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Plethysyrinx
From Williams et al., 2017:
[Plethysyrinx, Sarjeant, 1981, p. 106
Type species: as Cordosphaeridium lemniscatum, Corradini, 1973 (pl.22, fig.5)] ; Plethysyrinx lemniscata, Sarjeant, 1981
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Original description: [Sarjeant, 1981]:
Description:
Cyst spheroidal to broadly ellipsoidal, skolochorate to phragmochorate, trabeculate. Phragma two-layered, with processes typically or constantly formed from the periphragm only. Processes intratabular or in the form of closely interwoven penitabular clusters simulating fenestrate processes; subconical to tubiform, flared or infundibular, with variable distal development. Their walls may be fibrous and the fibres may have rootlike proximal extensions: parasutural features are, however, lacking. Adjacent processes or clusters are connected by a complete or incomplete web-like meshwork of trabeculae, but no external investing membrane is developed.
Paratabulation gonyaulacacean, with the formula 3-4`, 6", 0c, 5-6```, 0-1p, 1````, ?0s. The antapical process may be larger and more conspicuous, the apical processes smaller than the others.
Archaeopyle single-plate precingular (type P): operculum free.
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Stover and Williams, 1987, p. 179:
Affinities:
Plethysyrinx Sarjeant 1981 and Cyclapophysis Benson 1976 possess intratabular to penitabular, fibrous processes with distal trabeculae or a discontinuous membrane connecting the precingular and postcingular processes. In addition, both genera have isolated apical and antapical processes, a precingular archeopyle and lack cingular processes. These similarities, together with the gonyaulacacean paratabulation displayed by Plethysyrinx and Cyclapophysis, attest to their being congeneric.
[Plethysyrinx, Sarjeant, 1981, p. 106
Type species: as Cordosphaeridium lemniscatum, Corradini, 1973 (pl.22, fig.5)] ; Plethysyrinx lemniscata, Sarjeant, 1981
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Sarjeant, 1981]:
Description:
Cyst spheroidal to broadly ellipsoidal, skolochorate to phragmochorate, trabeculate. Phragma two-layered, with processes typically or constantly formed from the periphragm only. Processes intratabular or in the form of closely interwoven penitabular clusters simulating fenestrate processes; subconical to tubiform, flared or infundibular, with variable distal development. Their walls may be fibrous and the fibres may have rootlike proximal extensions: parasutural features are, however, lacking. Adjacent processes or clusters are connected by a complete or incomplete web-like meshwork of trabeculae, but no external investing membrane is developed.
Paratabulation gonyaulacacean, with the formula 3-4`, 6", 0c, 5-6```, 0-1p, 1````, ?0s. The antapical process may be larger and more conspicuous, the apical processes smaller than the others.
Archaeopyle single-plate precingular (type P): operculum free.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Stover and Williams, 1987, p. 179:
Affinities:
Plethysyrinx Sarjeant 1981 and Cyclapophysis Benson 1976 possess intratabular to penitabular, fibrous processes with distal trabeculae or a discontinuous membrane connecting the precingular and postcingular processes. In addition, both genera have isolated apical and antapical processes, a precingular archeopyle and lack cingular processes. These similarities, together with the gonyaulacacean paratabulation displayed by Plethysyrinx and Cyclapophysis, attest to their being congeneric.