477175).
Type Horizon. Abbotsbury Cornbrash Formation, Berry member. Late Bathonian, C. discus Zone, C. discus Subzone.
Holotype. Slide SLC2/1, reference SI3/4 (Plate 1, figures la-c).
Diagnosis. A tabulate species of Jansonia characterized by prominent, distally denticulate to flutedparasutural crests. The cyst has a distinctive trapezoid ambitus with a strongly indented paracingulum. The paracingulum is proportionally wide for the length of the cyst and is moderately to weakly laevorotatory. The parasulcus is prominent on the ventral surface of the cyst with a large omegaform ps paraplate. The cyst has an apical archeopyle with the general formula (acp, tA, tl?). The operculum is free. The paratabulation formula as far as can be established from the observed specimens is acp?, X1 , Xa, 7", 7c, as, Xs, ps, fm, lp, 6'", 1"". The cyst is also characteristically dark in color.
Description. Shape: The cyst is strongly dorsoventrally compressed. The ambitus in most specimens is approximately trapezoid; the paracingulum is moderately to strongly indented. The hypocyst is oblate, and larger than the epicyst.
Wall relationships: The cyst is proximate and acavate, with an autophragm composed of an inner pedium and outer dense luxurium, in the terminology of Below 1987a,b.
Wall features: The cyst wall has a rugulate to sparsely granulate surface. The luxurium expands at the parasutures to form densely structured, distally denticulate, rarely perforate parasutural septa which are most strongly developed in the interprecingular and interpostcingular positions. The denticules are 1.5-2 (am high and 1-2 um wide, distally blunt. The autophragm is frequently dark in colour.
Paratabulation and parasutural features: The paracingulum is wide, representing 20% to 25% of the cyst length. It is moderately to weakly laevoratatory, displaced by half its width or less. The parasulcus is preferentially developed on the hypocyst. The ps paraplate is large, omegaform and bulges into 1"". The paratabulation formula is acp?, X', Xa, 7", 7c, as, Xs, ps, fm, lp, 6'", 1"". The cyst shows a partiform hypocystal pattern, with a large 1'" displacing lp towards the antapex. Archeopyle: The archeopyle comprises the acp, apical and probably the anterior intercalary paraplates. The operculum is free, with the general formula (acp, tA, tl?). Cyst Size: Length min. 19(21)25 µm max. (Holotype 25 µm). Width min. 18(21)27 (µm max. (Holotype 27 µm). Ten specimens measured, excluding parasutural ornament.
Remarks and Comparisons. Jansonia scarffei sp. nov. differs from J. jurassica Pocock 1972 emend. Jansonius 1986, and J. manifesta Riding et al., 1991 in having more prominent, distally denticulate to fluted parasutural crests and a distinctive trapezoid ambitus indented at the paracingulum. In all specimens observed the archeopyle has functioned, however no separate operculum has been observed.
Occurrence. Middle to Late Bathonian, T. subcontractus?/M. morrisi to C. discus Zones, White Limestone Formation, Shipton Member to Abbotsbury Cornbrash Formation, Berry Member, Shipton-on-Cherwell, Oxfordshire.
NOW Fostericysta. Originally Jansonia, subsequently (and now) Fostericysta.
Holotype: Tykoezinski et al., 2001, pl.1, figs.1a-c.
Age: Late Bathonian.
Original description (Tykoezinski et al., 2001):
Jansonia scarffei sp. nov. Plate 1, figs. 1-5; Plate 4, figs. 10-13
Microdinium? sp. B, Tykoezinski, (written commun., 1982), p. 67, pi. 11, figs. 1-2
Derivation of Name. Proposed in honour of J. Howard Scarffe, Professor of Oncology at The Christie Hospital, Manchester, Wellcome Trust, London.
Type Locality. Shipton-on-Cherwell Cement Works Quarry, Oxfordshire (GR 477175).
Type Horizon. Abbotsbury Cornbrash Formation, Berry member. Late Bathonian, C. discus Zone, C. discus Subzone.
Holotype. Slide SLC2/1, reference SI3/4 (Plate 1, figures la-c).
Diagnosis. A tabulate species of Jansonia characterized by prominent, distally denticulate to flutedparasutural crests. The cyst has a distinctive trapezoid ambitus with a strongly indented paracingulum. The paracingulum is proportionally wide for the length of the cyst and is moderately to weakly laevorotatory. The parasulcus is prominent on the ventral surface of the cyst with a large omegaform ps paraplate. The cyst has an apical archeopyle with the general formula (acp, tA, tl?). The operculum is free. The paratabulation formula as far as can be established from the observed specimens is acp?, X1 , Xa, 7", 7c, as, Xs, ps, fm, lp, 6'", 1"". The cyst is also characteristically dark in color.
Description. Shape: The cyst is strongly dorsoventrally compressed. The ambitus in most specimens is approximately trapezoid; the paracingulum is moderately to strongly indented. The hypocyst is oblate, and larger than the epicyst.
Wall relationships: The cyst is proximate and acavate, with an autophragm composed of an inner pedium and outer dense luxurium, in the terminology of Below 1987a,b.
Wall features: The cyst wall has a rugulate to sparsely granulate surface. The luxurium expands at the parasutures to form densely structured, distally denticulate, rarely perforate parasutural septa which are most strongly developed in the interprecingular and interpostcingular positions. The denticules are 1.5-2 (am high and 1-2 um wide, distally blunt. The autophragm is frequently dark in colour.
Paratabulation and parasutural features: The paracingulum is wide, representing 20% to 25% of the cyst length. It is moderately to weakly laevoratatory, displaced by half its width or less. The parasulcus is preferentially developed on the hypocyst. The ps paraplate is large, omegaform and bulges into 1"". The paratabulation formula is acp?, X', Xa, 7", 7c, as, Xs, ps, fm, lp, 6'", 1"". The cyst shows a partiform hypocystal pattern, with a large 1'" displacing lp towards the antapex. Archeopyle: The archeopyle comprises the acp, apical and probably the anterior intercalary paraplates. The operculum is free, with the general formula (acp, tA, tl?). Cyst Size: Length min. 19(21)25 µm max. (Holotype 25 µm). Width min. 18(21)27 (µm max. (Holotype 27 µm). Ten specimens measured, excluding parasutural ornament.
Remarks and Comparisons. Jansonia scarffei sp. nov. differs from J. jurassica Pocock 1972 emend. Jansonius 1986, and J. manifesta Riding et al., 1991 in having more prominent, distally denticulate to fluted parasutural crests and a distinctive trapezoid ambitus indented at the paracingulum. In all specimens observed the archeopyle has functioned, however no separate operculum has been observed.
Occurrence. Middle to Late Bathonian, T. subcontractus?/M. morrisi to C. discus Zones, White Limestone Formation, Shipton Member to Abbotsbury Cornbrash Formation, Berry Member, Shipton-on-Cherwell, Oxfordshire.