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Chatangiella ditissima
Chatangiella ditissima, (McIntyre, 1975), Lentin and Williams, 1976
Tax. jr. synonym of Chatangiella decorosa (McIntyre, 1975) Lentin and Williams, 1976, according to Harker and Sarjeant in Harker et al., 1990. Harker and Sarjeant in Harker et al., 1990, retained Chatangiella ditissima as a separate species.
Holotype: McIntyre, 1975, pl.1, figs.1-2
Locus typicus: Horton River, N.W.T., Canada
Stratum typicum: Santonian-Maastrichtian
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Original description as Deflandrea ditissima: [McIntyre, 1975, p. 62]:
Description:
Cyst cavate, dorsoventrally flattened, approximately pentagonal in dorsoventral view, protruding laterally in equatorial region and divided equally into epitract and hypotract by a slightly laevorotatory cingulum. On the epitract the periblast usually bulges above the level of the endoblast to form rounded shoulders, which vary in their degree of development. A blunt-ended, broad-based apical horn 15-25 µm long is produced from the shoulders. Left antapical horn sharply pointed and about 10-15 µm long; the short right antapical horn usually appears as an angular bulge. Cingulum about 7 µm wide and bordered on both sides by discontinuous ridges consisting of rows of pustules that may join to form narrow grooves. Anterior margin of cingulum has 7 pieces of ridge and posterior margin has 5 pieces of ridge. These apparently represent 7 precingular and 5 postcingular reflected plates. Cingulum ridge pieces are of different lengths, according to the reflected plates they represent. Each ridge piece normally has an arc of intratabular pustules from one end to the other on its reflected plate. A large wide sulcus is usually seen on the ventral surface. Four rows of small pustules or granules, indicating the margins of the apical reflected plates, are present on the apical horn, which is probably capped by 1 preapical reflected plate.
The large intercalary (2a) archeopyle is rounded hexagonal to broadly rounded hexagonal in shape. Occasionally anterior margin considerably longer than posterior margin). Operculum often attached at posterior margin. Endoblast usually has an archeopyle indicated by 2 breaks. This is probably also an intercalary archeopyle, although it appears apical. Indications of other intercalary reflected plates have not been seen in this species nor have apical to intercalary, and intercalary to precingular reflected plate boundaries been seen. The evidence available suggests that the tabulation is 4' 3a 7'' 5''' 2''''.
Endoblast large, with smooth endophragm about 1/2 µm thick. Anterior and posterior ends of endoblast folded and flattened.
The periphragm is less than 1 µm thick and is smooth, except for the pustules described above and occasional pits, which may be less well-developed pustules or perhaps corrosion features. The endophragm and periphragm are apparently fused in the region of the cingulum and pre- and postcingular reflected plates, and only one wall layer is visible laterally in this region. Large apical and antapical pericoels are present.
Dimensions:
Holotype, 147 µm long, 80 µm wide; endoblast, 53 µm long; range, 115-150 µm long, 60--90 µm wide; endoblast, 40-60 µm long.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Chatangiella ditissima (McIntyre, 1975) Lentin and Williams, 1976 is approximately pentagonal with an equatorial bulge and divided equally into epicyst and hypocyst. Well rounded shoulders developed. The blunt-ended, broad-based apical horn is 15-25 Fm long. Left antapical horn sharply pointed, 10-15 Fm long, short right antapical horn. Cingulum bordered by discontinuous ridges consisting of rows of pustules.
Size: length 115-150 Fm, breadth 60-90 Fm.
Tax. jr. synonym of Chatangiella decorosa (McIntyre, 1975) Lentin and Williams, 1976, according to Harker and Sarjeant in Harker et al., 1990. Harker and Sarjeant in Harker et al., 1990, retained Chatangiella ditissima as a separate species.
Holotype: McIntyre, 1975, pl.1, figs.1-2
Locus typicus: Horton River, N.W.T., Canada
Stratum typicum: Santonian-Maastrichtian
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Original description as Deflandrea ditissima: [McIntyre, 1975, p. 62]:
Description:
Cyst cavate, dorsoventrally flattened, approximately pentagonal in dorsoventral view, protruding laterally in equatorial region and divided equally into epitract and hypotract by a slightly laevorotatory cingulum. On the epitract the periblast usually bulges above the level of the endoblast to form rounded shoulders, which vary in their degree of development. A blunt-ended, broad-based apical horn 15-25 µm long is produced from the shoulders. Left antapical horn sharply pointed and about 10-15 µm long; the short right antapical horn usually appears as an angular bulge. Cingulum about 7 µm wide and bordered on both sides by discontinuous ridges consisting of rows of pustules that may join to form narrow grooves. Anterior margin of cingulum has 7 pieces of ridge and posterior margin has 5 pieces of ridge. These apparently represent 7 precingular and 5 postcingular reflected plates. Cingulum ridge pieces are of different lengths, according to the reflected plates they represent. Each ridge piece normally has an arc of intratabular pustules from one end to the other on its reflected plate. A large wide sulcus is usually seen on the ventral surface. Four rows of small pustules or granules, indicating the margins of the apical reflected plates, are present on the apical horn, which is probably capped by 1 preapical reflected plate.
The large intercalary (2a) archeopyle is rounded hexagonal to broadly rounded hexagonal in shape. Occasionally anterior margin considerably longer than posterior margin). Operculum often attached at posterior margin. Endoblast usually has an archeopyle indicated by 2 breaks. This is probably also an intercalary archeopyle, although it appears apical. Indications of other intercalary reflected plates have not been seen in this species nor have apical to intercalary, and intercalary to precingular reflected plate boundaries been seen. The evidence available suggests that the tabulation is 4' 3a 7'' 5''' 2''''.
Endoblast large, with smooth endophragm about 1/2 µm thick. Anterior and posterior ends of endoblast folded and flattened.
The periphragm is less than 1 µm thick and is smooth, except for the pustules described above and occasional pits, which may be less well-developed pustules or perhaps corrosion features. The endophragm and periphragm are apparently fused in the region of the cingulum and pre- and postcingular reflected plates, and only one wall layer is visible laterally in this region. Large apical and antapical pericoels are present.
Dimensions:
Holotype, 147 µm long, 80 µm wide; endoblast, 53 µm long; range, 115-150 µm long, 60--90 µm wide; endoblast, 40-60 µm long.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Chatangiella ditissima (McIntyre, 1975) Lentin and Williams, 1976 is approximately pentagonal with an equatorial bulge and divided equally into epicyst and hypocyst. Well rounded shoulders developed. The blunt-ended, broad-based apical horn is 15-25 Fm long. Left antapical horn sharply pointed, 10-15 Fm long, short right antapical horn. Cingulum bordered by discontinuous ridges consisting of rows of pustules.
Size: length 115-150 Fm, breadth 60-90 Fm.