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Rhynchodiniopsis obesa
Rhynchidiniopsis obesa (Brideaux, 1971) Sarjeant, 1982
Now Cribroperidinium?. Originally Gonyaulacysta, subsequently Millioudodinium, thirdly Rhynchodiniopsis, fourthly (and now) Cribroperidinium?. Holotype: Brideaux, 1971, pl.23, fig.39, text-fig.8a,b; Jan du Chêne et al., 1986, pl.30, fig.9 Locus typicus: Alberta, Canada Stratum typicum: Late Albian
Original description (Holotype): Brideaux, 1971, p.82: Gonyaulacysta obesa
Length, 126 µm; width, 94 µm; apical horn, 32 µm. Main cyst pentagonal-rounded in shape; epitract including apical horn longer than hypotract; antapex rounded. Apical horn stout. Cingulum helicoid, sinistral, displaced about two cingulum widths (10 µm); low, somewhat denticulate ledges outline the cingulum course. Sulcus slightly sinuous, extending onto the epitract, terminated apically by plate 1", antapically by plate 1pv. Tabulation determined as ?4", 6", 0c, 6""", 1pv, 1"""", the intertabular regions marked by a microreticulate sculpture. Archeopyle not developed.
Description: Brideaux, 1971, p.82: Gonyaulacysta obesa
Dinoflagellate cyst; outline more or less pentagonal; epitract and hypotract approximately equal in length, excluding the apical horn. Antapex rounded. Prominent, stout apical horn, often somewhat truncated. Cingulum helicoid, sinistral, displaced about one to two cingulum widths; sulcus slightly sinuous, extending onto the epitract, subtended by plate 1" apically and plate Ipv antapically. Reflected tabulation of 3--?4", 6", 0c, 6""", 1pv, 1"""" marked by low sutures; most specimens exhibit a microreticulate intratabular sculpture, the muri narrow and the lumina rounded to polygonal. Archaeopyle precingular; the operculum formed of plate 3".
Dimensions: Length on 12 measured specimens, 122--140 µm; width on 11 measured specimens, 88--111 µm; length of apical horn on 12 measured specimens, 21--35 µm. Total of 18 specimens recovered.
Affinities:
Brideaux, 1971, p.82: Gonyaulacysta obesa
The combination of the shape, stout apical horn, intratabular microreticulation and plating pattern serve to distinguish this species from other forms described under Gonyaulacysta.
Now Cribroperidinium?. Originally Gonyaulacysta, subsequently Millioudodinium, thirdly Rhynchodiniopsis, fourthly (and now) Cribroperidinium?. Holotype: Brideaux, 1971, pl.23, fig.39, text-fig.8a,b; Jan du Chêne et al., 1986, pl.30, fig.9 Locus typicus: Alberta, Canada Stratum typicum: Late Albian
Original description (Holotype): Brideaux, 1971, p.82: Gonyaulacysta obesa
Length, 126 µm; width, 94 µm; apical horn, 32 µm. Main cyst pentagonal-rounded in shape; epitract including apical horn longer than hypotract; antapex rounded. Apical horn stout. Cingulum helicoid, sinistral, displaced about two cingulum widths (10 µm); low, somewhat denticulate ledges outline the cingulum course. Sulcus slightly sinuous, extending onto the epitract, terminated apically by plate 1", antapically by plate 1pv. Tabulation determined as ?4", 6", 0c, 6""", 1pv, 1"""", the intertabular regions marked by a microreticulate sculpture. Archeopyle not developed.
Description: Brideaux, 1971, p.82: Gonyaulacysta obesa
Dinoflagellate cyst; outline more or less pentagonal; epitract and hypotract approximately equal in length, excluding the apical horn. Antapex rounded. Prominent, stout apical horn, often somewhat truncated. Cingulum helicoid, sinistral, displaced about one to two cingulum widths; sulcus slightly sinuous, extending onto the epitract, subtended by plate 1" apically and plate Ipv antapically. Reflected tabulation of 3--?4", 6", 0c, 6""", 1pv, 1"""" marked by low sutures; most specimens exhibit a microreticulate intratabular sculpture, the muri narrow and the lumina rounded to polygonal. Archaeopyle precingular; the operculum formed of plate 3".
Dimensions: Length on 12 measured specimens, 122--140 µm; width on 11 measured specimens, 88--111 µm; length of apical horn on 12 measured specimens, 21--35 µm. Total of 18 specimens recovered.
Affinities:
Brideaux, 1971, p.82: Gonyaulacysta obesa
The combination of the shape, stout apical horn, intratabular microreticulation and plating pattern serve to distinguish this species from other forms described under Gonyaulacysta.