Evolution and taxonomy of the Paleogene calcareous nannofossil genus Hornibrookina

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The genus Hornibrookina consists of enigmatic calcareous nannofossils that first appeared shortly after the K-Pg mass extinction. Due to their relative paucity in most published sections, specimens of this genus have not been previously studied in detail and their paleobiogeographic preferences and evolutionary history have been poorly understood. Biostratigraphic and morphometric analyses of Hornibrookina specimens from outcrops and cores from the Atlantic Ocean, the North Sea, the Southern Ocean, the Indian Ocean, North America, South America, Africa, and New Zealand resulted in a comprehensive and detailed documentation of this group of calcareous nannofossils. Biostratigraphic ranges for each species are refined and a hypothetical evolutionary lineage for this genus is proposed. Two new species (Hornibrookina gracila and Hornibrookina indistincta), two new combinations (Hornibrookina elegans and Hornibrookina australis arca) and one new subspecies (Hornibrookina australis australis) are described. Morphometric analyses prove that Hornibrookina edwardsii and Hornibrookina teuriensis are distinctly different species with biostratigraphically useful ranges. Hornibrookina apellanizii is shown to be invalid.

Publication type Article
Publication Subtype Journal Article
Title Evolution and taxonomy of the Paleogene calcareous nannofossil genus Hornibrookina
Series title Micropaleontology
DOI 10.47894/mpal.68.1.04
Volume 68
Issue 1
Year Published 2022
Language English
Publisher Micropaleontology Press
Contributing office(s) Florence Bascom Geoscience Center
Description 29 p.
First page 85
Last page 113
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