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Senoniasphaera macroreticulata
Senoniasphaera macroreticulata Prince et al., 2008, p.90, pl.1, fig.7–10.
Holotype: Prince et al., 2008, pl.1, figs.7–8.
Age: late Santonian–early Campanian.
Original description (Prince et al., 2008):
Senoniasphaera macroreticulata Prince, Jarvis, Pearce et Tocher sp. nov. ( Plate I, 7–11)
1990 Senoniasphaera protrusa Clarke et Verdier, 1967; Harker et al.; pl. 11, their Fig. 11 only (Campanian; Western Interior, North America).
Holotype: Slide PRC 3684, WCI C1, E/F ref. N43/3.
Paratype: Slide PRC 3685, WCI C2, E/F ref. U56/4.
Repository: Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, Wales, UK.
Type locality: Whitecliff, Isle of Wight, England.
Stratigraphic horizon: Basal lower Campanian, O. pilula Zone, base of the Whitecliff Ledge Beds.
Etymology: Macro, large, with reference to the large reticulations on the outer body.
Diagnosis: A species of Senoniasphaera with a densely reticulate outer body connected to the inner body by fairly long fibrous pillars. The cavities between these pillars are rectangular to sub-rectangular in shape but never oval or rounded as in Senoniasphaera protrusa. Paratabulation may be indicated on the dorsal side by a concentration of ornamentation. However, this is often obscured by the densely reticulate outer body.
Description: The inner body is round, oval or sub-rectangular, sometimes elongate, with a sub-triangular antapical horn. The position of this horn may be either central or offset such that the inner body is either symmetrical or asymmetrical. The inner body is connected to the outer by long (up to 10 µm) slender or broad pillars, which are generally wavy and perforate, appearing fibrous at low magnification. The cavation between the pillars is irregular in shape but never as strongly rounded or oval as in Senoniasphaera protrusa. The outer body is covered by a dense reticulation of variable size, which imparts an irregular, wavy outline. Slight indications of antapical and lateral horns may be visible. Due to the nature of the cavation (circumcavate), the mid-ventral area has reduced ornamentation. The archaeopyle is apical, type tA, sometimes attached, with a well-developed zigzag margin and an offset sulcul notch. Small accessory archaeopyle sutures may be visible.
Dimensions: Holotype: inner body 51 µm wide × 51 µm long, outer body 69 µm wide × 70 µm long. Range of 9 measured specimens: inner body 30–51 µm (average 39 µm) wide × 34–60 µm (average 47 µm) long; outer body (w/l) 54–69 µm (average 59 µm) wide × 55–80 µm (average 69 µm) long.
Comparison: This species differs from all other species of Senoniasphaera by the densely reticulate outer body and the form of the pillars. It differs from Canningia and Glaphyrocysta by having ornamentation that is absent or reduced on the mid-ventral area. Cyclonephelium has ornament that is reduced on both mid-ventral and mid-dorsal areas.
Stratigraphic range: This species was only seen in two samples from Kent (WTN 12, White Ness, upper Santonian mid-Uintacrinus socialis Zone, and FNP 9(2), Foreness Point, lower Campanian basal O. pilula (U. anglicus) Zone), but has an almost identical range to Senoniasphaera protrusa (WCI 90 to section top) at Whitecliff, Isle of Wight: middle Santonian (upper M. coranguinum Zone) to lower Campanian (O. pilula Zone).Comparison. Senoniasphaera clavelli sp. nov. is distinguished from Senoniasphaera jurassica by its significantly longer apical horn and prolate hypocyst. Senoniasphaera jurassica is usually circumcavate, whilst S. clavelli is more obviously bicavate.
Remarks: Senoniasphaera clavelli appears to be a ceratioid cyst, though an offset sulcal notch is often not recognisable and the cyst exhibits less dorso-ventral compression. We believe that this species forms part of an evolutionary lineage linking S. clavelli, S. jurassica and Muderongia simplex Alberti. Older morphotypes tend to have a slightly more rotund outline (see Figure 4c and 4i for comparison).
Holotype: Prince et al., 2008, pl.1, figs.7–8.
Age: late Santonian–early Campanian.
Original description (Prince et al., 2008):
Senoniasphaera macroreticulata Prince, Jarvis, Pearce et Tocher sp. nov. ( Plate I, 7–11)
1990 Senoniasphaera protrusa Clarke et Verdier, 1967; Harker et al.; pl. 11, their Fig. 11 only (Campanian; Western Interior, North America).
Holotype: Slide PRC 3684, WCI C1, E/F ref. N43/3.
Paratype: Slide PRC 3685, WCI C2, E/F ref. U56/4.
Repository: Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, Wales, UK.
Type locality: Whitecliff, Isle of Wight, England.
Stratigraphic horizon: Basal lower Campanian, O. pilula Zone, base of the Whitecliff Ledge Beds.
Etymology: Macro, large, with reference to the large reticulations on the outer body.
Diagnosis: A species of Senoniasphaera with a densely reticulate outer body connected to the inner body by fairly long fibrous pillars. The cavities between these pillars are rectangular to sub-rectangular in shape but never oval or rounded as in Senoniasphaera protrusa. Paratabulation may be indicated on the dorsal side by a concentration of ornamentation. However, this is often obscured by the densely reticulate outer body.
Description: The inner body is round, oval or sub-rectangular, sometimes elongate, with a sub-triangular antapical horn. The position of this horn may be either central or offset such that the inner body is either symmetrical or asymmetrical. The inner body is connected to the outer by long (up to 10 µm) slender or broad pillars, which are generally wavy and perforate, appearing fibrous at low magnification. The cavation between the pillars is irregular in shape but never as strongly rounded or oval as in Senoniasphaera protrusa. The outer body is covered by a dense reticulation of variable size, which imparts an irregular, wavy outline. Slight indications of antapical and lateral horns may be visible. Due to the nature of the cavation (circumcavate), the mid-ventral area has reduced ornamentation. The archaeopyle is apical, type tA, sometimes attached, with a well-developed zigzag margin and an offset sulcul notch. Small accessory archaeopyle sutures may be visible.
Dimensions: Holotype: inner body 51 µm wide × 51 µm long, outer body 69 µm wide × 70 µm long. Range of 9 measured specimens: inner body 30–51 µm (average 39 µm) wide × 34–60 µm (average 47 µm) long; outer body (w/l) 54–69 µm (average 59 µm) wide × 55–80 µm (average 69 µm) long.
Comparison: This species differs from all other species of Senoniasphaera by the densely reticulate outer body and the form of the pillars. It differs from Canningia and Glaphyrocysta by having ornamentation that is absent or reduced on the mid-ventral area. Cyclonephelium has ornament that is reduced on both mid-ventral and mid-dorsal areas.
Stratigraphic range: This species was only seen in two samples from Kent (WTN 12, White Ness, upper Santonian mid-Uintacrinus socialis Zone, and FNP 9(2), Foreness Point, lower Campanian basal O. pilula (U. anglicus) Zone), but has an almost identical range to Senoniasphaera protrusa (WCI 90 to section top) at Whitecliff, Isle of Wight: middle Santonian (upper M. coranguinum Zone) to lower Campanian (O. pilula Zone).Comparison. Senoniasphaera clavelli sp. nov. is distinguished from Senoniasphaera jurassica by its significantly longer apical horn and prolate hypocyst. Senoniasphaera jurassica is usually circumcavate, whilst S. clavelli is more obviously bicavate.
Remarks: Senoniasphaera clavelli appears to be a ceratioid cyst, though an offset sulcal notch is often not recognisable and the cyst exhibits less dorso-ventral compression. We believe that this species forms part of an evolutionary lineage linking S. clavelli, S. jurassica and Muderongia simplex Alberti. Older morphotypes tend to have a slightly more rotund outline (see Figure 4c and 4i for comparison).