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Spiniferites bentorii

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

 
dorsal view
photographs: Karin Zonneveld
ventral view
 

Field characteristics

Spiniferites bentorii (Rossignol 1964) Wall et Dale 1970

Field characteristics:
Proximochorate ovoid to pear-–shaped cysts with a pronounced apical protuberance. The cysts have a relative thick (1-2 µm) microgranulate wall. Tabulation is expressed by low sutural septa formed between gonal and occasionally intergonal processes. When fully formed, processes are slender and delicate with bifurcating tips. Otherwise, processes are usually short and stumpy. Archeopyle is precingular (type P), reduced and six sided with rounded corners.

Dimensions Spiniferites bentorii: Cyst body: 45 to 63 µm (width) to 60 to 73 µm (length); length of processes: 15 to 25 µm, but can be reduced.
Motile affinity: Gonyaulax digitale (Pouchet 1883) Kofoid 1911
Cyst-theca relationship: Wall, 1965
Stratigraphic range: Upper Miocene to Recent.

Comparison with other species:
S. bentorii is among the more difficult species to recognise. The combination of an apical nodge and the pear shape form the differentiating criteria. The specimens with reduced processes are the easiest to recognise. It differs from Spinferites belerius in its size.

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
Spiniferites bentorii has a temperate to equatorial mainly coastal distribution. It is not observed in this Atlas with salinities below 27.5. Highest relative abundances occur in mesotrophic to eutrophic environments.
Distribution:
The distribution of Spiniferites bentorii is restricted to temperate to equatorial coastal regions. It is absent from the central part of the Oceans with exception of one recording in the central North Atlantic. Highest abundances (up to 28%) occur in eutrophic regions of the Yellow Sea and the East China Sea. It has not been observed where nitrate concentrations in the surface waters are low.

Environmental parameter range:
SST: 0.02 - 29.8°C (winter - spring) with summer SST > 11.2°C. SSS: 27.5 - 39.4 (spring - autumn),[P]: 0.06 - 1.06 μmol/l, [N]: 0.1 - 9.3 μmol/l, chlorophyll-a: 0.1 - 14.7 ml/l, bottom water [O2]: 0 - 6.3 ml/l.
Although Spiniferites bentorii can be abundant in oligotrophic regions, highest abundances occur in (seasonally) mesotrophic to eutrophic settings such as upwelling areas, where large inter-annual variability in the trophic state of the upper waters can occur.

Comparison with other records:
Apart from the records in the dataset of this Atlas, Spiniferites bentorii has been observed in surface sediments of coastal sites of the Gulf of Oman, southeastern Black Sea, the Marmara Sea (Bradford, 1975; Mudie et al., 2001; 2004), the South China Sea and coastal regions off southwestern Australia (Marret and Zonneveld, 2003) and the Bahía Blanca estuary (Argentinia, Grill and Guerstein, 1995; Borel et al., 2006). In the Gulf of Oman it occurs under hypersaline conditions with salinities > 40.
In sediment trap studies it is only registered as a separate species in the Saanich Inlet (B.C. Canada) where its production appears to anticorrelate to discharge of the Fraser River, SST: and solar insolation (Price and Pospelova, 2011).