Taxonomy:
Distinguishing features: large (>9μm), circular with wide central area;
Farinacci & Howe catalog pages: C. robustus *
Morphology: Bown (2016) reccomends restricting E. robusta to forms >9 µm in size, with smaller forms being placed in E. aliquanta (5-9 µm) or E. orbis (< 5 µm). Only the smallest forms (E. orbis) continue into the Eocene (Bown & Dunkley Jones 2012).
Tags | LITHS: placolith, circular, CA: vacant, CSPH: equant, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
Metrics | Lith size: 6->12µm; Data source notes: lith size from Romein 1979 reduced minimum from Bown & Dunkley Jones 2012 |
Geological Range:
Notes: Romein (1979) gave a range of NP8 to mid NP9 and thishas been supported by e.g .Raffi et al. (2005) and Agnini et al. 2007), fig. 9 suggest a range of upper NP8 (ca 85% up) to lower NP9 (ca 20% up). Other authors (e.g. Bown & Dunkley Jones, 2012), have quoted much wider ranges, however, this was based on small specimens now placed in E. orbis. If the species is restricted to large forms then it does have an NP8-9 range. [Bown 2016]
Last occurrence (top): in lower part of NP9 zone (20% up, 56.9Ma, in Ypresian stage). Data source: Agnini et al. 2007 - fig 9
First occurrence (base): near top of NP8 zone (85% up, 57.4Ma, in Thanetian stage). Data source: Agnini et al. 2007, fig 9
Plot of occurrence data:
Agnini, C., Fornaciari, E., Raffi, I., Rio, D., Rohl, U. & Westerhold, T. (2007a). High-resolution nannofossil biochronology of middle Paleocene to early Eocene at ODP Site 1262: Implications for calcareous nannoplankton evolution. Marine Micropaleontology. 64: 215-248. gs Bown, P. R. (2005d). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research. 27(1): 21-95. gs V O Bown, P. R. (2010). Calcareous nannofossils from the Paleocene/Eocene Thermal Maximum interval of southern Tanzania (TDP Site 14). Journal of Nannoplankton Research. 31(1): 11-38. gs V O Bown, P. R. (2016). Paleocene calcareous nannofossils from Tanzania (TDP sites 19, 27 and 38). Journal of Nannoplankton Research. 36(1): 1-32. gs V O Bown, P. R., Dunkley-Jones, T. & Young, J. R. (2007). Umbilicosphaera jordanii Bown 2005 from the Paleogene of Tanzania: confirmation of generic assignment and a Paleocene origination for the family Calcidiscaceae. Journal of Nannoplankton Research. 29(1): 25-30. gs V O Bramlette, M. N. & Sullivan, F. R. (1961). Coccolithophorids and related nannoplankton of the Early Tertiary in California. Micropaleontology. 7(2): 129-188. gs Edwards, A. R. & Perch-Nielsen, K. (1975). Calcareous nannofossils from the southern Southwest Pacific, Deep Sea Drilling Project, Leg 29. Initial Reports of the Deep Sea Drilling Project. 29: 469-539. gs V O Müller, C. (1974b). Calcareous nannoplankton, Leg 25 (Western Indian Ocean). Initial Reports of the Deep Sea Drilling Project. 25: 579-633. gs V O Okada, H. & Thierstein, H. R. (1979). Calcareous nannoplankton - Leg 43, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 43: 507-573. gs V O Perch-Nielsen, K. (1977a). Albian to Pleistocene calcareous nannofossils from the Western South Atlantic, DSDP Leg 39. Initial Reports of the Deep Sea Drilling Project. 39: 699-823. gs V O Raffi, I., Backman, J. & Palike, H. (2005). Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the Paleo-equatorial Pacific Ocean. Palaeogeography Palaeoclimatology Palaeoecology. 226: 93-126. gs Romein, A. J. T. (1979). Lineages in Early Paleogene calcareous nannoplankton. Utrecht Micropaleontological Bulletin. 22: 1-231. gs V O Wise, S. W. & Wind, F. H. (1977). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project. 36(269-491): -. gs V OReferences:
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Ericsonia robusta compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-1-2021
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