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Inversidinium exilimurum
Inversidinium exilimurum McLean, 1973
Tax. jr. synonym of Wetzeliella subgen. Rhombodinium (now Palaeotetradinium) minusculum Alberti, 1961, according to Stover and Evitt, 1978.
Inversidinium minusculum therefore becomes the correct name for the type species of Inversidinium, but the nomenclatural type of the genus remains the holotype of Inversidinium exilimurum.
Holotype: McLean, 1973, pl.90, figs.1-2; Fensome et al., 1993, p.1163, figs.1-2
Locus typicus: Stafford County, Virginia, USA
Stratum typicum: Late Paleocene
Original diagnosis: McLean, 1973, p.730
Bi-layered cyst; periblast outline peridinioid with pointed apex and truncated antapex; lacks indications of tabulation; endoblast outline variable. Convex-outward folds of the periblast reflect cingulum and sulcus. Excystment apparatus (= archeopyle?) antapical; forms by rupture of antapical tips of periblast and endoblast. Periphragm and endophragm externally smooth to granulose.
Original description: McLean, 1973, p.732
Periphragm transverse section elliptical at widest part and triangular at antapex. Endoblast dorso-ventral outline roundly triangular with elliptical transverse section at widest part and triangular cross section at antapex; endoblast occupies hypotractal portion of periblast. A narrow convex-outward fold 1-3 Ám wide traverses periblast dorsal surface at its widest part; a similar fold extends longitudinally along the periblast ventral midline from the antapex to about midway between the widest part of the periblast and the apex. Excystment apparatus (=archeopyle?) forms by posterior tip of endophragm breaking away and posterior tip of periphragm rupturing irregularly. Periphragm and endophragm less than 1 Ám thick, transparent, and externally smooth to granulose.
Size: Holotype: length 50 Ám, width 40 Ám Range of 11 specimens length 45(51)60 Ám, width 32(41)52 Ám.
Tax. jr. synonym of Wetzeliella subgen. Rhombodinium (now Palaeotetradinium) minusculum Alberti, 1961, according to Stover and Evitt, 1978.
Inversidinium minusculum therefore becomes the correct name for the type species of Inversidinium, but the nomenclatural type of the genus remains the holotype of Inversidinium exilimurum.
Holotype: McLean, 1973, pl.90, figs.1-2; Fensome et al., 1993, p.1163, figs.1-2
Locus typicus: Stafford County, Virginia, USA
Stratum typicum: Late Paleocene
Original diagnosis: McLean, 1973, p.730
Bi-layered cyst; periblast outline peridinioid with pointed apex and truncated antapex; lacks indications of tabulation; endoblast outline variable. Convex-outward folds of the periblast reflect cingulum and sulcus. Excystment apparatus (= archeopyle?) antapical; forms by rupture of antapical tips of periblast and endoblast. Periphragm and endophragm externally smooth to granulose.
Original description: McLean, 1973, p.732
Periphragm transverse section elliptical at widest part and triangular at antapex. Endoblast dorso-ventral outline roundly triangular with elliptical transverse section at widest part and triangular cross section at antapex; endoblast occupies hypotractal portion of periblast. A narrow convex-outward fold 1-3 Ám wide traverses periblast dorsal surface at its widest part; a similar fold extends longitudinally along the periblast ventral midline from the antapex to about midway between the widest part of the periblast and the apex. Excystment apparatus (=archeopyle?) forms by posterior tip of endophragm breaking away and posterior tip of periphragm rupturing irregularly. Periphragm and endophragm less than 1 Ám thick, transparent, and externally smooth to granulose.
Size: Holotype: length 50 Ám, width 40 Ám Range of 11 specimens length 45(51)60 Ám, width 32(41)52 Ám.