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Leptodinium formosum
Leptodinium formosum Singh, 1983
Holotype: Singh, 1983, pl.48, fig.6-7; Jan du Chêne et al., 1986, pl.71, figs.2-3
Locus typicus: Upper Shaftesbury Formation of the Peace River area, Canada
Stratum typicum: Early Cenomanian
Original description: Singh, 1983, p. 140
Proximate cysts with a subcircular to rounded pentagonal outline; length to width ratio close to 1.0; surface ornamented by closely spaced, 0.5- to 1-micron wide, dome-shaped verrucae; parasutural crests very low, smooth, and delineating a gonyaulacacean paratabulation of 4", 6", 6c, 6""", 1p, 1""""; paraplate 1" elongate and distinctly longer than the paraplate 4"; paracingulum strongly helicoidal, about 5 microns wide, and subdivided into six rectangular paraplates; ventral ends of the paracingulum offset by two to three cingular widths; parasulcus slightly sinuous, wider at the anterior end, and slightly inclined to the right; archeopyle precingular, type P (3" only); operculum free.
Affinities:
Singh, 1983, p. 140: Leptodinium formosum can be distinguished from Leptodinium modicum Brideaux and Mclntyre, 1975, which has only five postcingular (1""" to 5""") paraplates, distinctly higher parasutural crests, a smooth surface, and a rounded pentagonal outline. L. formosum is distinct from Leptodinium cancellatum Brideaux and Mclntyre, 1975, which has only five postcingular (1""" to 5""") paraplates and a vermiculate-reticulate intratabular ornamentation forming a trellis-like pattern.
Holotype: Singh, 1983, pl.48, fig.6-7; Jan du Chêne et al., 1986, pl.71, figs.2-3
Locus typicus: Upper Shaftesbury Formation of the Peace River area, Canada
Stratum typicum: Early Cenomanian
Original description: Singh, 1983, p. 140
Proximate cysts with a subcircular to rounded pentagonal outline; length to width ratio close to 1.0; surface ornamented by closely spaced, 0.5- to 1-micron wide, dome-shaped verrucae; parasutural crests very low, smooth, and delineating a gonyaulacacean paratabulation of 4", 6", 6c, 6""", 1p, 1""""; paraplate 1" elongate and distinctly longer than the paraplate 4"; paracingulum strongly helicoidal, about 5 microns wide, and subdivided into six rectangular paraplates; ventral ends of the paracingulum offset by two to three cingular widths; parasulcus slightly sinuous, wider at the anterior end, and slightly inclined to the right; archeopyle precingular, type P (3" only); operculum free.
Affinities:
Singh, 1983, p. 140: Leptodinium formosum can be distinguished from Leptodinium modicum Brideaux and Mclntyre, 1975, which has only five postcingular (1""" to 5""") paraplates, distinctly higher parasutural crests, a smooth surface, and a rounded pentagonal outline. L. formosum is distinct from Leptodinium cancellatum Brideaux and Mclntyre, 1975, which has only five postcingular (1""" to 5""") paraplates and a vermiculate-reticulate intratabular ornamentation forming a trellis-like pattern.