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Deflandrea diebelii ssp. rigida
Deflandrea diebelii ssp. rigida May, 1980
Now Cerodinium diebelii ssp. rigida. Originally Deflandrea diebelii ssp. rigida, subsequently (and now) Cerodinium diebelii ssp. rigidum. See also Ceratiopsis diebelii ssp. rigida (combination illegitimate).
Holotype: May, 1980, pl.8, figs.9,15
Locus typicus: Atlantic Highlands, New Jersey
Stratum typicum: Navesink Formation, Maastrichtian
Original description: May, 1980, p.75-76
Periblast rigid in construction, peridinioid, triangular in outline, bearing extended apical and antapical horns of similar length, which are generally broader based and more tapering than in D. diebeli. Equatorial margins are enlarged slightly outward, terminating in oblique angles at lateral margins of cingulum.
Periphragm finely wrinkled longitudinally, except within sulcus. Endoblast ovoidal, loosely filling the central cavity, leaving small lateral pericoels and large anterior and posterior pericoels within the horns, beginning near the bases of the horns, measuring roughly the same length as the endoblast. Endophragm is smooth. No tabulation observed on either wall layer. Cingulum strongly developed on periphragm and faintly developed on endophragm, formed of parallel periphragm equatorial folds somewhat crenulated by intersecting longitudinal wrinkles of periphragm. Vertical, closely-spaced wrinkles occur within cingulum. Cingulum weakly levorotatory; occasionally nonspiral. Sulcus extends from terminal ends of cingulum, broadening posteriorly, bounded by subtle folds directed toward antapical horn tips. Archeopyle intercalary (Type I/I), attentuated hexagonal with alternating long and short sides, occupying ca. 2/3 of medial dorsal epitract; operculum seldom found in place.
Discussion: D. diebeli subsp. rigida differs from D. diebeli mainly in its robust, regularly striate structure. Periphragm is not "draped" over endoblast, but rather forms a rigid, generally nonflexuous periblast, with a well-marked and striate cingulum.
Dimensions: Holotype L x W, 292 x 115 Ám; endoblast length 103 Á, apical horn above endoblast 103 Ám; antapical horns beneath endoblast ca. 103 Ám each. Observed range (45 specimens measured): length 237--248 Ám, width 71--118 Ám; apical and antapical horn length approximately equal to endoblast length.
Now Cerodinium diebelii ssp. rigida. Originally Deflandrea diebelii ssp. rigida, subsequently (and now) Cerodinium diebelii ssp. rigidum. See also Ceratiopsis diebelii ssp. rigida (combination illegitimate).
Holotype: May, 1980, pl.8, figs.9,15
Locus typicus: Atlantic Highlands, New Jersey
Stratum typicum: Navesink Formation, Maastrichtian
Original description: May, 1980, p.75-76
Periblast rigid in construction, peridinioid, triangular in outline, bearing extended apical and antapical horns of similar length, which are generally broader based and more tapering than in D. diebeli. Equatorial margins are enlarged slightly outward, terminating in oblique angles at lateral margins of cingulum.
Periphragm finely wrinkled longitudinally, except within sulcus. Endoblast ovoidal, loosely filling the central cavity, leaving small lateral pericoels and large anterior and posterior pericoels within the horns, beginning near the bases of the horns, measuring roughly the same length as the endoblast. Endophragm is smooth. No tabulation observed on either wall layer. Cingulum strongly developed on periphragm and faintly developed on endophragm, formed of parallel periphragm equatorial folds somewhat crenulated by intersecting longitudinal wrinkles of periphragm. Vertical, closely-spaced wrinkles occur within cingulum. Cingulum weakly levorotatory; occasionally nonspiral. Sulcus extends from terminal ends of cingulum, broadening posteriorly, bounded by subtle folds directed toward antapical horn tips. Archeopyle intercalary (Type I/I), attentuated hexagonal with alternating long and short sides, occupying ca. 2/3 of medial dorsal epitract; operculum seldom found in place.
Discussion: D. diebeli subsp. rigida differs from D. diebeli mainly in its robust, regularly striate structure. Periphragm is not "draped" over endoblast, but rather forms a rigid, generally nonflexuous periblast, with a well-marked and striate cingulum.
Dimensions: Holotype L x W, 292 x 115 Ám; endoblast length 103 Á, apical horn above endoblast 103 Ám; antapical horns beneath endoblast ca. 103 Ám each. Observed range (45 specimens measured): length 237--248 Ám, width 71--118 Ám; apical and antapical horn length approximately equal to endoblast length.