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Oligosphaeridium tuberculatum
From Fensome et al., 2019:
Dolby, 2019, VRp.5, pl.1, figs.13–17. Holotype: Dolby, 2019, pl.1, fig.13. Taxonomic junior synonym Bourkidinium? michoudii (name not validly published), according to Dolby (2019, VRp.5). Age: Aptian - early Albian.
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Synonymy. Bourkidinium? ‘michoudii’ Dolby et al. 2013, pl. 1, fig. 9.
Holotype. Plate 1, figure 13.
Type locality. ConocoPhillips Newby 1AA/03-12-81-6W4, Alberta, 222.06 m, upper McMurray Formation.
Repository. National Collection of Type Invertebrate and Plant Fossils, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, under curation number GSC 139228. Diagnosis. A species of Oligosphaeridium in which the body surface is coarsely granulose to verrucose and the processes are finely granulose terminating in expanded, finely serrate margins without deep indentations.
Description. Shape: The central body is sphaeroidal to slightly ellipsoidal although usually markedly distorted due to preservational rigours. The periphragm and endophragm are closely appressed except where the periphragm forms intratabular, plate-centred processes. The processes are cylindrical to slightly flared, open distally with expanded, finely serrate margins without deep indentations. The surface of the processes is finely granulose, sometimes with longitudinal wrinkles. There are occasional ellipsoidal holes, aligned longitudinally, near the distal ends of the processes.
Tabulation: Indicated only by archaeopyle and accessory archaeopyle sutures between precingular plates. Some specimens show alignment of grana/verrucae in the post-cingular/ antapical regions that reflect a gonyaulacacean tabulation.
Archaeopyle: Apical; operculum, free.
Cingulum: Often not apparent but indicated on some specimens by intermittent lines of grana and absence of processes.
Body surface: Coarsely granulose to verrucose with elements up to 2 mm in diameter.
Distribution of sculptural elements: 40, 600, 6000, 10000.
Dimensions [min (mode) max].
Body diameter: 32 (45) 57 mm (20 specimens).
Holotype: 53 mm.
Processes: 14–37 mm long, 4–10 mm diameter. Tips: 14–30 mm diameter.
Derivation of name. Named for the distinctive coarsely granulose to verrucose surface ornament.
Comparison. Oligosphaeridium tuberculatum sp. nov. is distinguished from Oligosphaeridium totum, which is a significantly more robust species, by the coarsely granulose to verrucose surface ornament and granulose processes. Oligosphaeridium verrucosum is larger and more robust and has smooth processes with more complex terminations. Kaiwaradinium buccinatum and Kaiwaradinium scrutillinum are granular but their bodies are elongate-ellipsoidal and are more robust.
Occurrence. Aptian to early Albian, middle and upper McMurray Formation and Clearwater Formation.
Dolby, 2019, VRp.5, pl.1, figs.13–17. Holotype: Dolby, 2019, pl.1, fig.13. Taxonomic junior synonym Bourkidinium? michoudii (name not validly published), according to Dolby (2019, VRp.5). Age: Aptian - early Albian.
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Synonymy. Bourkidinium? ‘michoudii’ Dolby et al. 2013, pl. 1, fig. 9.
Holotype. Plate 1, figure 13.
Type locality. ConocoPhillips Newby 1AA/03-12-81-6W4, Alberta, 222.06 m, upper McMurray Formation.
Repository. National Collection of Type Invertebrate and Plant Fossils, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, under curation number GSC 139228. Diagnosis. A species of Oligosphaeridium in which the body surface is coarsely granulose to verrucose and the processes are finely granulose terminating in expanded, finely serrate margins without deep indentations.
Description. Shape: The central body is sphaeroidal to slightly ellipsoidal although usually markedly distorted due to preservational rigours. The periphragm and endophragm are closely appressed except where the periphragm forms intratabular, plate-centred processes. The processes are cylindrical to slightly flared, open distally with expanded, finely serrate margins without deep indentations. The surface of the processes is finely granulose, sometimes with longitudinal wrinkles. There are occasional ellipsoidal holes, aligned longitudinally, near the distal ends of the processes.
Tabulation: Indicated only by archaeopyle and accessory archaeopyle sutures between precingular plates. Some specimens show alignment of grana/verrucae in the post-cingular/ antapical regions that reflect a gonyaulacacean tabulation.
Archaeopyle: Apical; operculum, free.
Cingulum: Often not apparent but indicated on some specimens by intermittent lines of grana and absence of processes.
Body surface: Coarsely granulose to verrucose with elements up to 2 mm in diameter.
Distribution of sculptural elements: 40, 600, 6000, 10000.
Dimensions [min (mode) max].
Body diameter: 32 (45) 57 mm (20 specimens).
Holotype: 53 mm.
Processes: 14–37 mm long, 4–10 mm diameter. Tips: 14–30 mm diameter.
Derivation of name. Named for the distinctive coarsely granulose to verrucose surface ornament.
Comparison. Oligosphaeridium tuberculatum sp. nov. is distinguished from Oligosphaeridium totum, which is a significantly more robust species, by the coarsely granulose to verrucose surface ornament and granulose processes. Oligosphaeridium verrucosum is larger and more robust and has smooth processes with more complex terminations. Kaiwaradinium buccinatum and Kaiwaradinium scrutillinum are granular but their bodies are elongate-ellipsoidal and are more robust.
Occurrence. Aptian to early Albian, middle and upper McMurray Formation and Clearwater Formation.