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Lejeunecysta oliva

Zonneveld, K.A.F. and Pospelova V. (2015). A determination key for modern dinoflagellate cysts. Palynology 39 (3), 387- 409.

 
dorsal view
SG-WRC-Bremen
Sample: GeoB xxxxx, Adriatic Sea
photos: Karin Zonneveld
cross section
ventral view

Field characteristics

Lejeunecysta oliva (Reid 1977) Turon et Londeix 1988

Field characteristics:
Pentagonal cysts in dorso-ventral view with two pointed, solid tipped antapical horns. Wall thin, surface smooth; thickened ridges marking a narrow excavated, circular cingulum. Archeopyle intercalary elongated posterior/anteriorly.

Motile affinity: Unknown.
Stratigraphic range: Upper Pleistocene-Recent.

Comparison with other species: 
This species can be recognised by the distinct reflection of a small cingulum, thickened wall at the apical horn and two antapical Horns. The cingulum is depressed. This species most closely resembles Lejeunecysta paratenella but has smooth rather than denticular cingular ridges. No spines, ridges or striae are present on the cyst wall.

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

Leipokatium invisitatum is a reare species that in the "Atlas" has been grouped with other cyst species with a brown cyst wall and a peridinioid form
Lejeunecysta oliva can be observed in temperate to subtropical coastal regions that are characterized by coastal upwelling and/or nutrient input by river discharge.
Distribution:
Lejeunecysta oliva is restricted to the coastal environments of temperate to subtropical regions in the eastern North and South Atlantic Oceans, the eastern North Pacific Ocean and the eastern South Indian Ocean. Exceptions are formed by a few recordings in the tropical upwelling region off NW Africa. It is present in upwelling or river discharge environments. Highest abundances (>2% and up to 9%) occur in the vicinity of the active upwelling cells off Senegal (NW Africa) and South Africa (SW Africa).

Environmental parameter range:
SST: 0 - 29.7°C (winter - summer) and summer SST: > 8.2°C. Exception is formed by a site in the northern Pacific Ocean where SST is below 0°C in winter. SSS: 26.8 - 37.5(summer - winter), [P]: 0.1 - 1.3 μmol/l, [N]: 0.04 - 10.4 μmol/l, chlorophyll-a: 0.13 - 21.7 ml/l, bottom water [O2]: 0 - 6.0 ml/l. Lejeunecysta oliva is characteristically present in upwelling regions where large inter-annual variability in the trophic state of the upper waters can occur with eutrophic conditions during active upwelling or when upwelling filaments cross the site and oligotrophic conditions otherwise. Furthermore it is present in regions influenced by (anthropogenic and natural) nutrient input by river discharge waters. High relative abundances occur where bottom waters are poorly ventilated although it is not absent from well ventilated sites.

Comparison with other records:
Without providing details (Radi and de Vernal, 2008) note this species to be present in Arctic environments.