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Evolution and taxonomy of the Paleogene calcareous nannofossil genus Hornibrookina

January 1, 2022

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.

Citation Information

Publication Year 2022
Title Evolution and taxonomy of the Paleogene calcareous nannofossil genus Hornibrookina
DOI 10.47894/mpal.68.1.04
Authors Jean Self-Trail, David K. Watkins, James J. Pospichal, Ellen Seefelt
Publication Type Article
Publication Subtype Journal Article
Series Title Micropaleontology
Index ID 70227186
Record Source USGS Publications Warehouse
USGS Organization Florence Bascom Geoscience Center