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Polysphaeridium williamsii
Polysphaeridium williamsii Boltenhagen, 1977
NOW Impletosphaeridium. Originally Polysphaeridium, subsequently Cleistosphaeridium?, thirdly (and now) Impletosphaeridium.
Holotype: Boltenhagen, 1977, pl.2, fig.6
Age: Cenomanian-Early Turonian
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Original description as Polysphaeridium williamsii: [Boltenhagen, 1977, p. 41] (translated from French):
DIAGNOSIS
Subspherical or ovoid shell covered by numerous cylindrical-conical filiform appendages, whose ends are pointed, bifid, or flared. Apical archaeopyle.
DESCRIPTION
Our subspherical or ovoid specimens, with a smooth, extremely thin membrane, are characterized by numerous filiform appendages (+/- 80). These are cylindrical-conical and can be classified into four types: pointed, bifid, flared, or simply ending in a circular orifice. All appendages have broad bases and are isolated from the interior of the shell by the endophragm. The spacing of the appendages, uniformly distributed, is approximately equal to half their length.
The apical archaeopyle has a polygonal outline.
OBSERVATIONS
This species is common, but due to the fragility of its membrane and appendages, well-preserved specimens are very rare.
DIMENSIONS
Holotype: cyst with appendages d' = 56 x 52 μ
without appendages d'' = 38 x 37 μ
appendages L = 7 à 8 μ
Paratype: cyst with appendages d' = 39 x 38 μ
without appendages d'' = 28 x 27 μ
appendages L = 6 à 7 μ
According to 3 other specimens:
cyst with appendages d' = 48 x 43 μ; 44 x 37 μ; 48 x 47 μ
without appendages d'' = 38 x 35 μ; 32 x 26 μ; 35 x 33 μ
appendages L = 6, 7, 8 μ
COMPARISON
The specimens considered bear many resemblances to Hystrichosphaeridium (Xanthidium) simplex
(White, 1842), described and represented by E. Gerlach (1961, p. 190, P1. 28, Fig. 10). However, it has appendages that all end in a slightly flared orifice, while the tips of the appendages of the Gabonese species are of diverse shapes.
Stratigraphic and geographic position
Upper Cretaceous: Cenomanian - Lower Turonian; Gabon (Libreville)
NOW Impletosphaeridium. Originally Polysphaeridium, subsequently Cleistosphaeridium?, thirdly (and now) Impletosphaeridium.
Holotype: Boltenhagen, 1977, pl.2, fig.6
Age: Cenomanian-Early Turonian
--------------------------------------------------------------------------------------------------------------------------------------------
Original description as Polysphaeridium williamsii: [Boltenhagen, 1977, p. 41] (translated from French):
DIAGNOSIS
Subspherical or ovoid shell covered by numerous cylindrical-conical filiform appendages, whose ends are pointed, bifid, or flared. Apical archaeopyle.
DESCRIPTION
Our subspherical or ovoid specimens, with a smooth, extremely thin membrane, are characterized by numerous filiform appendages (+/- 80). These are cylindrical-conical and can be classified into four types: pointed, bifid, flared, or simply ending in a circular orifice. All appendages have broad bases and are isolated from the interior of the shell by the endophragm. The spacing of the appendages, uniformly distributed, is approximately equal to half their length.
The apical archaeopyle has a polygonal outline.
OBSERVATIONS
This species is common, but due to the fragility of its membrane and appendages, well-preserved specimens are very rare.
DIMENSIONS
Holotype: cyst with appendages d' = 56 x 52 μ
without appendages d'' = 38 x 37 μ
appendages L = 7 à 8 μ
Paratype: cyst with appendages d' = 39 x 38 μ
without appendages d'' = 28 x 27 μ
appendages L = 6 à 7 μ
According to 3 other specimens:
cyst with appendages d' = 48 x 43 μ; 44 x 37 μ; 48 x 47 μ
without appendages d'' = 38 x 35 μ; 32 x 26 μ; 35 x 33 μ
appendages L = 6, 7, 8 μ
COMPARISON
The specimens considered bear many resemblances to Hystrichosphaeridium (Xanthidium) simplex
(White, 1842), described and represented by E. Gerlach (1961, p. 190, P1. 28, Fig. 10). However, it has appendages that all end in a slightly flared orifice, while the tips of the appendages of the Gabonese species are of diverse shapes.
Stratigraphic and geographic position
Upper Cretaceous: Cenomanian - Lower Turonian; Gabon (Libreville)