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Pyxidinopsis granulata
Pyxidiniopsis granulata (Ioannides et al., 1977) Lentin and Williams, 1985
Originally Tapeinosphaeridium, subsequently Tectatodinium?, thirdly (and now) Pyxidinopsis.
Holotype: Ioannides et al., 1977, pl.4, fig.18
Locus typicus: Clavell"s Hard, Dorset, England
Stratum typicum: Kimmeridgian
Original diagnosis: Ioannides et al., 1977, p. 462: Tapeinosphaeridium granulatum
Shell spherical to ovoidal, thin-walled; surface finely to coarsely granular. Sutures may be weakly marked giving possible indication of tabulation but not determined. Cingulum sometimes poorly suggested; sulcus not observed. A precingular archaeopyle infrequently present.
Original description: Ioannides et al., 1977, p. 462: Tapeinosphaeridium granulatum
Shell surface covered with dense grana but without any form of projections. Occasionally, extremely faint sutures may simulate a plate pattern but tabulation is never determined. Cingulum may sometimes be poorly indicated by reduction of grana or arrangement of folds along a median zone. A polygonal to subcircular precingular archaeopyle is infrequently formed by loss of one plate. Secondary folds running on or parallel to periphery always present.
Dimensions. Range: shell length 48-73 µm; breadth 46-72 µm (15 specimens measured).
Affinities:
Ioannides et al., 1977, p. 462: Tapeinosphaeridium granulatum
Tapeinosphaeridium granulatum differs from T. pericompsum loannides, Stavrinos, and Downie, in the presence of grana. Chytroeisphaeridia pocockii Sarjeant, 1968, has an apical archaeopyle. Operculodinium psilatum Wall, 1967, and Tectatodinium pellitum Wall, 1967, possess two-layered shell walls, and the former is also ornamented with spiny processes.
Originally Tapeinosphaeridium, subsequently Tectatodinium?, thirdly (and now) Pyxidinopsis.
Holotype: Ioannides et al., 1977, pl.4, fig.18
Locus typicus: Clavell"s Hard, Dorset, England
Stratum typicum: Kimmeridgian
Original diagnosis: Ioannides et al., 1977, p. 462: Tapeinosphaeridium granulatum
Shell spherical to ovoidal, thin-walled; surface finely to coarsely granular. Sutures may be weakly marked giving possible indication of tabulation but not determined. Cingulum sometimes poorly suggested; sulcus not observed. A precingular archaeopyle infrequently present.
Original description: Ioannides et al., 1977, p. 462: Tapeinosphaeridium granulatum
Shell surface covered with dense grana but without any form of projections. Occasionally, extremely faint sutures may simulate a plate pattern but tabulation is never determined. Cingulum may sometimes be poorly indicated by reduction of grana or arrangement of folds along a median zone. A polygonal to subcircular precingular archaeopyle is infrequently formed by loss of one plate. Secondary folds running on or parallel to periphery always present.
Dimensions. Range: shell length 48-73 µm; breadth 46-72 µm (15 specimens measured).
Affinities:
Ioannides et al., 1977, p. 462: Tapeinosphaeridium granulatum
Tapeinosphaeridium granulatum differs from T. pericompsum loannides, Stavrinos, and Downie, in the presence of grana. Chytroeisphaeridia pocockii Sarjeant, 1968, has an apical archaeopyle. Operculodinium psilatum Wall, 1967, and Tectatodinium pellitum Wall, 1967, possess two-layered shell walls, and the former is also ornamented with spiny processes.