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- Modern Dinocyst Key
- transparent cysts
- no septa, no processes
- Ataxodinium choane
Ataxodinium choane
Zonneveld, K.A.F. and Pospelova V. (2015). A determination key for modern dinoflagellate cysts. Palynology 39 (3), 387- 407.
dorsal view
sample: DP30PC Roman Warm Period
Gulf of Taranto
photographs: Karin Zonneveld
sample: DP30PC Roman Warm Period
Gulf of Taranto
photographs: Karin Zonneveld
cross section
ventral view
Field characteristics
Ataxiodinium choane Reid 1974
Field characteristics:
Spherical to subspherical cavate cyst, with a double cell wall. Periphragm characterised by a crenulate membrane connected to the endophragm by funnel-shaped depressions. Tabulation is only expressed by the precingular archeopyle (type P).
Dimensions: Cyst body diameter: 26- 37 µm (Reid, 1974).
Motile affinity: Probably a cyst of Gonyaulax spp.
Stratigraphic range: Lower Pleistocene-Recent.
Comparison with other species:
These cysts have a cell wall of two layers that are smooth without any ornamentation. The layers are connected to each other on several places but no tabulation is reflected. The size of the non-connected parts can vary. The cysts are quite robust and not often folded or broken. The archeopyle is most often beautifully visible.
Field characteristics:
Spherical to subspherical cavate cyst, with a double cell wall. Periphragm characterised by a crenulate membrane connected to the endophragm by funnel-shaped depressions. Tabulation is only expressed by the precingular archeopyle (type P).
Dimensions: Cyst body diameter: 26- 37 µm (Reid, 1974).
Motile affinity: Probably a cyst of Gonyaulax spp.
Stratigraphic range: Lower Pleistocene-Recent.
Comparison with other species:
These cysts have a cell wall of two layers that are smooth without any ornamentation. The layers are connected to each other on several places but no tabulation is reflected. The size of the non-connected parts can vary. The cysts are quite robust and not often folded or broken. The archeopyle is most often beautifully visible.
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
Zonneveld et al., 2013. Atlas of modern dinoflagellate cyst distribution based on 2405 datapoints. Review of Palaeobotany and Palynology, v. 191, 1-197
Ataxodinium choane is characteristically present in temperate to sub-polar, coastal to oceanic regions. It is observed in full marine environments and regions with reduced upper water salinities. It is restricted to sites with well-ventilated bottom waters where the upper waters are oligotrophic to eutrophic although highest relative abundances can be found in oligotrophic/mesotrophic environments.
Distribution:
A. choane accounts for up to 3% of the association and occurs in temperate and sub-polar regions of the Northern Hemisphere, notably south of the polar front. It is also reported from a few sites in the tropical upwelling areas of the Arabian Sea and the temperate South Atlantic Ocean. Highest abundances are observed in the central Mediterranean Sea and western part of the Black Sea. Although the species is observed regularly in coastal sites, it is not restricted to these regions. It is not recorded in areas with reduced upper water salinities such as river plumes.
Environmental parameter range:
SST: -2.0 - 28.4°C (winter - spring). SSS: 36.6 - 38.5 (summer - summer) with exception of two samples from the Black Sea where salinities vary between 17.5 -18.4 (summer - winter), [P]: 0.09 - 1.06 μmol/l, [N]: 0.15 - 9.86 μmol/l, chlorophyll-a: 0.09 - 20.9 ml/l, bottom water [O2]: 1.0 - 7.2 ml/l. A. choane has its highest abundances (>1%) in temperate regions with SST: between 1.2 - 10.0°C (winter - summer). The species is absent where SSS < 23.6 (summer) with exception of two sites from the Black Sea where SSS ranges between 17.5 -18.4 (summer - winter). Highest abundances occur in oligotrophic to mesotrophic environments with [P]: < 0.53 and [N]: < 1.86 μmol/l. The species is absent in regions where bottom waters are anoxic or hypoxic.
Comparison with other records:
Apart from observations given in this Atlas, A. choane has been observed in low amounts in the western Barents Sea where waters can be seasonally covered by sea ice (Solignac et al., 2009). It can be observed in areas with up to six months per year sea ice cover (de Vernal et al., 1998). However, the length of seasonal sea ice cover anti-correlates with the relative abundance of this species (Radi and de Vernal, 2008).
A. choane accounts for up to 3% of the association and occurs in temperate and sub-polar regions of the Northern Hemisphere, notably south of the polar front. It is also reported from a few sites in the tropical upwelling areas of the Arabian Sea and the temperate South Atlantic Ocean. Highest abundances are observed in the central Mediterranean Sea and western part of the Black Sea. Although the species is observed regularly in coastal sites, it is not restricted to these regions. It is not recorded in areas with reduced upper water salinities such as river plumes.
Environmental parameter range:
SST: -2.0 - 28.4°C (winter - spring). SSS: 36.6 - 38.5 (summer - summer) with exception of two samples from the Black Sea where salinities vary between 17.5 -18.4 (summer - winter), [P]: 0.09 - 1.06 μmol/l, [N]: 0.15 - 9.86 μmol/l, chlorophyll-a: 0.09 - 20.9 ml/l, bottom water [O2]: 1.0 - 7.2 ml/l. A. choane has its highest abundances (>1%) in temperate regions with SST: between 1.2 - 10.0°C (winter - summer). The species is absent where SSS < 23.6 (summer) with exception of two sites from the Black Sea where SSS ranges between 17.5 -18.4 (summer - winter). Highest abundances occur in oligotrophic to mesotrophic environments with [P]: < 0.53 and [N]: < 1.86 μmol/l. The species is absent in regions where bottom waters are anoxic or hypoxic.
Comparison with other records:
Apart from observations given in this Atlas, A. choane has been observed in low amounts in the western Barents Sea where waters can be seasonally covered by sea ice (Solignac et al., 2009). It can be observed in areas with up to six months per year sea ice cover (de Vernal et al., 1998). However, the length of seasonal sea ice cover anti-correlates with the relative abundance of this species (Radi and de Vernal, 2008).