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Hystrichosphaeropsis minimum
Hystrichosphaeropsis minimum Zevenboom and Santarelli in Zevenboom, 1995, p.144, pl.5, figs.5,7,9.
Name not validly published: considered a manuscript name.
Holotype: Zevenboom, 1995, pl.5, figs.5,7,9.
Age: latest Late Oligocene-Early Miocene.
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Original description (Zevenboom, 1995)
Hystrichosphaeropsis minimus Zevenboom and Santarelli sp.nov. (manuscript name) (Plate V, 3, 6, 9)
?1972 Triblastula cf. sp. T. Borussica (Eisenack, 1954) Morgenroth, 1966; Benedek, p. 24; plate 3, fig. 13
1986a Hystrichosphaeropsis obscura (Habib, 1972); Powell, plate 5, fig. 2; plate 7, fig. 2
1992 Hystrichosphaeropsis sp. cf. H. obscura habib; Brinkhuis et al., plate 4, figs. 6-7
1992 Hystrichosphaeropsis complanata Eisenack, 1965; Engel, p. 111., plate 10.
1993 Hystrichosphaeropsis obscura habib, 1972; Martin, fig. 8F.
Manuscript holotype: Sample H 394/395, Sg. 29 e, Plate V, 5, 7, 9.
Etymology: referring to the small cyst size.
Type locality: Heumensoord well, near Heumensoord. The Netherlands
Type stratum: Veldhoven Formation
Diagnosis: A small bicavate elongate species of Hystrichosphaeropsis with a reduced apical pericoel. Usually a small apical horn is developed.
Dimensions: Height: pericyst: 70 (72) 75 µm; endocyst: 40 (45) 50 µm; Width: pericyst: 40 (42) 45 µm; endocyst: 40 (41) 45 µm. Apical horn: 0-5 µm. N = 20.
Description: A species of Hystrichosphaeropsis characterized by its small size. Peri- and endocyst are elongate in shape. The apical pericoel is small to almost lacking. Both the endo- and pericyst usually display a small apical horn. The periphragm is smooth to granular. The endophragm is smooth. The archeopyle is formed by the loss of paraplate 3’’. The operculum is free.
Discussion: the new species differs from the morphologically similar H obscura habib, 1972, in the size of the apical pericoel, which is only weakly developed in Hystrichosphaeropsis minimus. Furthermore, H. minimus is much smaller in size and its peripragm is not “densely granular” as in H. obscura. It differs from the morphologically similar Hystrichosphaeropsis arctica Matsuoka and Bujak, 1988, in lacking a coarsely reticulate distal; extremity and from Hystrichosphaeropsis variabilis Matsuoka and Bujak, 1988, in lacking high parasutural septa.
Occurrence: The Netherlands (this study), Italy (this study; Powell, 1986a; Brinkhuis et al., 1992), Australia (Martin, 1993) and North Atlantic (Engel, 1992)
Total stratigraphic range: Latest Late Oligocene to early Miocene (this study) see Fig. 5.
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Name not validly published: considered a manuscript name.
Holotype: Zevenboom, 1995, pl.5, figs.5,7,9.
Age: latest Late Oligocene-Early Miocene.
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Original description (Zevenboom, 1995)
Hystrichosphaeropsis minimus Zevenboom and Santarelli sp.nov. (manuscript name) (Plate V, 3, 6, 9)
?1972 Triblastula cf. sp. T. Borussica (Eisenack, 1954) Morgenroth, 1966; Benedek, p. 24; plate 3, fig. 13
1986a Hystrichosphaeropsis obscura (Habib, 1972); Powell, plate 5, fig. 2; plate 7, fig. 2
1992 Hystrichosphaeropsis sp. cf. H. obscura habib; Brinkhuis et al., plate 4, figs. 6-7
1992 Hystrichosphaeropsis complanata Eisenack, 1965; Engel, p. 111., plate 10.
1993 Hystrichosphaeropsis obscura habib, 1972; Martin, fig. 8F.
Manuscript holotype: Sample H 394/395, Sg. 29 e, Plate V, 5, 7, 9.
Etymology: referring to the small cyst size.
Type locality: Heumensoord well, near Heumensoord. The Netherlands
Type stratum: Veldhoven Formation
Diagnosis: A small bicavate elongate species of Hystrichosphaeropsis with a reduced apical pericoel. Usually a small apical horn is developed.
Dimensions: Height: pericyst: 70 (72) 75 µm; endocyst: 40 (45) 50 µm; Width: pericyst: 40 (42) 45 µm; endocyst: 40 (41) 45 µm. Apical horn: 0-5 µm. N = 20.
Description: A species of Hystrichosphaeropsis characterized by its small size. Peri- and endocyst are elongate in shape. The apical pericoel is small to almost lacking. Both the endo- and pericyst usually display a small apical horn. The periphragm is smooth to granular. The endophragm is smooth. The archeopyle is formed by the loss of paraplate 3’’. The operculum is free.
Discussion: the new species differs from the morphologically similar H obscura habib, 1972, in the size of the apical pericoel, which is only weakly developed in Hystrichosphaeropsis minimus. Furthermore, H. minimus is much smaller in size and its peripragm is not “densely granular” as in H. obscura. It differs from the morphologically similar Hystrichosphaeropsis arctica Matsuoka and Bujak, 1988, in lacking a coarsely reticulate distal; extremity and from Hystrichosphaeropsis variabilis Matsuoka and Bujak, 1988, in lacking high parasutural septa.
Occurrence: The Netherlands (this study), Italy (this study; Powell, 1986a; Brinkhuis et al., 1992), Australia (Martin, 1993) and North Atlantic (Engel, 1992)
Total stratigraphic range: Latest Late Oligocene to early Miocene (this study) see Fig. 5.
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