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Cyclonephelium eisenackii
Cyclonephelium eisenackii Davey, 1969
Now Pseudoceratium. Originally Cyclonephelium, subsequently Aptea, thirdly (and now) Pseudoceratium.
Tax. jr. synonym of Aptea (now Pseudoceratium) polymorpha Eisenack, 1958, according to Cookson and Eisenack, 1974. Below, 1981, retained Cyclonephelium (as Aptea) eisenackii as a separate species.
Holotype: Davey, 1969, pl.8, figs.3-4; pl.9, fig.4
Locus typicus: Saskatchewan, Canada
Stratum typicum: Albian
Original diagnosis: Davey, 1969, p.170
Shell subtriangular, flattened, with convex sides. Apical horn well developed; antapical horns, if present, very reduced. Greater part of shell surface ornamented by complex network of low crests and short, capitate processes. In centre of both dorsal and ventral sides there is a circular area devoid of ornamentation. Apical archaeopyle always present.
Dimensions: shell length 70-92 µm (4 complete specimens measured); shell length (operculum missing) 55 (63.1) 71 µm, width 66 (72.1) 84 µm, height of crests 2 (4.2) 7 µm.
Original description: Davey, 1969, p.171
The shell surface is ornamented by a very characteristic network of low crests or lamellae which are often broken, so forming isolated processes. A poorly-marked cingulum, outlined by the crests, is occasionally discernible. The apical operculum is often in position.
Now Pseudoceratium. Originally Cyclonephelium, subsequently Aptea, thirdly (and now) Pseudoceratium.
Tax. jr. synonym of Aptea (now Pseudoceratium) polymorpha Eisenack, 1958, according to Cookson and Eisenack, 1974. Below, 1981, retained Cyclonephelium (as Aptea) eisenackii as a separate species.
Holotype: Davey, 1969, pl.8, figs.3-4; pl.9, fig.4
Locus typicus: Saskatchewan, Canada
Stratum typicum: Albian
Original diagnosis: Davey, 1969, p.170
Shell subtriangular, flattened, with convex sides. Apical horn well developed; antapical horns, if present, very reduced. Greater part of shell surface ornamented by complex network of low crests and short, capitate processes. In centre of both dorsal and ventral sides there is a circular area devoid of ornamentation. Apical archaeopyle always present.
Dimensions: shell length 70-92 µm (4 complete specimens measured); shell length (operculum missing) 55 (63.1) 71 µm, width 66 (72.1) 84 µm, height of crests 2 (4.2) 7 µm.
Original description: Davey, 1969, p.171
The shell surface is ornamented by a very characteristic network of low crests or lamellae which are often broken, so forming isolated processes. A poorly-marked cingulum, outlined by the crests, is occasionally discernible. The apical operculum is often in position.