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Cryodinium matsuokai

Cryodinium? matsuokai sp. nov., Uddandam et al. 2020

Holotype: Uddandam et al. 2020, Plate I; Fig, 1-4
Type locality: north-western Bay of Bengal, Recent sediments (0-1 cm)


Original description: Uddandam et al. 2020:

Diagnosis:
Small to intermediate protoperidinioid cyst with a peridinioid tabulation pattern fully reflected by high sutural septa (~10 μm). Spherical, proximate brown cyst with smooth
autophragm. Archeopyle intercalary presumably representing plate 2a. Operculum often adnate.

Description:
Small to intermediate protoperidinioid cysts.
Cyst body: Spherical in shape.
Autophragm: brown in colour, smooth to slightly granulated.
Paratabulation: fully reflected.
Paraplate: boundaries are expressed by high sutural septa (10-15 μm). Parasutural septa are thin (< 0.1 μm), hyline to light brown in colour with smooth to weakly serrate to denticulate margin.
Archeopyle: anterior intercalary in position involving middorsal paraplate (type 2a). Operculum: often adnate.

Dimensions:
Central cyst body: 30-35 μm, Cyst diameter: 42.5-45 μm, length of the parastural septa: 10-15 μm
5 specimens were measured

Comments:
The specimens of this species are often degraded or crumpled and operculum is often adnate hindering the clear conclusion of paratabulation and archeopyle involving one or two plates. Hence the assignment of Cryodinium is provisional. However, the paratbulation expression in the form of parasutural septa supports its assignment to Cryodinium.

Affinities/Comparison:
C?. matsuokai differs from C. meridianum in having high parasutural septa. C?. matsuokai is easily identified as it is the only spherical, brown protoperidinioid species with
fully expressed paratabulation.

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