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Pterodinium cingulatum ssp. exile
Pterodinium ssp. excile Marheinecke, 1992, p. 40.
Contrary to the opinion of Lentin and Williams (1993, p.551), Williams et al. (1998, p.517) considered this name to be validly published.
Holotype: Marheinecke, 1992, pl.5, figs.7-9
Age: Early Maastrichtian
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Original description: [Marheinecke, 1992] (translated from German):
Derivatio nominis: Exilis (Latin) of low mass, after the weakly developed septa.
Holotype: The specimen RIV.10/6 from K868 shown on Plate 5, Fig. 7-9. Locus typicus: Former writing chalk pit Hemmoor (Lower Saxony).
Stratum typicum: Upper. Lower Maastrichtian (sumensis zone), writing chalk.
Description: Cyst habitus spheroidal. Wall composed of pedium and luxuria. The luxuria forms finite septa.
Surface ornamentation: Shagrenate.
Septal structure: Muri claudate to rarely apertate, conflat. Cannae are not developed. Free of ornamentation. The septa are smooth-margined to serrate and of very constant height.
Process structure: Similar to the basal region of normal gonal processes, the septa in the gonal points enclose cavities that may be open distally. In the gonal points, the septa are not or only slightly higher
Apical region: Only 2' and 3' are fully developed. 1' and 4' fuse to form a mostly isocameral area. A small apical horn from the apical septa may be present. Cingulum: Sinistral, offset by at least one cingulum width.
Sulcal region: The sulcus is almost undifferentiated, usually straight and broad. Area 6" is approximately triangular, and the septum to the sulcus may be absent. Area 1'" is fused with the sulcus. Sometimes septa within the sulcus clearly demarcate areas ps, rs, and as.
Areation: 3-4', 6", 6c, 5-6", 1p, 1", Xs.
Archeopyle: 3". Operculum: 3", secate.
Additional note: The septa appear significantly weaker overall than in the nomionate subspecies and are somewhat lower on average
Comparison: Pterodinium c. exile is distinguished from the nominate subspecies by the better differentiated sulcus, the entire-margined septa, and the missing rudimentary processes.
Specimens: >50
Holotype statistics:
Length of central capsule: 45.
Width of central capsule: 40.
Thickness of central capsule: 42.
Height of septa: 4-5.
Statistics:
Length of central capsule: 37(42)46.
Width of central capsule: 34(39)42.
Thickness of central capsule: 34(39)41.
Height of septa: 4-5.
Measured specimens: 11.
Contrary to the opinion of Lentin and Williams (1993, p.551), Williams et al. (1998, p.517) considered this name to be validly published.
Holotype: Marheinecke, 1992, pl.5, figs.7-9
Age: Early Maastrichtian
-------------------------------------------------------------------------------------------------------------------------------
Original description: [Marheinecke, 1992] (translated from German):
Derivatio nominis: Exilis (Latin) of low mass, after the weakly developed septa.
Holotype: The specimen RIV.10/6 from K868 shown on Plate 5, Fig. 7-9. Locus typicus: Former writing chalk pit Hemmoor (Lower Saxony).
Stratum typicum: Upper. Lower Maastrichtian (sumensis zone), writing chalk.
Description: Cyst habitus spheroidal. Wall composed of pedium and luxuria. The luxuria forms finite septa.
Surface ornamentation: Shagrenate.
Septal structure: Muri claudate to rarely apertate, conflat. Cannae are not developed. Free of ornamentation. The septa are smooth-margined to serrate and of very constant height.
Process structure: Similar to the basal region of normal gonal processes, the septa in the gonal points enclose cavities that may be open distally. In the gonal points, the septa are not or only slightly higher
Apical region: Only 2' and 3' are fully developed. 1' and 4' fuse to form a mostly isocameral area. A small apical horn from the apical septa may be present. Cingulum: Sinistral, offset by at least one cingulum width.
Sulcal region: The sulcus is almost undifferentiated, usually straight and broad. Area 6" is approximately triangular, and the septum to the sulcus may be absent. Area 1'" is fused with the sulcus. Sometimes septa within the sulcus clearly demarcate areas ps, rs, and as.
Areation: 3-4', 6", 6c, 5-6", 1p, 1", Xs.
Archeopyle: 3". Operculum: 3", secate.
Additional note: The septa appear significantly weaker overall than in the nomionate subspecies and are somewhat lower on average
Comparison: Pterodinium c. exile is distinguished from the nominate subspecies by the better differentiated sulcus, the entire-margined septa, and the missing rudimentary processes.
Specimens: >50
Holotype statistics:
Length of central capsule: 45.
Width of central capsule: 40.
Thickness of central capsule: 42.
Height of septa: 4-5.
Statistics:
Length of central capsule: 37(42)46.
Width of central capsule: 34(39)42.
Thickness of central capsule: 34(39)41.
Height of septa: 4-5.
Measured specimens: 11.