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Impagidinium caspienense

Zonneveld, K.A.F. and Pospelova V. (2015). A determination key for modern dinoflagellate cysts. Palynology 39 (3), 387- 407.

 
dorsal view
cross section
ventral view
photographs from: Marret et al., 2004, Review of palaeobotany and Palynology, 129, 1 - 20.
scale bar 10 micron meter

Field Characteristics

Impagidinium caspiense Marret et al 2004

Field Characteristics:
Proximate cyst with subsherical to ellipsoidal ambitus containing an apical boss. Wall is finely granular and contains low intratabular linear relief. Tabulation is reflected by cavate septa with a prominent septum present between plate 1’’’’ and sulcus. The archeopyle is precingular (type 3P).

Dimensions: Central body length: 35 – 50 μm, body width: 30 – 43 μm.
Motile affinity: unknown
Stratigraphic range: Recent

Field characteristics:
I. caspiense is easily distinguishable from other Impagidinium species by its cavate septa. In this feature it resembles I. variaseptum. This latter species has a smooth cell wall whereas I. caspiense has low intratabular linear ridges. Furthermore I. caspiense has a distinct septa between 1’’’’ and the sulcus that can’t be found on I. variaseptum.

Geographic Distribution

Geographic distribution based on :
Zonneveld et al., 2013. Atlas of modern dinoflagellate cyst distribution based on 2405 datapoints. Review of Palaeobotany and Palynology, v. 191, 1-197
Impagidinium caspienense is endemic for the Caspian Sea and Aral Sea where oligotrophic conditions, low productivity, reduced salinities and well ventilated bottom waters are present.
Distribution:
Impagidinium caspienense is restricted to the Caspian Sea and Aral Sea where it can account for 73% of the association

Environmental parameters:
SST: 1.6 - 24.4°C (winter - summer). SSS: 8.5 - 13.3 (summer - winter), [P]: 0.10 - 0.13 μmol/l, [N]: 0.06 - 0.27 μmol/l, chlorophyll-a: 1.39 - 8.30 ml/l, bottom water [O2]: 6.2 - 6.7 ml/l.

Comparison with other records:
I. caspienense has not been recorded from regions not covered by this Atlas.