Challenges in reconstructing the vegetation associated with a late Eocene mammal fauna from Western Europe

Margaret E. Collinson, Jerry J. Hooker, Sharon J. Gibbons

Pages	107–124
DOI	10.37520/fi.2024.010
Keywords	Eocene, mammal, primate, plant mesofossils, resin, algal cyst, pollen, spore, seed, megaspore, microspore massulae, Azolla, Salvinia
Type of Article	Peer-reviewed
Citation	COLLINSON, Margaret E., HOOKER, Jerry J. a GIBBONS, Sharon J.. Challenges in reconstructing the vegetation associated with a late Eocene mammal fauna from Western Europe. Fossil Imprint / Acta Musei Nationalis Pragae, Series B – Historia Naturalis. Prague: National Museum, 2024, 80(1), 107–124. DOI: https://doi.org/10.37520/fi.2024.010. ISSN 2533-4050 (tisk), 2533-4069 (online). Also available from: https://www.nm.cz/en/periodicals/fossil-imprint-acta-musei-nationalis-pragae-series-b-historia-naturalis/80-1/challenges-in-reconstructing-the-vegetation-associated-with-a-late-eocene-mammal-fauna-from-western-europe

Fossil Imprint / Acta Musei Nationalis Pragae, Series B – Historia Naturalis | 2024/80/1

Bed TB33, a lacustrine unit within the late Eocene (early Priabonian) How Ledge Limestone, Headon Hill, Isle of Wight, UK, contains a rich mammalian fauna. The previously reconstructed food web included mammalian predators and prey (ground dwelling, scansorial and arboreal; insectivores, frugivores, herbivores and carnivores) and two inferred owls. Unfortunately, the extensive bulk sediment sampling and sieving used to obtain the vertebrate fauna had not yielded any plant fossils other than charophyte gyrogonites. This new work has focused on plant mesofossils and palynofacies in the uppermost horizons of the vertebrate-rich bed aiming to reconstruct the vegetation that hosted the mammals. Other than cysts of Zygnemataceae, phytoplankton are absent. The presence of the aquatic plants Azolla and Salvinia on the lake is documented by megaspores and microspore massulae. The palynomorphs are dominated by algal cysts, Azolla microspore massulae fragments and two morphologies of trilete fern spores. These data document a depositional setting in a lake with abundant free-floating Azolla or Salvinia and with a margin vegetation dominated by ferns. The data support one of our previous inferences that the arboreal mammals were brought to the site from some distance away by predators. However, the challenge to fully reconstruct the mammalian habitats remains.

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