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Pseudoceratium brevicornutum
From Fensome et al., 2019:
Pseudoceratium brevicornutum Herngreen et al., 2000, p.50, pl.9, figs.6–7. Holotype: Herngreen et al., 2000, pl.9, fig.6; Fensome et al., 2019a, fig.18P. Questionable assignment: Fensome et al. (2019a, p.51). Taxonomic junior synonym: Pseudoceratium eopelliferum (name not validly published), according to Herngreen et al. (2000, p.50). Age: late Ryazanian–early Hauterivian.
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Original description: [Herngreen et al., 2000, p. 50]:
Pseudoceratium brevicornutum new species
(P1.9,6-7)
1979 Pseudoceratium pelliferum Gocht 19b7;
Davey, p.65, pl. 4, fig. 1
1982 Pseudoceratium peIliferum Gocht;
Davey, pl. 10, fig 16
1987 Pseudoceratium "eopelliferum"; RRl, p. 50-51, pl. 26, fig. 1
1987 Pseudoceratium sp. 'l; Heilmann-Clausen, p.21, fig. 4 (93)
1994 Pseudoceratium ‘eopelliferum’; Herngreen et al. fig, 14
Holotype: Well 102-03, 1585 m, laboratory nr. 2103-3/9, Pl. 9, fig. 6.
Type stratum: Vlieland Claystone Formation
Etymology: After the relatively short horns.
Description: Proximate cyst, compressed ceratoid with single short apical, antapical and postcingular horns. Apical archaeopyle, type tA, suture zig-zag, parasulcal notch offset, operculum free. Paratabulation usually indicated by archeopyle only. Wall with numerous dense, short bifurcate or capitate intratabular processes. The length and width of the central body are approximately equal.
Dimensions: Holotype: 114x60 um, horns: apical 21 um, antapical 15 um and postcingular 6 um; range: 78-120x45- 60 um (3 complete specimens measured) and 60-69x51-57 um (3 hypocysts); horns; apical 18-24 um, antapical 11-18 um and postcingular 6-12 um.
Discussion: This new species differs from all other representatives of Pseudoceratium by the shorter horns and the approximately equal length and width of the central body. Stratigraphic range: ln his compilation Heilmann-Clausen (1987) indicated an uppermost Ryazanian to Lower Valanginian range, however ammonite control is missing. Herngreen et al. (1994), on the basis of RRI (1987), accepted the top occurrence in the Early Hauterivian regalrs Zone; however Davey (in a letter of 10 January 1995) would regard this as reworked from the Valanginian. This study Late(st) Ryazanian to Early Valanginian Central North Sea Graben: Vlieland Claystone Formation (e.g. 102- 03) and Schill Grund Member (e.9. F15-02). Other internal reports: Late(st) Ryazanian-Early Hauterivian (wells De Wyk-05, Gildehaus Sandstone; Ruinen-01, Gildehaus Sandstone; Tubbergen-06, Bentheim Claystone, Bentheim Sandstone and Schoonebeek members; Westerbork-O1, Bentheim Sandstone and Wettrup-O3, Germany, Toniges Zwischenmittel and Dichotomiten Sandstein).
Repository: NITG-TNO, collection Mesozoic Palynology, holotype single grain mount 100/557.
Remarks: Davey (1979) already noted that some specimens of Pseudoceratium pelliferumfrom upper Ryazanian and lowest Valanginian strata have reduced horns and tend to be broader than younger specimens. Davey (1982) stressed the wide body and short horns of this early representative of P. pelliferum. RRI also mentioned these features and added that P. "eopelliferum" most closely resembles and morphologically grades into P. pelliferum. Heilmann-Clausen (1987) considered this species as an early variety of Pseudoceratium pelliferum.
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Comments Fensome et al., 2019a:
This species differs from Pseudoceratium pelliferum in having distinctly shorter horns. In fact, the lateral horn on the holotype (Herngreen et al. 2000, pl. 9, fig. 6) is not clearly developed and so we questionably retain this species in Pseudoceratium. The other illustrated specimen (Herngreen et al. 2000, pl. 9, fig. 7) might be conspecific with Pseudoceratium pelliferum, albeit with a shorter than average horn.
Stratigraphical occurrence. Herngreen et al. (2000) recorded the range of this species from the North Sea and The Netherlands as upper Ryazanian (middle Berriasian) to lower Hauterivian.
Pseudoceratium brevicornutum Herngreen et al., 2000, p.50, pl.9, figs.6–7. Holotype: Herngreen et al., 2000, pl.9, fig.6; Fensome et al., 2019a, fig.18P. Questionable assignment: Fensome et al. (2019a, p.51). Taxonomic junior synonym: Pseudoceratium eopelliferum (name not validly published), according to Herngreen et al. (2000, p.50). Age: late Ryazanian–early Hauterivian.
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Original description: [Herngreen et al., 2000, p. 50]:
Pseudoceratium brevicornutum new species
(P1.9,6-7)
1979 Pseudoceratium pelliferum Gocht 19b7;
Davey, p.65, pl. 4, fig. 1
1982 Pseudoceratium peIliferum Gocht;
Davey, pl. 10, fig 16
1987 Pseudoceratium "eopelliferum"; RRl, p. 50-51, pl. 26, fig. 1
1987 Pseudoceratium sp. 'l; Heilmann-Clausen, p.21, fig. 4 (93)
1994 Pseudoceratium ‘eopelliferum’; Herngreen et al. fig, 14
Holotype: Well 102-03, 1585 m, laboratory nr. 2103-3/9, Pl. 9, fig. 6.
Type stratum: Vlieland Claystone Formation
Etymology: After the relatively short horns.
Description: Proximate cyst, compressed ceratoid with single short apical, antapical and postcingular horns. Apical archaeopyle, type tA, suture zig-zag, parasulcal notch offset, operculum free. Paratabulation usually indicated by archeopyle only. Wall with numerous dense, short bifurcate or capitate intratabular processes. The length and width of the central body are approximately equal.
Dimensions: Holotype: 114x60 um, horns: apical 21 um, antapical 15 um and postcingular 6 um; range: 78-120x45- 60 um (3 complete specimens measured) and 60-69x51-57 um (3 hypocysts); horns; apical 18-24 um, antapical 11-18 um and postcingular 6-12 um.
Discussion: This new species differs from all other representatives of Pseudoceratium by the shorter horns and the approximately equal length and width of the central body. Stratigraphic range: ln his compilation Heilmann-Clausen (1987) indicated an uppermost Ryazanian to Lower Valanginian range, however ammonite control is missing. Herngreen et al. (1994), on the basis of RRI (1987), accepted the top occurrence in the Early Hauterivian regalrs Zone; however Davey (in a letter of 10 January 1995) would regard this as reworked from the Valanginian. This study Late(st) Ryazanian to Early Valanginian Central North Sea Graben: Vlieland Claystone Formation (e.g. 102- 03) and Schill Grund Member (e.9. F15-02). Other internal reports: Late(st) Ryazanian-Early Hauterivian (wells De Wyk-05, Gildehaus Sandstone; Ruinen-01, Gildehaus Sandstone; Tubbergen-06, Bentheim Claystone, Bentheim Sandstone and Schoonebeek members; Westerbork-O1, Bentheim Sandstone and Wettrup-O3, Germany, Toniges Zwischenmittel and Dichotomiten Sandstein).
Repository: NITG-TNO, collection Mesozoic Palynology, holotype single grain mount 100/557.
Remarks: Davey (1979) already noted that some specimens of Pseudoceratium pelliferumfrom upper Ryazanian and lowest Valanginian strata have reduced horns and tend to be broader than younger specimens. Davey (1982) stressed the wide body and short horns of this early representative of P. pelliferum. RRI also mentioned these features and added that P. "eopelliferum" most closely resembles and morphologically grades into P. pelliferum. Heilmann-Clausen (1987) considered this species as an early variety of Pseudoceratium pelliferum.
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Comments Fensome et al., 2019a:
This species differs from Pseudoceratium pelliferum in having distinctly shorter horns. In fact, the lateral horn on the holotype (Herngreen et al. 2000, pl. 9, fig. 6) is not clearly developed and so we questionably retain this species in Pseudoceratium. The other illustrated specimen (Herngreen et al. 2000, pl. 9, fig. 7) might be conspecific with Pseudoceratium pelliferum, albeit with a shorter than average horn.
Stratigraphical occurrence. Herngreen et al. (2000) recorded the range of this species from the North Sea and The Netherlands as upper Ryazanian (middle Berriasian) to lower Hauterivian.