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Carpodinium glabrum
From Fensome et al., 2019:
Carpodinium glabrum Duxbury, 2019, p.181, pl.16, figs.1–3,5–6. Holotype: Duxbury, 2019, pl.16, figs.1,5. Age: late Barremian.
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Original description: [Duxbury, 2019, p. 181]:
Carpodinium glabrum Duxbury n. sp.
Plate 16, Figures 1–3, 5, 6
Carpodinium granulatum Cookson and Eisenack 1962 emend. Leffingwell and Morgan 1977 in DUXBURY 1980, pl. 3, fig. 7
Holotype: Plate 16, Figures 1, 5.
Type Locality: Heslerton No. 2 at 29.85 m (core chip), late Barremian age. Holotype: E.F. B38.0.
Derivation of Name: From the Latin glabrum, hairless, smooth – in reference to the lack of ornament.
Diagnosis: A smooth, elongate ovoidal species with a hyaline endocyst and a prominent apical horn. Wall layers closely appressed over most plates, but with marked suturocavation. Small, circular holes are occasionally present within the main plate areas. Sutural crests are regularly to irregularly denticulate, marking a tabulation of ?', 6'', ?c, 5 - 6''', 1p, 1pv, 1'''', and denticles surrounding the antapical plate may be significantly better-developed than elsewhere. A prominent ventral pericoel displays three or more perforations of varying sizes, presumably reflecting the perisulcal plates, so that in some cases this produces a ventral “string bag” effect. The archeopyle is single-plate precingular (3'').
Dimensions: Holotype: Length - 66 µm. Width - 46 µm.
Overall: Length - 66 (65) 63 µm; Width - 46 (41) 35 µm.
Specimens Measured: 8.
Remarks: No determination of the apical or cingular series has been possible here. Although cingular crests are often well developed, the cingulum tends to be featureless with wall layers closely appressed.
In their comprehensive emendation and comments on Carpodinium granulatum, Leffingwell and Morgan (1977, p. 297, 298) described a wide morphological range, similar in several respects to Carpodinium glabrum. However, their description of sutural crests of the antapical plate, “developed weakly, if at all” contrasts with those of C. glabrum, which bears prominent, denticulate crests (Plate 16, Figures 1, 3). Also, their descriptions and graphical illustrations (op. cit. text-fig. 6) show none of the ventral cavation or fenestration typical of C. glabrum.
The specimens referred to Carpodinium granulatum by Duxbury (1980) are included in Carpodinium glabrum here; the characteristic ventral pericoel is clearly illustrated in Duxbury (op. cit., Plate 3, Figure 7).
The age range of C. glabrum appears to be restricted within the late Barremian and in the present study it occurred only in the deepest 4 samples analysed in Heslerton No. 2 and in a single sample (11,210.00 ft) in well 22/26a-2, in both cases assigned to palynofloral Subzone LKP21.1. This is well below the Aptian inception of Carpodinium granulatum in Australia noted by Leffingwell and Morgan (op. cit., p. 301) and figured by Morgan (1980, Figure 8). An English late Aptian FAD was recorded for C. granulatum in Duxbury 1983, text-figs. 2–4.
Carpodinium glabrum Duxbury, 2019, p.181, pl.16, figs.1–3,5–6. Holotype: Duxbury, 2019, pl.16, figs.1,5. Age: late Barremian.
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Original description: [Duxbury, 2019, p. 181]:
Carpodinium glabrum Duxbury n. sp.
Plate 16, Figures 1–3, 5, 6
Carpodinium granulatum Cookson and Eisenack 1962 emend. Leffingwell and Morgan 1977 in DUXBURY 1980, pl. 3, fig. 7
Holotype: Plate 16, Figures 1, 5.
Type Locality: Heslerton No. 2 at 29.85 m (core chip), late Barremian age. Holotype: E.F. B38.0.
Derivation of Name: From the Latin glabrum, hairless, smooth – in reference to the lack of ornament.
Diagnosis: A smooth, elongate ovoidal species with a hyaline endocyst and a prominent apical horn. Wall layers closely appressed over most plates, but with marked suturocavation. Small, circular holes are occasionally present within the main plate areas. Sutural crests are regularly to irregularly denticulate, marking a tabulation of ?', 6'', ?c, 5 - 6''', 1p, 1pv, 1'''', and denticles surrounding the antapical plate may be significantly better-developed than elsewhere. A prominent ventral pericoel displays three or more perforations of varying sizes, presumably reflecting the perisulcal plates, so that in some cases this produces a ventral “string bag” effect. The archeopyle is single-plate precingular (3'').
Dimensions: Holotype: Length - 66 µm. Width - 46 µm.
Overall: Length - 66 (65) 63 µm; Width - 46 (41) 35 µm.
Specimens Measured: 8.
Remarks: No determination of the apical or cingular series has been possible here. Although cingular crests are often well developed, the cingulum tends to be featureless with wall layers closely appressed.
In their comprehensive emendation and comments on Carpodinium granulatum, Leffingwell and Morgan (1977, p. 297, 298) described a wide morphological range, similar in several respects to Carpodinium glabrum. However, their description of sutural crests of the antapical plate, “developed weakly, if at all” contrasts with those of C. glabrum, which bears prominent, denticulate crests (Plate 16, Figures 1, 3). Also, their descriptions and graphical illustrations (op. cit. text-fig. 6) show none of the ventral cavation or fenestration typical of C. glabrum.
The specimens referred to Carpodinium granulatum by Duxbury (1980) are included in Carpodinium glabrum here; the characteristic ventral pericoel is clearly illustrated in Duxbury (op. cit., Plate 3, Figure 7).
The age range of C. glabrum appears to be restricted within the late Barremian and in the present study it occurred only in the deepest 4 samples analysed in Heslerton No. 2 and in a single sample (11,210.00 ft) in well 22/26a-2, in both cases assigned to palynofloral Subzone LKP21.1. This is well below the Aptian inception of Carpodinium granulatum in Australia noted by Leffingwell and Morgan (op. cit., p. 301) and figured by Morgan (1980, Figure 8). An English late Aptian FAD was recorded for C. granulatum in Duxbury 1983, text-figs. 2–4.