Nannotax3 - ntax_cenozoic - Hornibrookina teuriensis

Citation: Hornibrookina teuriensis Edwards, 1973

Variants: The species H. edwardsii Perch-Nielsen 1977 and H. teuriensis Edwards 1973 are very similar and differentiation of them has been inconsistent. Self-Trail et al. 2022 carried out a detailed morphometric study and concluded that the two species could be distinguished, but belonged to the same anagenetic lineage, with H. edwardsii representing forms with a smaller central area and H. teuriensis forms with a larger central area. On this basis the populations in NP1 consist exclusively of H. edwardsii whilst subsequent populations consist of an intergrading mixure of H. teuriensis and H. edwardsii. In low diversity Early Palaeocene populations from the Southern Ocean this differentiation may be useful, for other purposes it is simpler to regard H. edwardsii as a variant of H. teuriensis.

Taxonomic discussion: Inconpicuous (small and dark) in XPL but can be abundant in Danian assemblages.

Distinguishing features:
Parent taxon (Hornibrookina): Elliptical placoliths with bicyclic distal shields with raised tube cycle and central area grill formed from robust bars.
This taxon: Medium to large (5-10 µm) elliptical; central area with ~10 pairs of lateral bars, and a longitudinal bar, sometimes over-calcified; R units often form ring of nodes around central area

An exclusively southern ocean form according to Self-Trail et al. 2022. It can dominate assemblages (Pospichal & Wise 1990, Pospichal 1996, Arney & Wise 2002)

Geological Range:
Notes: Varol, (1989, fig. 12.4) recorded a useful LAD in the middle of NP5.
according to Self-Trail et al. 2022 the FAD of H. teuriensis (sensu stricto) with a wide central area is in NP3 whist only variants with a small central area (H. edwardsii) occur in NP2.
Last occurrence (top): in mid part of NP8 zone (50% up, 58Ma, in Thanetian stage). Data source: Self-Trail et al. 2022
First occurrence (base): within NP1 zone (65.47-66.04Ma, base in Danian stage). Data source: Perch-Nielsen 1985

References:

Arney, J. E. & Wise, S. W. (2003). Paleocene–Eocene nannofossil biostratigraphy of ODP Leg 183, Kerguelen Plateau. Proceedings of the Ocean Drilling Program, Scientific Results. 183: 1-59. gs

Bown, P. R., Kim, H. & Gibbs, S. J. (2023). Danian calcareous nannofossil evolution and taxonomy with focus on sites from the North Atlantic Ocean (IODP Expedition 342, Sites U1403 and U1407). Journal of Nannoplankton Research. 41(2): 110-157. gs O

Edwards, A. R. (1973b). Key species of New Zealand calcareous nannofossils. New Zealand Journal of Geology and Geophysics. 16: 68-89. gs

Perch-Nielsen, K. (1977). 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 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 (1): 427-555. gs

Pospichal, J. J. & Wise, S. W. (1990). Maestrichtian calcareous nannofossil biostratigraphy of Maud Rise ODP leg 113 sites 689 and 690, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 465-487. 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

Pospichal, J. J. (1996). High latitude calcareous nannofossil changes at the Cretaceous/Tertiary boundary in the southern Indian Ocean. In, Moguilevsky, A. & Whatley, R. (eds) Microfossils and Oceanic Environments. University of Wales, Aberystwyth-Press 205-229. gs

Self-Trail, J. M., Watkins, D. K., Pospichal, J. J. & Seefelt, E. L. (2022). Evolution and taxonomy of the Paleogene calcareous nannofossil genus Hornibrookina. Micropaleontology. 68(1): 85-113. gs

Varol, O. (1989c). Palaeocene calcareous nannofossil biostratigraphy. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series . 265-310. gs

Hornibrookina teuriensis

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Sub-taxa & variants (time control age-window is: 0-800Ma)
				Hornibrookina edwardsii Variant of H. teuriensis with smaller central area