Nannotax3 - ntax_cenozoic - Tribrachiatus orthostylus Nannotax3 - ntax_cenozoic - Tribrachiatus orthostylus

Tribrachiatus orthostylus

Classification: ntax_cenozoic -> Nannolith families inc sed -> Rhomboasteraceae -> Tribrachiatus -> Tribrachiatus orthostylus
Sister taxa: T. contortus, T. digitalis, T. orthostylus, T. absidatus, T. lunatus, T. sp.


Citation: Tribrachiatus orthostylus Shamrai, 1963
Rank: Species
Taxonomic discussion: The name T. orthostylus is "nom. subst. pro Discoaster tribrachiatus Bramlette & Riedel ; see ICBN Art. 55" according to Loeblich & Tappan 1966). This is probably because the combination Tribrachiatus tribrachiatus would have been a tautonym (both parts the same) which is not permitted under the ICBN. The type specimen and description of T. orthostylus is thus that of D. tribrachiatus.

Distinguishing features:
Parent taxon (Tribrachiatus): Solid nannoliths with three rays that typically have terminal bifurcations.
This taxon: Large, single-cycle tri-radiate nannoliths with little or no ray end bifurcation (<25% of the total arm length).

Farinacci & Howe catalog pages: T. orthostylus * , D. tribrachiatus * , D. rotans * , R. weii *

Search data:
LITHS: nannolith-radiate, star-shaped, CROSS-POLARS: 1ou, V-prominent,
Lith size: 8->13µm; Segments: 3->3;
Data source notes: lith size from OD & illustrated specimens
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP12 zone (50.5-53.7Ma, top in Ypresian stage). Data source: Perch-Nielsen 1985b
First occurrence (base): near top of NP10 zone (90% up, 54.3Ma, in Ypresian stage). Data source: Agnini et al. 2007 fig 8, 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. & Dunkley Jones, T. (2012). Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research. 32(2): 3-51. gs O

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 O

Bramlette, M. N. & Riedel, W. R. (1954). Stratigraphic value of discoasters and some other microfossils related to Recent coccolithophores. Journal of Paleontology. 28: 385-403. gs

Bramlette, M. N. & Sullivan, F. R. (1961). Coccolithophorids and related nannoplankton of the Early Tertiary in California. Micropaleontology. 7(2): 129-188. 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

Loeblich, A. R. & Tappan, H. (1966). Annotated index and bibliography of the calcareous nannoplankton. Phycologia. 5: 81-216. gs

Perch-Nielsen, K. (1967). Nannofossilien aus dem Eozan von Danemark. Eclogae Geologicae Helvetiae. 60: 19-32. gs O

Perch-Nielsen, K. (1971). Elektronenmikroskopische untersuchungen an Coccolithen und verwandten Formen aus dem Eozan von Danemark. Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab. 18(3): 1-76. gs O

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 - -. gs

Self-Trail, J. (2011). Paleogene Calcareous Nannofossils of the South Dover Bridge core, Southern Maryland (USA). Journal of Nannoplankton Research. 32(1): 1-28. gs

Self-Trail, J. M., Powars, D. S., Watkins, D. K. & Wandless, G. A. (2012). Calcareous nannofossil assemblage changes across the Paleocene–Eocene Thermal Maximum: Evidence from a shelf setting. Marine Micropaleontology. 92–93: 61-80. gs

Self-Trail, J., Seefelt, E. L., Shepherd, C. L. & Martin, V. A. (2017). Biostratigraphic and morphometric analyses of specimens from the calcareous nannofossil genus Tribrachiatus. Journal of Nannoplankton Research. 37(2-3): 177-188. gs

Shamrai, I. A. (1963). Nekotorye formy verkhnemelovykh i paleogenovykh kokkolitov i disko_asterov na yuge russkol platformy [Certain forms of Upper Cretaceous and Paleogene coccoliths and discoasters from the southern Russian Platform]. Izvestiya Vysshikh Uchebnykh Zavedeniy Geologiya i Razvedka. 6(4): 27-40. gs

Shepherd, C. L. & Kulhanek, D. K. (2016). Eocene nannofossil biostratigraphy of the mid-Waipara River section, Canterbury Basin, New Zealand. Journal of Nannoplankton Research. 36(1): 33-59. gs O

Steurbaut, E. (1990). Ypresian calcareous nannoplankton biostratigraphy and palaeogeography of the Belgian Basin. Bulletin de la Société Belge de Géologie. 97(1988): 251-285. gs

Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 200-224. gs

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 O


Tribrachiatus orthostylus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 2-12-2023

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