Back
Polysphaeridium biformum
Polysphaeridium biformum Islam, 1983
Holotype: Islam 1983, pl.4, fig.6
Paratype: Islam, 1983
Locus typicus: Hampshire Basin, S England
Stratum typicum: Middle Eocene
Original diagnosis: Islam, 1983, p. 342
Cyst subspherical to ellipsoidal, skolochorate and biphragmal; periphragm chagrinate; numerous nontabular processes of two distinct types: tubular with wider ends and distally open, which are similar to those of P. subtile, and solid, which are proximally thicker and distally entire, bifurcate or with wider fenestrate ramifications, latter type preferably placed in paracingular areas or elsewhere; some transitional types proximally hollow while solid in remaining length; solid and partly solid processes longer than tubular ones; archeopyle epicystal type (tAtP), most specimens split.
Dimensions: Holotype: cyst body 52 x 42 µm, length of processes 11-19 µm. Range: maximum median cyst diameter 47(45)42 µm, length of processes 10-20 µm. Specimens measured: 10.
Affinities:
Islam, 1983, p. 343: This species differs from others of the genus in possessing two types of processes, the length of the longer ones approaching half the median diameter of the cyst. It is related to P. subble through intermediate and transitional forms found in the same preparations.
Holotype: Islam 1983, pl.4, fig.6
Paratype: Islam, 1983
Locus typicus: Hampshire Basin, S England
Stratum typicum: Middle Eocene
Original diagnosis: Islam, 1983, p. 342
Cyst subspherical to ellipsoidal, skolochorate and biphragmal; periphragm chagrinate; numerous nontabular processes of two distinct types: tubular with wider ends and distally open, which are similar to those of P. subtile, and solid, which are proximally thicker and distally entire, bifurcate or with wider fenestrate ramifications, latter type preferably placed in paracingular areas or elsewhere; some transitional types proximally hollow while solid in remaining length; solid and partly solid processes longer than tubular ones; archeopyle epicystal type (tAtP), most specimens split.
Dimensions: Holotype: cyst body 52 x 42 µm, length of processes 11-19 µm. Range: maximum median cyst diameter 47(45)42 µm, length of processes 10-20 µm. Specimens measured: 10.
Affinities:
Islam, 1983, p. 343: This species differs from others of the genus in possessing two types of processes, the length of the longer ones approaching half the median diameter of the cyst. It is related to P. subble through intermediate and transitional forms found in the same preparations.