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Cryodinium meridianum

Cryodinium meridianum Esper and Zonneveld, 2001, p.37-38, text-fig.13; pl.3, figs.1-9.

This name was also proposed by Esper and Zonneveld (2002, p.202-203).

Holotype: Esper and Zonneveld, 2001, pl.3, figs.1-3; Esper and Zonneveld, 2002, pl.2, figs.4-6.
Age: Holocene.

Cryodinium meridianum gen. nov. sp. nov. (Fig. 13; Plate II, 4^9)
Holotype: GSUB M1, Sample PS2376-2/1 (England Finder coordinates K35/3).
Paratype : GSUB M2, Sample PS2366-1/4 (EFcoordinates U42/2).
Repository: Geosciences Collection of the University of Bremen.
Type location: The ACC at the APF, westward of the Greenwich Meridian.
Etymology: Latin, meridianus (southerly) in reference to the cyst discovery of this species in higher latitudes of the Southern Hemisphere around the Greenwich Meridian.

Diagnosis: Protoperidinioid cyst with a peridinioid tabulation pattern fully reflected by low sutures. Sphaeroidal, proximate, brown cyst comprised of an autophragm with scabrate texture. Tabulation pattern: 4P, 3a, 7Q, 3c, 5QP, 2QQ with an ortho-style ¢rst apical plate and a 2I archeopyle (1a and 2a) with a hexagonal 2a plate. Description: The strongly pigmented brown cysts are sphaeroidal in shape with a single layered, thin wall (V1 Wm). The wall surface is weakly to moderately scabrate with a paratabulation re£ected by sutures of low septa (1^1.5 Wm). Occasionally gentle folding is visible and appears to subdivide the paraplates. The intercalary archeopyle is formed by the separation of a single operculum consisting of two paraplates, which is sometimes attached but is usually absent.
Dimensions: Range in maximum diameter is 30 (39) 49 Wm. Sutures are 1^1.5 Wm high. Number of specimens measured is 8.
Remarks: The cysts are seldom well reserved. Most of the specimens are crushed, £attened or torn. The reflection of the paratabulation varies from prominent to nearly absent but the typical wall texture of this species is always present.
Discussion: ryodinium meridianum is related to the genus Protoperidinium, which includes the majority of modern peridiniinean species (Bujak and Davies, 1983), from its paratabulation pattern. Due to its three intercalary plates, C. eridianum would ¢t into the subgenus Protoperidinium (Bujak and Davies, 1983). C. meridianum is most likely produced by a Protoperidinium species with ortho-style 1P and hexa-style 2a paraplates.
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