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Palaeoperidinium nudum
Palaeoperidinium nudum Downie, 1957
Name not validly published: generic name not validly published until 1967.
Originally Palaeoperidinium (name not validly published), subsequently Pareodinia, thirdly Pareodinia?.
Taxonomic senior synonym: Pareodinia ceratophora, according to Wiggins (1975, p.103) and Kunz (1990, p.13). If validated, this name would be a junior homonym of Palaeoperidinium nudum Nagy, 1969.
Holotype: Downie, 1957, p.20, fig.11
Locus typicus: Dorset, England
Stratum typicum: Late Kimmeridgian
Original diagnosis: Downie, 1957, p.424
The test is ellipsoidal with a strong polar horn about one-, third of the total length. The tip of the horn is solid and faint striations occur at the base. A deep spiral groove is often present at the tip. A spiral equatorial furrow may be clearly or faintly seen in an entral position. No plates or longitudinal furrow are visible.
Dimensions of holotype: Length 105 µm; breadth 45 µm; length of horn 41 µm.
Affinities:
Downie, 1957, p. 424: This common species was associated with Gonyaulax, longicornis. In general appearance the species are much alike, the important differenee being the absence of armour in P. nudum. Some individuals belonging to G. Iongicornis would, on a casual examination, have been grouped with P. nudum. It is possible that P. nudum is a postecdysial form of G. Iongicornis, but a separate species has been created because intermediate forms are rare and the absence of armour is a striking feature.
Name not validly published: generic name not validly published until 1967.
Originally Palaeoperidinium (name not validly published), subsequently Pareodinia, thirdly Pareodinia?.
Taxonomic senior synonym: Pareodinia ceratophora, according to Wiggins (1975, p.103) and Kunz (1990, p.13). If validated, this name would be a junior homonym of Palaeoperidinium nudum Nagy, 1969.
Holotype: Downie, 1957, p.20, fig.11
Locus typicus: Dorset, England
Stratum typicum: Late Kimmeridgian
Original diagnosis: Downie, 1957, p.424
The test is ellipsoidal with a strong polar horn about one-, third of the total length. The tip of the horn is solid and faint striations occur at the base. A deep spiral groove is often present at the tip. A spiral equatorial furrow may be clearly or faintly seen in an entral position. No plates or longitudinal furrow are visible.
Dimensions of holotype: Length 105 µm; breadth 45 µm; length of horn 41 µm.
Affinities:
Downie, 1957, p. 424: This common species was associated with Gonyaulax, longicornis. In general appearance the species are much alike, the important differenee being the absence of armour in P. nudum. Some individuals belonging to G. Iongicornis would, on a casual examination, have been grouped with P. nudum. It is possible that P. nudum is a postecdysial form of G. Iongicornis, but a separate species has been created because intermediate forms are rare and the absence of armour is a striking feature.