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Polystephanosphaera paracalathus
Polystephanosphaera paracalathus Sarjeant, 1960; Emendation: Stancliffe and Sarjeant, 1990, p.206, as Polystephanephorus paracalathus.
Now Polystephanephorus. Originally Polystephanosphaera, subsequently (and now) Polystephanephorus, thirdly Hystrichosphaerina.
Holotype: Sarjeant 1960, pl.6, fig.4; text-fig.3b; Stancliffe and Sarjeant, 1990, pl.2, figs.2,3,5; text-fig.2
Locus typicus: Webb, Major and Company"s Crook Hill brickyard, 2 mile south of Chickerell Church, near Weymouth (grid reference 800646).
Stratum typicum: Middle Callovian
Original diagnosis: Sarjeant, 1960, p. 143
A species of Polystephanosphaera having processes of variable thickness, sometimes bifurcating, sometimes simple, most often widening considerably at a constant distance from the shell surfacc. All proccsses of each group bend outwards from their point of origin and are comlected together at their tips by a trabecula, each group of processes thus having thc aipect of a skeletal vase with a bell mouth.
Original description: Sarjeant, 1960, p. 143
As in P. calatus, the trabecula linking each group of processes at their tips appears to arise from the bifurcation of a single process in each group and the lateral extension of its branches to link up with the tips of other processes.
In some cases, adjacent groups of processes are connected by a single trabecula: these linking trabeculae have, hanging from them at about mid-point between process groups, a membraneous filament.
Dimensions. Type: overall diameter 92 µm, diameter of shell 40 µm, processes 26 µm in length. Range: overall diameter 85 to 100 µm.
Affinities:
Sarjeant, 1960, p. 143-144: In the arrangement of processes and their linkage, this species differs from all the other described species and resembles Polystephanospllacra ealathlls, of the Oxford Clay of Yorkshire (1960). However, the more robust form of the processes and their broadening at the point of linkage, and the bell-mouthed form of the process groups afford major differences from the species. The processes of Polystephanosphaera urnaformis (Cookson, 1953) differ in that they are coalescent at their base as well as at their tip.
Now Polystephanephorus. Originally Polystephanosphaera, subsequently (and now) Polystephanephorus, thirdly Hystrichosphaerina.
Holotype: Sarjeant 1960, pl.6, fig.4; text-fig.3b; Stancliffe and Sarjeant, 1990, pl.2, figs.2,3,5; text-fig.2
Locus typicus: Webb, Major and Company"s Crook Hill brickyard, 2 mile south of Chickerell Church, near Weymouth (grid reference 800646).
Stratum typicum: Middle Callovian
Original diagnosis: Sarjeant, 1960, p. 143
A species of Polystephanosphaera having processes of variable thickness, sometimes bifurcating, sometimes simple, most often widening considerably at a constant distance from the shell surfacc. All proccsses of each group bend outwards from their point of origin and are comlected together at their tips by a trabecula, each group of processes thus having thc aipect of a skeletal vase with a bell mouth.
Original description: Sarjeant, 1960, p. 143
As in P. calatus, the trabecula linking each group of processes at their tips appears to arise from the bifurcation of a single process in each group and the lateral extension of its branches to link up with the tips of other processes.
In some cases, adjacent groups of processes are connected by a single trabecula: these linking trabeculae have, hanging from them at about mid-point between process groups, a membraneous filament.
Dimensions. Type: overall diameter 92 µm, diameter of shell 40 µm, processes 26 µm in length. Range: overall diameter 85 to 100 µm.
Affinities:
Sarjeant, 1960, p. 143-144: In the arrangement of processes and their linkage, this species differs from all the other described species and resembles Polystephanospllacra ealathlls, of the Oxford Clay of Yorkshire (1960). However, the more robust form of the processes and their broadening at the point of linkage, and the bell-mouthed form of the process groups afford major differences from the species. The processes of Polystephanosphaera urnaformis (Cookson, 1953) differ in that they are coalescent at their base as well as at their tip.