Hornibrookina


Classification: ntax_cenozoic -> Isochrysidales -> Prinsiaceae -> Hornibrookina
Sister taxa: Futyania, Hornibrookina, Neobiscutum, Prinsius, Toweius

Daughter taxa (time control age-window is: 0-800Ma)
Hornibrookina edwardsii
Small to medium sized, normally-elliptical, central area narrow with ~8 pairs of lateral bars and a longitudinal bar.
Hornibrookina teuriensis
Medium sized, narrowly elliptical, central area broad with ~10 pairs of lateral bars and a longitudinal bar.
arched species
Hornibrookina arca
Medium sized (4-7µm), narrowly elliptical to lenticular, arched, central area with 7-11 pairs of lateral bars and a longitudinal bar.
Hornibrookina australis
Small to medium sized, narrowly elliptical to lenticular, arched, central area with 8-10 pairs of lateral bars.
small species
Hornibrookina weimerae
Small (2-3µm) species of Hornibrookina with somewhat rounded ends and a narrow central area filled by a central longitudinal bar. Individual transverse laths are impossible to discern with the light microscope. The proximal shield is relatively bright in XPL.
Hornibrookina apellanizii
Very small (2-3.5µm) Hornibrookina with a rhombohedral shape and a wide central area.
Hornibrookina sp.
Specimens which cannot be assigned to any established species

Taxonomy:

Citation: Hornibrookina Edwards, 1973
Rank: Genus
Type species: Hornibrookina teuriensis Edwards, 1973
Taxonomic discussion: Coccoliths may be arched and narrowly elliptical to lenticular. Six species have been described but they are all rather similar and possibly should be considered synonyms.

Distinguishing features: Elliptical placoliths with bicyclic distal shields with raised tube cycle and central area grill formed from robust bars.

Farinacci & Howe catalog pages: Hornibrookina *


Phylogenetic relations: Hornibrookina has long been tentatively placed in the Prinsiaceae (e.g. Perch-Neilsen 1985, Young & Bown 1997) but the coccoliths are atypical and the central structure looks to be disjunct from the rim so this assignment should be re-examined [JRY 2016]

Search data:
TagsLITHS: placolith, elliptical, CA: ca_disjunct, grill,
CSPH: equant, monomorphic,
MetricsLith size: 2->9µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Abundant in lower Paleocene high latitude settings and conspicuous around the PETM interval.
Last occurrence (top): in lower part of Ypresian Stage (22% up, 54.2Ma, in Ypresian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Danian Stage (0% up, 66Ma, in Danian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

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

Young, J. R. & Bown, P. R. (1997a). Cenozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 36-47. gs V O


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Hornibrookina compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-4-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=732 Go to Archive.is to create a permanent copy of this page - citation notes



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