Back
Trichodinium piaseckii
From Fensome et al., 2019:
Trichodinium piaseckii Bailey et al., 1997, p.239,241, figs.3g–k.
Holotype: Bailey et al., 1997, fig.3h.
Age: late Kimmeridgian.
Original description (Bailey et al., 1997):
Trichodinium piaseckii sp. nov. (Figure 3g-k)
---------------------------------------------------------------------------------------------------
Diagnosis: a speices of Trichodinium with a broadly rounded hypocyst, epicyst bearing a solid apical horn. The surface of the autophragm is ornamented more or less evenly by a covering of short (2-5 µm), moderately spaced acuminate spines. Spine features particularly strong and dense antapically. Archeopyle precingular, type P (3’’’), size range 60-90 µm.
Type locality: Kimmeridge Clay Formation, Marton, north Yorkshire. Bed 12 of Cope (1974), uppermost Pectinatites hudlestonii Zone
Derivation of name: In honor of Dr. Stefan Piasecki of the Greenland Geological Survey.
Description:
Shape|: cyst subspherical to subpentagonal
Wall relations: autophragm only.
Wall features: the autophragm is relatively thin, ornamented on the outer surface by simple, acuminate spines 2-5 µm in length. These spines are moderately spaced, with bases not overlapping or connecting. The apical horn is a short, but distinct tuft-like solid structure, composed of fused sporopollenin fibers. Antapically, the ornamentation is both stronger and more dense, with some of the larger spines having capitate or briefly bifid distal terminations.
Paratabulation: the paracingulam is sometimes faintly discernible from alignment of spines.
Archeopyle: precingular, type P (3’’ only)
Dimensions: size range 60-90 µm overall length. Holotype 96 µm length, 108 µm width.
Comparison: This species differs from other of the genus in possessing a more or less even covering of short, simple spines which are openly spaced. There are no parasutural or pandasutural features, though spines may be reduced over the center of larger paraplates. It is similar to Trichodinium speetonense Davey, 1974, which the spinose ornament is absent from pandasutural and parasulcal zones. Trichodinium castanea (Deflandre) Clarke and Verdier, 1967, possesses spines which are generally truncated, capitate or bifid distally. Trichodinium ciliatum tends to be more spherical and does not have an apical horn.
Occurrence: Kimmeridgian (Pectinatites hudlestoni, Pectinatites pectinatus Zones) of Marton, North yorkshire (this study), kimmeridgian (pavlovia rotunda Zone) of Dorset, southern England (PM, personal observations), Kimmeridgian of the Barents Sea, Norwegian Sea and North Sea areas (personal observations).
Trichodinium piaseckii Bailey et al., 1997, p.239,241, figs.3g–k.
Holotype: Bailey et al., 1997, fig.3h.
Age: late Kimmeridgian.
Original description (Bailey et al., 1997):
Trichodinium piaseckii sp. nov. (Figure 3g-k)
---------------------------------------------------------------------------------------------------
Diagnosis: a speices of Trichodinium with a broadly rounded hypocyst, epicyst bearing a solid apical horn. The surface of the autophragm is ornamented more or less evenly by a covering of short (2-5 µm), moderately spaced acuminate spines. Spine features particularly strong and dense antapically. Archeopyle precingular, type P (3’’’), size range 60-90 µm.
Type locality: Kimmeridge Clay Formation, Marton, north Yorkshire. Bed 12 of Cope (1974), uppermost Pectinatites hudlestonii Zone
Derivation of name: In honor of Dr. Stefan Piasecki of the Greenland Geological Survey.
Description:
Shape|: cyst subspherical to subpentagonal
Wall relations: autophragm only.
Wall features: the autophragm is relatively thin, ornamented on the outer surface by simple, acuminate spines 2-5 µm in length. These spines are moderately spaced, with bases not overlapping or connecting. The apical horn is a short, but distinct tuft-like solid structure, composed of fused sporopollenin fibers. Antapically, the ornamentation is both stronger and more dense, with some of the larger spines having capitate or briefly bifid distal terminations.
Paratabulation: the paracingulam is sometimes faintly discernible from alignment of spines.
Archeopyle: precingular, type P (3’’ only)
Dimensions: size range 60-90 µm overall length. Holotype 96 µm length, 108 µm width.
Comparison: This species differs from other of the genus in possessing a more or less even covering of short, simple spines which are openly spaced. There are no parasutural or pandasutural features, though spines may be reduced over the center of larger paraplates. It is similar to Trichodinium speetonense Davey, 1974, which the spinose ornament is absent from pandasutural and parasulcal zones. Trichodinium castanea (Deflandre) Clarke and Verdier, 1967, possesses spines which are generally truncated, capitate or bifid distally. Trichodinium ciliatum tends to be more spherical and does not have an apical horn.
Occurrence: Kimmeridgian (Pectinatites hudlestoni, Pectinatites pectinatus Zones) of Marton, North yorkshire (this study), kimmeridgian (pavlovia rotunda Zone) of Dorset, southern England (PM, personal observations), Kimmeridgian of the Barents Sea, Norwegian Sea and North Sea areas (personal observations).