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Deflandrea coronata
Deflandrea coronata McIntyre, 1975
Now Manumiella. Originally Deflandrea, subsequently Isabelia (combination illegitimate), thirdly Isabelidinium, fourthly Eurydinium, fifthly (and now) Manumiella. Age:
Holotypus: McIntyre, 1975, pl.3, figs.1,2
Locus typicus: Horton River, N.W.T., Canada
Stratum typicum: "Pale shale zone", Campanian
Original diagnosis: McIntyre, 1975, p.64
Cyst cavate, dorsoventrally flattened, somewhat hexagonal in dorsoventral view, protruding markedly laterally in the equatorial region, and divided into approximately equal epitract and hypotract by a slightly laevorotatory cingulum. On the epitract the periblast normally bulges pronouncedly above the top of the endoblast to form shoulders which are usually square and flat topped. A blunt-ended apical horn 15-25 Ám long occurs on top of the shoulders and is often inclined slightly to the dorsal surface. Left antapical horn usually short and pointed; right antapical horn is a triangular bulge. The cingulum is about 7 Ám wide and is bordered on its anterior and posterior margins by discontinuous ridges usually consisting of rows of pustules that are sometimes joined. Occasionally the ridge pieces consist of clavae. The 7 pieces on the epitractal side represent the precingular reflected plates and the 5 hypotractal side pieces, the postcingular reflected plates. The ridge pieces are usually of different lengths, depending on the reflected plate they represent, but they are not always seen clearly and sometimes appear as continuous ridges (Pl. 3, fig. 4). In some specimens the ridge piece of reflected plate 4" is not seen (Pl. 3, fig. 4). A large, wide sulcus on the ventral surface usually has margins indicated by folds or, occasionally, a row of pustules. The large intercalary (2a) archeopyle is hexagonal and the angles are usually rounded. Normally anterior margin significantly longer (2 or 3 times) than posterior margin.
Operculum usually remains attached at posterior margin. No other indications of tabulation are visible. The tabulation is probably of typical peridinioid type 4" 3a 7" 5""" 2"""". Endoblast large, usually folded at its margins, and always separated laterally from periblast but probably attached dorsally. A large pericoel is present. Sometimes a ring of verrucae occurs on the endoblast but, these may indicate the margin of dorsal attachment of the endoblast to the periblast. Endophragm about 1/2 Ám thick and smooth to faintly scabrate. Periphragm less than 1 Ám thick and smooth to faintly scabrate. Pustules scattered over the periphragm but no definite pattern can be seen. Density of pustules variable, some specimens having very few (Pl. 3, fig. 3).
Dimensions: Holotype, 168 Ám long, 122 Ám wide; endoblast, 73 Ám long, 85 Ám wide; range, 140-190 Ám long, 90-125 Ám wide; endoblast, 50-70 Ám long, 60-901Ám wide.
Now Manumiella. Originally Deflandrea, subsequently Isabelia (combination illegitimate), thirdly Isabelidinium, fourthly Eurydinium, fifthly (and now) Manumiella. Age:
Holotypus: McIntyre, 1975, pl.3, figs.1,2
Locus typicus: Horton River, N.W.T., Canada
Stratum typicum: "Pale shale zone", Campanian
Original diagnosis: McIntyre, 1975, p.64
Cyst cavate, dorsoventrally flattened, somewhat hexagonal in dorsoventral view, protruding markedly laterally in the equatorial region, and divided into approximately equal epitract and hypotract by a slightly laevorotatory cingulum. On the epitract the periblast normally bulges pronouncedly above the top of the endoblast to form shoulders which are usually square and flat topped. A blunt-ended apical horn 15-25 Ám long occurs on top of the shoulders and is often inclined slightly to the dorsal surface. Left antapical horn usually short and pointed; right antapical horn is a triangular bulge. The cingulum is about 7 Ám wide and is bordered on its anterior and posterior margins by discontinuous ridges usually consisting of rows of pustules that are sometimes joined. Occasionally the ridge pieces consist of clavae. The 7 pieces on the epitractal side represent the precingular reflected plates and the 5 hypotractal side pieces, the postcingular reflected plates. The ridge pieces are usually of different lengths, depending on the reflected plate they represent, but they are not always seen clearly and sometimes appear as continuous ridges (Pl. 3, fig. 4). In some specimens the ridge piece of reflected plate 4" is not seen (Pl. 3, fig. 4). A large, wide sulcus on the ventral surface usually has margins indicated by folds or, occasionally, a row of pustules. The large intercalary (2a) archeopyle is hexagonal and the angles are usually rounded. Normally anterior margin significantly longer (2 or 3 times) than posterior margin.
Operculum usually remains attached at posterior margin. No other indications of tabulation are visible. The tabulation is probably of typical peridinioid type 4" 3a 7" 5""" 2"""". Endoblast large, usually folded at its margins, and always separated laterally from periblast but probably attached dorsally. A large pericoel is present. Sometimes a ring of verrucae occurs on the endoblast but, these may indicate the margin of dorsal attachment of the endoblast to the periblast. Endophragm about 1/2 Ám thick and smooth to faintly scabrate. Periphragm less than 1 Ám thick and smooth to faintly scabrate. Pustules scattered over the periphragm but no definite pattern can be seen. Density of pustules variable, some specimens having very few (Pl. 3, fig. 3).
Dimensions: Holotype, 168 Ám long, 122 Ám wide; endoblast, 73 Ám long, 85 Ám wide; range, 140-190 Ám long, 90-125 Ám wide; endoblast, 50-70 Ám long, 60-901Ám wide.