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Rhynchodiniopsis canadensis
Rhynchidiniopsis canadensis (Pocock, 1972) Jansonius, 1986
Originally Gonyaulacysta, subsequently Hystrichogonyaulax, thirdly Rhynchodiniopsis.
Tax. jr. synonym of Rhynchodiniopsis (as Gonyaulacysta) cladophora (Deflandre, 1938) Below, 1981, according to Fisher and Riley, 1980. Jansonius, 1986 retained Rhynchodiniopsis canadensis as a separate species, but Kunz, 1990 agreed with Fisher and Riley, 1980.
Holotype: Pocock, 1972, pl.24, fig.1; Jan du Chêne et al., 1986, pl.97, fig.1-4
Locus typicus: Western Canada
Stratum typicum: Oxfordian-Kimmeridgian
Original description: Pocock, 1972, p.89: Gonyaualcysta canadensis
Vesicle more or less isodiametric; epitheca and hypotheca hemispherical; epitheca tapers towards the apex, being terminated by a short apical horn about 10.0 µm long and 12.0 µm wide (see diagram); hypotheca smoothly rounded; no antapical processes; transverse furrow helicoidal; strongly developed, longitudinal furrow less well marked; parallel-sided; tabulation 4", 6", 6""", 1""""; archeopyle precingular with a simple free operculum, comprises plate 3", not always developed; sutures reflected onto surface of vesicle as low raised ridges up to 1.0 µm wide; rows of thin, pinnate spines 2.5 (4.0) 7.7 µm long and up to 1.0 µm wide, spaced 2.0 (4.1) 8.8 µm apart line the crests of the ridges; vesicle two-layered; capsule very thin, smooth; outer layer 1.0-1.5 µm thick; scabrate; colour pale yellow; length of vesicle 99.0 (104.5) 110.0 µm; width of vesicle 77.0 (91.4) 106.0 µm.
Supplemental descirption: Jansonius, 1986, p.214, 216
(Holotype) Epicyst broadly conical, hypocyst broadly rounded; paratabulation marked by thin ridges, in part topped by scattered, irregularly spaced spines (1.5-5 µm tall; 0.5-1.25 µm wide) generally of cylindrical shape, but some swollen at the base or in the middle, and most (especially the coarser ones) with a minute distal bifurcation. At apical pole two preapical plates are separated by relatively strong ridges which terminate apically in a cluster (crown) of broadly lobate "spines" (1 x 1.5 µm), producing a short protruding apical "horn" (7.5 µm wide, 9 µm high). No trace of an internal body (or apical pericoel) can be observed. In general, the wall is developed as in G. downiei, here also thicker in the hypocyst.
The operculum of the 3" archeopyle is missing; its gabled anterior margin is flattened by the intercalation of two (or three?) anterior intercalary plates.
Affinites:
Jansonius, 1986, p. 216: The type assemblage contains many specimens readily identifiable as conspecific; the species was also recognized in other samples, again quite close to the type. It differs from R. cladophora (Defl.) Below in the finer sutural ridges and the more distinctly cylindrical spines inserted on them.
Originally Gonyaulacysta, subsequently Hystrichogonyaulax, thirdly Rhynchodiniopsis.
Tax. jr. synonym of Rhynchodiniopsis (as Gonyaulacysta) cladophora (Deflandre, 1938) Below, 1981, according to Fisher and Riley, 1980. Jansonius, 1986 retained Rhynchodiniopsis canadensis as a separate species, but Kunz, 1990 agreed with Fisher and Riley, 1980.
Holotype: Pocock, 1972, pl.24, fig.1; Jan du Chêne et al., 1986, pl.97, fig.1-4
Locus typicus: Western Canada
Stratum typicum: Oxfordian-Kimmeridgian
Original description: Pocock, 1972, p.89: Gonyaualcysta canadensis
Vesicle more or less isodiametric; epitheca and hypotheca hemispherical; epitheca tapers towards the apex, being terminated by a short apical horn about 10.0 µm long and 12.0 µm wide (see diagram); hypotheca smoothly rounded; no antapical processes; transverse furrow helicoidal; strongly developed, longitudinal furrow less well marked; parallel-sided; tabulation 4", 6", 6""", 1""""; archeopyle precingular with a simple free operculum, comprises plate 3", not always developed; sutures reflected onto surface of vesicle as low raised ridges up to 1.0 µm wide; rows of thin, pinnate spines 2.5 (4.0) 7.7 µm long and up to 1.0 µm wide, spaced 2.0 (4.1) 8.8 µm apart line the crests of the ridges; vesicle two-layered; capsule very thin, smooth; outer layer 1.0-1.5 µm thick; scabrate; colour pale yellow; length of vesicle 99.0 (104.5) 110.0 µm; width of vesicle 77.0 (91.4) 106.0 µm.
Supplemental descirption: Jansonius, 1986, p.214, 216
(Holotype) Epicyst broadly conical, hypocyst broadly rounded; paratabulation marked by thin ridges, in part topped by scattered, irregularly spaced spines (1.5-5 µm tall; 0.5-1.25 µm wide) generally of cylindrical shape, but some swollen at the base or in the middle, and most (especially the coarser ones) with a minute distal bifurcation. At apical pole two preapical plates are separated by relatively strong ridges which terminate apically in a cluster (crown) of broadly lobate "spines" (1 x 1.5 µm), producing a short protruding apical "horn" (7.5 µm wide, 9 µm high). No trace of an internal body (or apical pericoel) can be observed. In general, the wall is developed as in G. downiei, here also thicker in the hypocyst.
The operculum of the 3" archeopyle is missing; its gabled anterior margin is flattened by the intercalation of two (or three?) anterior intercalary plates.
Affinites:
Jansonius, 1986, p. 216: The type assemblage contains many specimens readily identifiable as conspecific; the species was also recognized in other samples, again quite close to the type. It differs from R. cladophora (Defl.) Below in the finer sutural ridges and the more distinctly cylindrical spines inserted on them.