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Hystrichosphaeridium recurvatum ssp. parvum
From Fensome et al., 2019:
Hystrichosphaeridium recurvatum ssp. parvum (Rozen, 1965, p.303–304, pl.4, fig.6; text-fig.13) Lentin and Williams, 1973, p.79. Holotype: Rozen, 1965, pl.4, fig.6; text-fig.13. Originally Hystrichosphaeridium recurvatum var. parvum,
subsequently (and now) Hystrichosphaeridium recurvatum subsp. parvum, thirdly Hystrichosphaeridium palmatum subsp. parvum (combination illegitimate), fourthly Hystrichosphaeridium duplum subsp. parvum (combination illegitimate). Age: Late Eocene.
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Original description: [Rozen, 1965] (translated from French):
Hystrichosphaeridium recurvatum (WHITE, 1842) parvum n. var.
(PI. IV, fig. 6; text, fig. 13.)
Type origin. - Oedelem Quarry (Bartonian), preparation nº 1200.
Remarks. - Organism with a smooth, spherical shell surrounded by a relatively thin membrane and bristling with hollow processes that do not communicate with the interior. They arise from slight depressions, probably secondary to the shell, and have a base, broadened into a cushion, which narrows rather abruptly. The processes reach a length of 1/3 to 1/2 the shell diameter and terminate in ramifications arranged like umbrella ribs, most often curved towards the shell; their length exceeds 1/2 the length of the processes. It was the structure of the processes that led me to identify this species with that of H. H. White and M. Lejeune-Carpentier. However, the illustrated specimen is smaller than the holotype, with fewer and relatively short processes. The shell ornamentation is also absent. It therefore seems preferable to consider this specimen from Oedelem as a new variety of Hystrichosphaeridium recurvatum characterized by the absence of strongly marked pads at the base of the processes, reduced dimensions, and terminal process branches that are very long compared to the processes themselves. It differs from the previous one by a membrane that is still thin, but relatively thicker.
Dimensions.
Diameter of the central body: 27-28 μm; length of processes: 11-13 μm; thickness of processes: 4 μm at the base; thickness of the membrane: approximately 1 μm; number of processes: approximately 14.
Material observed. - 1 copy.
Hystrichosphaeridium recurvatum ssp. parvum (Rozen, 1965, p.303–304, pl.4, fig.6; text-fig.13) Lentin and Williams, 1973, p.79. Holotype: Rozen, 1965, pl.4, fig.6; text-fig.13. Originally Hystrichosphaeridium recurvatum var. parvum,
subsequently (and now) Hystrichosphaeridium recurvatum subsp. parvum, thirdly Hystrichosphaeridium palmatum subsp. parvum (combination illegitimate), fourthly Hystrichosphaeridium duplum subsp. parvum (combination illegitimate). Age: Late Eocene.
---------------------------------------------------------------------------------------------------
Original description: [Rozen, 1965] (translated from French):
Hystrichosphaeridium recurvatum (WHITE, 1842) parvum n. var.
(PI. IV, fig. 6; text, fig. 13.)
Type origin. - Oedelem Quarry (Bartonian), preparation nº 1200.
Remarks. - Organism with a smooth, spherical shell surrounded by a relatively thin membrane and bristling with hollow processes that do not communicate with the interior. They arise from slight depressions, probably secondary to the shell, and have a base, broadened into a cushion, which narrows rather abruptly. The processes reach a length of 1/3 to 1/2 the shell diameter and terminate in ramifications arranged like umbrella ribs, most often curved towards the shell; their length exceeds 1/2 the length of the processes. It was the structure of the processes that led me to identify this species with that of H. H. White and M. Lejeune-Carpentier. However, the illustrated specimen is smaller than the holotype, with fewer and relatively short processes. The shell ornamentation is also absent. It therefore seems preferable to consider this specimen from Oedelem as a new variety of Hystrichosphaeridium recurvatum characterized by the absence of strongly marked pads at the base of the processes, reduced dimensions, and terminal process branches that are very long compared to the processes themselves. It differs from the previous one by a membrane that is still thin, but relatively thicker.
Dimensions.
Diameter of the central body: 27-28 μm; length of processes: 11-13 μm; thickness of processes: 4 μm at the base; thickness of the membrane: approximately 1 μm; number of processes: approximately 14.
Material observed. - 1 copy.