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Evansia granulata
Evansia granulata Pocock, 1972
Originally (and now) Evansia, subsequently Glomodinium.
Arhus et al., 1989, transferred this species to Glomodinium Dodekova, 1975. Lentin and Williams, 1993, retained the species in Evansia.
Holotype: Pocock, 1972, pl.24, fig.7; Jansonius, 1986, pl.5, figs.1-3, text-fig.10a-b
Locus typicus: Imperial Tidewater Wapella, W Canada
Stratum typicum: Late Bajocian
Original description: Pocock, 1972, p.95
Vesicle dorso-ventrally flattened; outline oval with short projecting apical horn; archeopyle intercalary with simple free operculum; no plating visible; transverse and longitudinal furrows not detectable; theca two-layered comprising an inner smoothly rounded capsule about 0.5 Ám thick overlain by a tightly enveloping outer granulose layer 1.0-1.5 Ám thick; finely and closely granulose, giving the surface a spongy appearance; apical horn solid; about 10.0 Ám Iong; antapically a small process about 2.0 Ám long formed by thickening of the outer layer; colourless; theca 58.3x40.7 Ám; capsule 44.0x37.4 Ám.
Supplemental description: Jansonius, 1986, p.210
(Holotype) 58.5 x 42 Ám overall, dorsal face up. Wall consisting of a proportionally thin hyaline inner layer (0.3-0.4 Ám), overlain by a granulose-spongy outer layer, individual granules (in part extended into spinules, rods or clavae) up to 1.5 Ám tall, but generally not much more (or less) than 1 Ám. The granular layer is more or less reduced over the apical horn, which carries some thin cilia near its tip. Dorsal side showing a nearly square, weakly hexagonal 2a plate faintly delineated by a narrow groove cutting through the granular outer layer; its angled adcingular delineation passes over the lower part of a nucleus inside the grain (chromatophores?); the angled anterior margins of la and 3a are only barely differentiated. The cingulum is incompletely indicated by a small bulge and slightly reduced granular layer on the left margin, a tear on the right margin, and a vague groove connecting these two features. No other paratabulation can be discerned except for a rudimentary right antapical process, and a slightly thinned ventral sulcal area. Because of folding of an original near-spherical body with a thin wall, several large crescentic folds are produced; the largest of these lies under the intercalary plates, and suggests the presence of a spherical inner body. This is an illusion however; the central cavity is continuous into the apical horn.
Originally (and now) Evansia, subsequently Glomodinium.
Arhus et al., 1989, transferred this species to Glomodinium Dodekova, 1975. Lentin and Williams, 1993, retained the species in Evansia.
Holotype: Pocock, 1972, pl.24, fig.7; Jansonius, 1986, pl.5, figs.1-3, text-fig.10a-b
Locus typicus: Imperial Tidewater Wapella, W Canada
Stratum typicum: Late Bajocian
Original description: Pocock, 1972, p.95
Vesicle dorso-ventrally flattened; outline oval with short projecting apical horn; archeopyle intercalary with simple free operculum; no plating visible; transverse and longitudinal furrows not detectable; theca two-layered comprising an inner smoothly rounded capsule about 0.5 Ám thick overlain by a tightly enveloping outer granulose layer 1.0-1.5 Ám thick; finely and closely granulose, giving the surface a spongy appearance; apical horn solid; about 10.0 Ám Iong; antapically a small process about 2.0 Ám long formed by thickening of the outer layer; colourless; theca 58.3x40.7 Ám; capsule 44.0x37.4 Ám.
Supplemental description: Jansonius, 1986, p.210
(Holotype) 58.5 x 42 Ám overall, dorsal face up. Wall consisting of a proportionally thin hyaline inner layer (0.3-0.4 Ám), overlain by a granulose-spongy outer layer, individual granules (in part extended into spinules, rods or clavae) up to 1.5 Ám tall, but generally not much more (or less) than 1 Ám. The granular layer is more or less reduced over the apical horn, which carries some thin cilia near its tip. Dorsal side showing a nearly square, weakly hexagonal 2a plate faintly delineated by a narrow groove cutting through the granular outer layer; its angled adcingular delineation passes over the lower part of a nucleus inside the grain (chromatophores?); the angled anterior margins of la and 3a are only barely differentiated. The cingulum is incompletely indicated by a small bulge and slightly reduced granular layer on the left margin, a tear on the right margin, and a vague groove connecting these two features. No other paratabulation can be discerned except for a rudimentary right antapical process, and a slightly thinned ventral sulcal area. Because of folding of an original near-spherical body with a thin wall, several large crescentic folds are produced; the largest of these lies under the intercalary plates, and suggests the presence of a spherical inner body. This is an illusion however; the central cavity is continuous into the apical horn.