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Gonyaulacysta mosaicum
Gonyaulacysta mosaicum Downie, 1957, p.424, pl.20, fig.7; text-fig.2f ex Sarjeant, 1967b, p.253. Emendation: Sarjeant, 1976c, p.6–7, as Leptodinium mosaicum.
NOW Leptodinium?. Originally Palaeoperidinium (name not validly published), subsequently Gonyaulacysta, thirdly Leptodinium, fourthly (and now) Leptodinium?.
The name Palaeoperidinium mosaicum was not validly published in Downie (1957) since the generic name Palaeoperidinium was not validly published until 1967. Williams et al. (1998, p.253) accepted Sarjeant's (1967b) indirect reference to Downie (1957) as indication of a type (I.C.N. Article 40.3).
Holotype: Downie, 1957, pl.20, fig.7; text-fig.2f; Sarjeant, 1976c, pl.2, figs.3,5; text-figs.2a–b; Jan du Chêne et al., 1986a, pl.70, figs.5–6.
Age: late Kimmeridgian.
Original description (Downie, 1957)
Palaeoperidinium mosaicum sp. nov.
P1. XX, fig. 7 ; Text-fig. 2f
Diagnosis.--The ellipsoidal test is rigid and thick-walled. No process is present. The spiral equatorial furrow is central. Numerous small granular plates are present but not clearly arranged in belts. A longitudinal furrow is indicated by a belt of larger smoother plates.
Dimensions of holotype.--Length 50 microns; breadth 42 microns; depth 42 microns ; thickness of wall 1 micron.
Holotype.---Slide KL 11.32 (author's collection).
Locality of type.--No. 13.
Discussion.--This form differs considerably from any of the other dinoflagellates found, but the presence of the equatorial furrow indicates its affinity. The rigidity of the test, which is quite uncrushed, suggests
that it was originally partly mineralized. Any mineral matter originally present has, however, been removed by treatment with acid. In many ways it resembles Eodinia Eisenack 1936, but since it was impossible to determine whether the original wall was silico-organic, it could not be placed with any certainty in that genus.
NOW Leptodinium?. Originally Palaeoperidinium (name not validly published), subsequently Gonyaulacysta, thirdly Leptodinium, fourthly (and now) Leptodinium?.
The name Palaeoperidinium mosaicum was not validly published in Downie (1957) since the generic name Palaeoperidinium was not validly published until 1967. Williams et al. (1998, p.253) accepted Sarjeant's (1967b) indirect reference to Downie (1957) as indication of a type (I.C.N. Article 40.3).
Holotype: Downie, 1957, pl.20, fig.7; text-fig.2f; Sarjeant, 1976c, pl.2, figs.3,5; text-figs.2a–b; Jan du Chêne et al., 1986a, pl.70, figs.5–6.
Age: late Kimmeridgian.
Original description (Downie, 1957)
Palaeoperidinium mosaicum sp. nov.
P1. XX, fig. 7 ; Text-fig. 2f
Diagnosis.--The ellipsoidal test is rigid and thick-walled. No process is present. The spiral equatorial furrow is central. Numerous small granular plates are present but not clearly arranged in belts. A longitudinal furrow is indicated by a belt of larger smoother plates.
Dimensions of holotype.--Length 50 microns; breadth 42 microns; depth 42 microns ; thickness of wall 1 micron.
Holotype.---Slide KL 11.32 (author's collection).
Locality of type.--No. 13.
Discussion.--This form differs considerably from any of the other dinoflagellates found, but the presence of the equatorial furrow indicates its affinity. The rigidity of the test, which is quite uncrushed, suggests
that it was originally partly mineralized. Any mineral matter originally present has, however, been removed by treatment with acid. In many ways it resembles Eodinia Eisenack 1936, but since it was impossible to determine whether the original wall was silico-organic, it could not be placed with any certainty in that genus.