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A 104-Ma record of deep-sea Atelostomata (Holasteroida, Spatangoida, irregular echinoids) – a story of persistence, food availability and a big bang

Fossil deep-sea macrobenthos is scarce due to the rarity of onshore deep-sea sediments. Therefore, hypothesized migrations of shallow shelf taxa into the deep-sea after phases of mass extinction or oceanic anoxic events (onshore-offshore pattern) is not constrained by the fossil record. To resolve this conundrum, we investigated 1,475 deep-sea sediment samples (Atlantic, Pacific, Southern oceans; 200 - 4,700 m paleo-water depth). Ca. 41,500 spine fragments from Holasteroida and Spatangoida (Atelostomata) document a continuous occurrence of the groups since 104 Ma (late early Cretaceous). Literature records suggest even an older age (115 Ma). A gradual increase of spine tip morphotypes occurs since the Albian. An abrupt reduction in spine size and morphological inventory following the Cretaceous-Paleogene (K-Pg) Boundary Event is expression of a “Lilliput Effect”, related to nourishment depletion in the deep-sea. The post-event recovery lasted at least 5 Ma. Post-K-Pg Boundary Event assemblages seem to evolve progressively without any morphological breaks towards modern deep-sea assemblages. This observation is interpreted to result from in-situ evolution in the deep-sea and not from onshore-offshore migrations. The calculation of the “atelostomate spine accumulation rate” (ASAR) reveals low pre-Campanian values, possibly related to high remineralization rates of organic matter in the water column in the course of the mid-Cretaceous Thermal Maximum and its aftermath. A Maastrichtian cooling pulse marks the irreversible onset of fluctuating but generally higher atelostomate biomass that persists in the Cenozoic.

Details

Author
Frank Wiese1, Schlüter Nils2, Jessica Zirkel3, Jens O. Herrle3, Oliver Friedrich4
Institutionen
1Geowissenschaftliches Zentrum, Georg-August-Universität Göttingen, Germany; 2Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Humboldt-Universität zu Berlin, Germany; 3Institute of Geosciences, Goethe-University Frankfurt, Germany; 4Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Germany
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/n5ww-vt66