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Durotrigia aspera
Durotrigia aspera Bailey and Partington, 1991
Holotype: Bailey and Partington, 1991, pl.2, figs.1-2, text-fig.4
Locus typicus: UKCS Well 9/9b-4Z at 12314", North Sea
Stratum typicum: Bathonian
Original diagnosis: Bailey and Partington, 1991, p.246
A species of Durotrigia with full gonyaulacoid tabulation reflected by irregular, undulose ridges and low crests, which often develop proximal vacuoles. The autophragm is relatively thick and intratabular areas are coarsely granulate, vermiculate or semi-reticulate. The archaeopyle is variable precingular, type 1P-5P. Average size c.70x55 Ám (holotype 62x48 Ám).
Original description: Bailey and Partington, 1991, p.248
This species is of intermediate size (70-90 Ám) and has a subspherical or ovoid shape. Specimens with several precingular operculae missing are often crumpled and shapeless. Parasutural features comprise low undulose ridges or crests, which often develop proximal vacuoles. Intratabular areas exhibit a coarse ornamentation of isolated or coalescing granules and verrniculae. The para sutural ridges reflect a gonyaulacoid tabulation (4", 2a, 6", 6c, 6""", 1p, 1"""", ?5s, fpa). The autophragm is relatively thick (1-2 Ám) and the archaeopyle is formed by the loss of between one and five precingular plates. Excystment begins dorsally at the 3" position and progresses ventrally in both directions. In the holotype, only one precingular operculum has fully operated, but cysts with variable dehiscence; 1P, 2P, 3P, 4P and 5P have been recorded.
Affinities:
Bailey and Partington, 1991, p.248: Durotrigia aspera differs from other species of the genus by the style of the parasutural features and the very coarse intratabular ornament.
Holotype: Bailey and Partington, 1991, pl.2, figs.1-2, text-fig.4
Locus typicus: UKCS Well 9/9b-4Z at 12314", North Sea
Stratum typicum: Bathonian
Original diagnosis: Bailey and Partington, 1991, p.246
A species of Durotrigia with full gonyaulacoid tabulation reflected by irregular, undulose ridges and low crests, which often develop proximal vacuoles. The autophragm is relatively thick and intratabular areas are coarsely granulate, vermiculate or semi-reticulate. The archaeopyle is variable precingular, type 1P-5P. Average size c.70x55 Ám (holotype 62x48 Ám).
Original description: Bailey and Partington, 1991, p.248
This species is of intermediate size (70-90 Ám) and has a subspherical or ovoid shape. Specimens with several precingular operculae missing are often crumpled and shapeless. Parasutural features comprise low undulose ridges or crests, which often develop proximal vacuoles. Intratabular areas exhibit a coarse ornamentation of isolated or coalescing granules and verrniculae. The para sutural ridges reflect a gonyaulacoid tabulation (4", 2a, 6", 6c, 6""", 1p, 1"""", ?5s, fpa). The autophragm is relatively thick (1-2 Ám) and the archaeopyle is formed by the loss of between one and five precingular plates. Excystment begins dorsally at the 3" position and progresses ventrally in both directions. In the holotype, only one precingular operculum has fully operated, but cysts with variable dehiscence; 1P, 2P, 3P, 4P and 5P have been recorded.
Affinities:
Bailey and Partington, 1991, p.248: Durotrigia aspera differs from other species of the genus by the style of the parasutural features and the very coarse intratabular ornament.