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Polystephanephorus
From Williams et al., 2017:
[Polystephanephorus, Sarjeant, 1961b, p. 1096; Emendation: Stancliffe and Sarjeant, 1990, p. 205.
Tax. sr. syn.: Hystrichosphaerina, according to Duxbury (1980, p.125–126) — however, Lentin and Williams (1981, p.232) and Davey (1982b, p.20) retained Polystephanephorus; Systematophora, according to Brenner (1988, p.83) — however, Stancliffe and Sarjeant (1990, p.205) retained Polystephanephorus.
Type species: Polystephanosphaera calatha, Sarjeant, 1961a (pl.14, fig.7; text-fig.7)]; Sarjeant, 1961b; emend. Stancliffe and Sarjeant, 1990
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Original description: [Sarjeant, 1961]:
Description:
Hystrichospheres bearing processes solid or hollow and closed distally, whose points of origin are arranged in circles or polygons, the groups of processes thus formed being arranged in a set pattern or at constant intervals over the shell surface. The processes of each group are connected together at their tips by a trabecula in the form of a ring, typically formed by the bifurcation of one process and the extension of its branches, parallel to the shell surface, to meet at right-angles the tips of the other processes of the group; each cluster thus has the appearance of an open-walled and open-ended tube. Individual processes may show linkage to adjacent processes by basal extensions or by the development of connecting trabeculae at positions along their length.
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Emended description:
Stancliffe and Sarjeant, 1990:
Diagnosis:
Central body spherical lo subspherical: phragma single layered (or apparently so), with a smooth to granulated surface.
Paratabulation reflected by intratabular process clusters or single processes, giving a formula of ?4`, 5", x or 5c, 6```, 1````, x or 4s.
Process clusters are developed on the major paraplates; processes forming the clusters are thin and solid with smooth to granular walls. Branching can occur medially along the process length or distally, with up to two orders of branching, though this is not common. Approximately five to nine processes form each ring cluster; these are connected distally by a trabecula arising from the bifurcation of one of the processes, Process clusters may or may not be interconnected by trabeculae, When cingular or sulcal processes are developed, they are isolated, solid, small and thin with a brief distal bifurcation.
Archaeopyle apical, typr (tA), with a distinct sulcal notch and free operculum.
Affinities:
The genus differs from Systematophora in that Polystephanophorus has ring-trabeculae and inter process-cluster trabeculae. Taeniophora and Rigaudella exhibit transcingular structures; these are not developed on Polystephanophorus. Emmetrocysta and Hystrichsphaerina have a paratabulation formula which includes six precingular paraplates, while Polystephanophorus has only five. The process clusters with many processes developed by Polystephanophorus are not formed by Rigaudella.
[Polystephanephorus, Sarjeant, 1961b, p. 1096; Emendation: Stancliffe and Sarjeant, 1990, p. 205.
Tax. sr. syn.: Hystrichosphaerina, according to Duxbury (1980, p.125–126) — however, Lentin and Williams (1981, p.232) and Davey (1982b, p.20) retained Polystephanephorus; Systematophora, according to Brenner (1988, p.83) — however, Stancliffe and Sarjeant (1990, p.205) retained Polystephanephorus.
Type species: Polystephanosphaera calatha, Sarjeant, 1961a (pl.14, fig.7; text-fig.7)]; Sarjeant, 1961b; emend. Stancliffe and Sarjeant, 1990
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Sarjeant, 1961]:
Description:
Hystrichospheres bearing processes solid or hollow and closed distally, whose points of origin are arranged in circles or polygons, the groups of processes thus formed being arranged in a set pattern or at constant intervals over the shell surface. The processes of each group are connected together at their tips by a trabecula in the form of a ring, typically formed by the bifurcation of one process and the extension of its branches, parallel to the shell surface, to meet at right-angles the tips of the other processes of the group; each cluster thus has the appearance of an open-walled and open-ended tube. Individual processes may show linkage to adjacent processes by basal extensions or by the development of connecting trabeculae at positions along their length.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Stancliffe and Sarjeant, 1990:
Diagnosis:
Central body spherical lo subspherical: phragma single layered (or apparently so), with a smooth to granulated surface.
Paratabulation reflected by intratabular process clusters or single processes, giving a formula of ?4`, 5", x or 5c, 6```, 1````, x or 4s.
Process clusters are developed on the major paraplates; processes forming the clusters are thin and solid with smooth to granular walls. Branching can occur medially along the process length or distally, with up to two orders of branching, though this is not common. Approximately five to nine processes form each ring cluster; these are connected distally by a trabecula arising from the bifurcation of one of the processes, Process clusters may or may not be interconnected by trabeculae, When cingular or sulcal processes are developed, they are isolated, solid, small and thin with a brief distal bifurcation.
Archaeopyle apical, typr (tA), with a distinct sulcal notch and free operculum.
Affinities:
The genus differs from Systematophora in that Polystephanophorus has ring-trabeculae and inter process-cluster trabeculae. Taeniophora and Rigaudella exhibit transcingular structures; these are not developed on Polystephanophorus. Emmetrocysta and Hystrichsphaerina have a paratabulation formula which includes six precingular paraplates, while Polystephanophorus has only five. The process clusters with many processes developed by Polystephanophorus are not formed by Rigaudella.