Back
Impletosphaeridium panniforme
From Fensome et al., 2019:
Impletosphaeridium panniforme (Gerlach, 1961, p.196–198, pl.28, fig.13) Morgenroth, 1966a, p.35. Holotype: Gerlach, 1961, pl.28, fig.13. Originally Baltisphaeridium, subsequently (and now) Impletosphaeridium, thirdly Cleistosphaeridium. Eaton et al. (2001, p.191) implied that this species be retained in Impletosphaeridium. Taxonomic senior synonym: Hystrichosphaeridium (now Cleistosphaeridium) placacanthum, according to Sarjeant (1984b, p.86–87) — however, Eaton et al. (2001, p.191) retained Baltisphaeridium (as Impletosphaeridium) panniforme. Age: middle Oligocene.
---------------------------------------------------------------------------------------------------
Original description Gerlach, 1961 [as Baltisphaeridium panniforme]:
Holotype: Pr1170/55 (315)
Paratypes: Pr1170/56 (585) and Pr 1170/57 (624).
Locus typicus: Well Emsbüren 7.
Stratum typicum: Middle Oligocene
Derivation of name: pannus = Lobe, referring to the distal lobe-like processes
Diagnosis:
Central body ellipsoidal to spheroidal, almost entirely without an apical calotte. The upper and lower surfaces, and the edge of theca, are covered with numerous long, slender, massive processes, which are simple or split, often fused flatly with adjacent appendages, and forked distally into several points. The integumentary membrane is delicate and finely reticulated.
Description:
The new species is documented by numerous, well-preserved specimens. The apical pole is split off in a dome-shaped manner, forming a pyloma. Of 30 individuals, only one was found without an opening.
The original shape of the sheaths is ellipsoidal to spheroidal. Due to the detached dome, the theca appears considerably wider than it is tall. The upper and lower surfaces, as well as the margin of the sheaths, are covered with slender, massive appendages, the length of which reaches about two-thirds of the capsule diameter. The formation of these processes is quite bizarre and irregular. Adjacent appendages are often fused together in a flat manner by finely membranous seams. The seams begin at the basal level, or they connect isolated processes above the base. They are not uncommonly perforated in an irregular manner.
At different heights on their stems, the processes branch into several thin branches, which taper distally to a blunt point or appear serrated at the thickened forked ends of their upper margin. Some slender processes form distally lobed ends, which also have a finely serrated edge.
At high magnification, the membrane reveals a fine reticulation. The individual meshes are drawn upwards at certain intervals into two to three fine strands, each of which fuses to form a process.
The new species is restricted to the middle oligocene in the studied swatches. Since it occurs relatively frequently, it can possibly be considered a leading form. Further studies would have to support the limitation of this occurrence.
Affinities:
The development of the appendages is closely related to Cannosphaeropsis aemula Deflandre. However, B. panniforme always lacks the distal connection of the appendages by fine strands.
Dimensions:
Holotype: 94(53:105(63), 22
Paratypes: 74(43:105(59), 29; 72(42):94(53), 22
Maximum: 107(68):105(55), 31
Minimum: 72(51):86(53), 26
Average: (79(50):95(54), 27 (10 measurements)
Impletosphaeridium panniforme (Gerlach, 1961, p.196–198, pl.28, fig.13) Morgenroth, 1966a, p.35. Holotype: Gerlach, 1961, pl.28, fig.13. Originally Baltisphaeridium, subsequently (and now) Impletosphaeridium, thirdly Cleistosphaeridium. Eaton et al. (2001, p.191) implied that this species be retained in Impletosphaeridium. Taxonomic senior synonym: Hystrichosphaeridium (now Cleistosphaeridium) placacanthum, according to Sarjeant (1984b, p.86–87) — however, Eaton et al. (2001, p.191) retained Baltisphaeridium (as Impletosphaeridium) panniforme. Age: middle Oligocene.
---------------------------------------------------------------------------------------------------
Original description Gerlach, 1961 [as Baltisphaeridium panniforme]:
Holotype: Pr1170/55 (315)
Paratypes: Pr1170/56 (585) and Pr 1170/57 (624).
Locus typicus: Well Emsbüren 7.
Stratum typicum: Middle Oligocene
Derivation of name: pannus = Lobe, referring to the distal lobe-like processes
Diagnosis:
Central body ellipsoidal to spheroidal, almost entirely without an apical calotte. The upper and lower surfaces, and the edge of theca, are covered with numerous long, slender, massive processes, which are simple or split, often fused flatly with adjacent appendages, and forked distally into several points. The integumentary membrane is delicate and finely reticulated.
Description:
The new species is documented by numerous, well-preserved specimens. The apical pole is split off in a dome-shaped manner, forming a pyloma. Of 30 individuals, only one was found without an opening.
The original shape of the sheaths is ellipsoidal to spheroidal. Due to the detached dome, the theca appears considerably wider than it is tall. The upper and lower surfaces, as well as the margin of the sheaths, are covered with slender, massive appendages, the length of which reaches about two-thirds of the capsule diameter. The formation of these processes is quite bizarre and irregular. Adjacent appendages are often fused together in a flat manner by finely membranous seams. The seams begin at the basal level, or they connect isolated processes above the base. They are not uncommonly perforated in an irregular manner.
At different heights on their stems, the processes branch into several thin branches, which taper distally to a blunt point or appear serrated at the thickened forked ends of their upper margin. Some slender processes form distally lobed ends, which also have a finely serrated edge.
At high magnification, the membrane reveals a fine reticulation. The individual meshes are drawn upwards at certain intervals into two to three fine strands, each of which fuses to form a process.
The new species is restricted to the middle oligocene in the studied swatches. Since it occurs relatively frequently, it can possibly be considered a leading form. Further studies would have to support the limitation of this occurrence.
Affinities:
The development of the appendages is closely related to Cannosphaeropsis aemula Deflandre. However, B. panniforme always lacks the distal connection of the appendages by fine strands.
Dimensions:
Holotype: 94(53:105(63), 22
Paratypes: 74(43:105(59), 29; 72(42):94(53), 22
Maximum: 107(68):105(55), 31
Minimum: 72(51):86(53), 26
Average: (79(50):95(54), 27 (10 measurements)