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Evansia evittii
Evansia evittii (Pocock, 1972) Jansonius, 1986
Originally Tenua Eisenack, 1958, subsequently Pareodinia, thirdly Glomodinium, fourthly (and now) Evansia.
Tax. sr. synonym of Pareodinia tripartita Johnson and Hills, 1973, according to Wiggins, 1975, and Lentin and Williams, 1989.
Tax. sr. synonym of Pareodinia tripartita var. rotunda Johnson and Hills, 1973, according to Wiggins, 1975, and Below, 1990.
Holotype: Pocock, 1972, pl.24, fig.8 (lost according to Jansonius, 1986)
Lectotype: Jansonius, 1986, pl.6, figs.8-9 (designated by Jansonius, 1986)
Locus typicus: Royalite DeWinton, W Canada
Stratum typicum: Late Bajocian-Callovian
Original description: Pocock, 1972, p.94-95: Tenua evittii
Vesicle dorso-ventrally flattened; outline oval with short projecting apical horn; archeopyle apical, suture indicating offset sulcal notch; apical portion of test plated, six hexagonal precingular plates normally being detectable; test about 1.0 Ám thick; ornamented with small, closely packed granules; granules all about the same size (0.5 Ám diameter approx.) except at the tip of the apical horn where one or two small blunt-tipped processes may be developed (see diagram); colour yellow orange. Grain size 45.0-52.0x59.0-60.0 Ám, Holotype 45.0x59.0 Ám (including apical horn). Apical horn 10.0 Ám approximately, Holotype 10.0 Ám.
Supplemental description: Jansonius, 1986, p.210
(Lectotype) 55x43 Ám, ventral side (with large crescent fold across shoulders) up. Wall about 1.2 Ám thick; inner layer dense, hyaline, ca 0.4 Ám, internally smooth; outer layer densely granulose, granules round, ca 0.3 Ám, tightly appressed to inner layer and even in thickness all over. Cyst more or less spherical, with a short rounded, conical apical horn. No evidence of paratabulation other than a vague but definite thinning over the cingulum (5 Ám wide) and distinct grooves in the granular layer delineating three anterior intercalaries, of which 2a and 3a are clearly bounded by a geniculate anterior and posterior margin (1a does not show a clear delineation). The cingulum is slightly spiralling, and ventrally merges with a narrow sulcal area.
Affinities:
Jansonius, 1986, p.210: The sculpture is essentially finer and more uniform than in E. granulata, although only few specimens were examined, the overall habitus is sufficiently different to warrant the continuation of the two specific identities as proposed by Pocock.
Originally Tenua Eisenack, 1958, subsequently Pareodinia, thirdly Glomodinium, fourthly (and now) Evansia.
Tax. sr. synonym of Pareodinia tripartita Johnson and Hills, 1973, according to Wiggins, 1975, and Lentin and Williams, 1989.
Tax. sr. synonym of Pareodinia tripartita var. rotunda Johnson and Hills, 1973, according to Wiggins, 1975, and Below, 1990.
Holotype: Pocock, 1972, pl.24, fig.8 (lost according to Jansonius, 1986)
Lectotype: Jansonius, 1986, pl.6, figs.8-9 (designated by Jansonius, 1986)
Locus typicus: Royalite DeWinton, W Canada
Stratum typicum: Late Bajocian-Callovian
Original description: Pocock, 1972, p.94-95: Tenua evittii
Vesicle dorso-ventrally flattened; outline oval with short projecting apical horn; archeopyle apical, suture indicating offset sulcal notch; apical portion of test plated, six hexagonal precingular plates normally being detectable; test about 1.0 Ám thick; ornamented with small, closely packed granules; granules all about the same size (0.5 Ám diameter approx.) except at the tip of the apical horn where one or two small blunt-tipped processes may be developed (see diagram); colour yellow orange. Grain size 45.0-52.0x59.0-60.0 Ám, Holotype 45.0x59.0 Ám (including apical horn). Apical horn 10.0 Ám approximately, Holotype 10.0 Ám.
Supplemental description: Jansonius, 1986, p.210
(Lectotype) 55x43 Ám, ventral side (with large crescent fold across shoulders) up. Wall about 1.2 Ám thick; inner layer dense, hyaline, ca 0.4 Ám, internally smooth; outer layer densely granulose, granules round, ca 0.3 Ám, tightly appressed to inner layer and even in thickness all over. Cyst more or less spherical, with a short rounded, conical apical horn. No evidence of paratabulation other than a vague but definite thinning over the cingulum (5 Ám wide) and distinct grooves in the granular layer delineating three anterior intercalaries, of which 2a and 3a are clearly bounded by a geniculate anterior and posterior margin (1a does not show a clear delineation). The cingulum is slightly spiralling, and ventrally merges with a narrow sulcal area.
Affinities:
Jansonius, 1986, p.210: The sculpture is essentially finer and more uniform than in E. granulata, although only few specimens were examined, the overall habitus is sufficiently different to warrant the continuation of the two specific identities as proposed by Pocock.