Nannotax3 - ntax_cenozoic - Tribrachiatus contortus

Citation: Tribrachiatus contortus (Stradner, 1958) Bukry, 1972

Basionym: Discoaster contortus Stradner, 1958

Synonyms:

Rhomboaster contortus (Stradner, 1958) Bybell & Self-Trail 1995

Distinguishing features:
Parent taxon (Tribrachiatus): Solid nannoliths with three rays that typically have terminal bifurcations.
This taxon: Tri-radiate forms with long ray tip bifurcations that deviate strongly from the plane of the nannolith, giving the appearance of two asymmetrically offset and superimposed tri-radiate cycles.

Geological Range:
Last occurrence (top): at top of NP10 zone (100% up, 54.2Ma, in Ypresian stage). Data source: Agnini et al. 2007 fig 8, 9; zonal marker (Perch-Nielsen 1985)
First occurrence (base): in upper part of NP10 zone (65% up, 54.8Ma, in Ypresian stage). Data source: Agnini et al. 2007 fig 8, 9

References:

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

Bukry, D. (1972b). Further comments on coccolith stratigraphy, Leg 12 Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 12: 1071-1083. gs

Bybell, L. M. & Self-Trail, J. (1995). Evolutionary, biostratigraphic and taxonomic study of calcareous nanofossils from a continuous Palaeocene-Eocene boundary section in New Jersey. U.S. Geological Survey, Professional Paper. 1554: 1-36. gs O

Bybell, L. & Self-Trail, J. (1997). Late Paleocene and Early Eocene calcareous nannofossils from three boreholes in an onshore-offshore transect from New Jersey to the Atlantic continental rise. Proceedings of the Ocean Drilling Program, Scientific Results. 150: 91-110. gs O

MacKenzie, D. T. & Wise,S. W. (1983). Paleocene and Eocene calcareous nannofossils from Deep Sea Drilling Project Legs 25 and 40, South and East of Africa. Initial Reports of the Deep Sea Drilling Project. 71(2): 1141-1170. gs

Perch-Nielsen, K. (1985). Cenozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs

Perch-Nielsen, K., Sadek, A., Barakat, M. G. & Teleb, F. (1978). Late Cretaceous and Early Tertiary Calcareous nannofossil and Planktonic foraminifera zones from Egypt. Actes du VI Colloque Africain de Micropaléontologie - Tunis 1974. Annales des Mines et de la Géologie Tunis. 28: 337-403. gs

Pospichal, J. J. & Wise, S. W. (1990). Paleocene to Middle Eocene calcareous nannofossils of ODP sites 689 and 690, Maud Rise, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 613-638. gs

Salomon, R. (1999). The Calcite Palace. Website - https://ina.tmsoc.org/galleries/CalcitePalace/index.htm. -. gs

Stradner, H. (1958). Die fossilen Discoasteriden Osterreichs. I. Erdoel-Zeitschrift. 74(6): 178-188. gs

Tribrachiatus contortus

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