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Gillinia pyriformis
Gillinia ppyriformis Marshall, 1990a, p.14,16, figs.7A-H,17D-O.
Holotype: Marshall, 1990a, figs.7G,17F-H; Fensome et al., 1996, figs.1-3,14 - p.2311.
Age: Campanian.
Original description: Marshall, 1990, p.14, 16
Ventrodorsal outline of cyst rounded subtriangular. Lateral margins occasionally nearly straight to convex; usually concave above equator, convex below this level. Antapical margin nearly straight to convex. Each lateral margin near apex bearing a thin, dome-shaped membrane up to 7-12 µm high. Domes often ruptured or crumpled distally. Only autophragm (thickness c. 0.5 µm) discernible over most of cyst; two layers apparent in areas with domes. Cyst surface smooth, extended around periphery of cyst to form parasutural ridges and septa up to 5-4 µm high. Septa highest just below and above the domes; crests smooth, irregular, or rarely denticulate. Only parts of paraplates discernible. Intersection of septa at paraplate triple junctions on antapical margin forming thickened pillars, with usually 2-4 pillars evident on individual specimens. Archeopyle at apex, type uncertain, autophragm appearing thinner in this area.
Dimensions. Length 23(26)30 µm, width 23(27)33 µm (15 specimens excluding septa).
Type material. Holotype (Fig. 17F-H) cyst length 24 µm, width 24 µm.
Affinities:
Marshall, 1990, p.16: This form differs from Gillinia hymenophora (Fig. 17A-C) in its ventrodorsal outline, and the restriction of septa to the periphery of the cyst. A comparison of specimen outlines and arrangement of septa on these species is given in Fig. 7. The interpretation that the thickened junctions between septa on the antapical margin of G. pyriformis are located at paraplate triple junctions was only apparent after comparisons with the more complete paratabulation pattern evident on C. hymenophora.
Holotype: Marshall, 1990a, figs.7G,17F-H; Fensome et al., 1996, figs.1-3,14 - p.2311.
Age: Campanian.
Original description: Marshall, 1990, p.14, 16
Ventrodorsal outline of cyst rounded subtriangular. Lateral margins occasionally nearly straight to convex; usually concave above equator, convex below this level. Antapical margin nearly straight to convex. Each lateral margin near apex bearing a thin, dome-shaped membrane up to 7-12 µm high. Domes often ruptured or crumpled distally. Only autophragm (thickness c. 0.5 µm) discernible over most of cyst; two layers apparent in areas with domes. Cyst surface smooth, extended around periphery of cyst to form parasutural ridges and septa up to 5-4 µm high. Septa highest just below and above the domes; crests smooth, irregular, or rarely denticulate. Only parts of paraplates discernible. Intersection of septa at paraplate triple junctions on antapical margin forming thickened pillars, with usually 2-4 pillars evident on individual specimens. Archeopyle at apex, type uncertain, autophragm appearing thinner in this area.
Dimensions. Length 23(26)30 µm, width 23(27)33 µm (15 specimens excluding septa).
Type material. Holotype (Fig. 17F-H) cyst length 24 µm, width 24 µm.
Affinities:
Marshall, 1990, p.16: This form differs from Gillinia hymenophora (Fig. 17A-C) in its ventrodorsal outline, and the restriction of septa to the periphery of the cyst. A comparison of specimen outlines and arrangement of septa on these species is given in Fig. 7. The interpretation that the thickened junctions between septa on the antapical margin of G. pyriformis are located at paraplate triple junctions was only apparent after comparisons with the more complete paratabulation pattern evident on C. hymenophora.