Large trilobites in a stress-free Early Ordovician environment

Details

Ressource 1Download: Saleh et al. 2020 Large trilobites postprint.pdf (3064.75 [Ko])
State: Public
Version: Author's accepted manuscript
License: Not specified
Serval ID
serval:BIB_50241F2040B9
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Large trilobites in a stress-free Early Ordovician environment
Journal
Geological Magazine
Author(s)
Saleh Farid, Vidal Muriel, Laibl Lukáš, Sansjofre Pierre, Guériau Pierre, Perez Peris Francesc, Lustri Lorenzo, Lucas Victoire, Lefebvre Bertrand, Pittet Bernard, Daley Allison
Publication state
Published
Issued date
02/2021
Peer-reviewed
Oui
Volume
158
Number
2
Pages
261-270
Language
english
Abstract
Understanding variations in body size is essential for deciphering the response of an organism to its surrounding environmental conditions and its ecological adaptations. In modern environments, large marine animals are mostly found in cold waters. However, numerous parameters can influence body-size variations other than temperatures, such as oxygenation, nutrient availability, predation or physical disturbances by storms. Here, we investigate trilobite size variations in the Lower Ordovician Fezouata Shale deposited in a cold-water environment. Trilobite assemblages dominated by small- to normal-sized specimens that are a few centimetres in length are found in proximal and intermediate settings, while those comprising larger taxa more than 20 cm in length are found in the most distal environment of the Fezouata Shale. Drill core material from distal settings shows that sedimentary rocks hosting large trilobites preserved in situ are extensively bioturbated with a high diversity of trace fossils, indicating that oxygen and nutrients were available in this environment. In intermediate and shallow settings, bioturbation is less extensive and shallower in depth. The rarity of storm events (minimal physical disturbance) and the lack of predators in deep environments in comparison to shallower settings would also have helped trilobites attain larger body sizes. This highly resolved spatial study investigating the effects of numerous biotic and abiotic parameters on body size has wider implications for the understanding of size fluctuations over geological time.
Keywords
Palaeontology, Arthropod, body size, Palaeozoic, Fezouata Shale
Funding(s)
Swiss National Science Foundation / 205321_179084
Create date
19/01/2021 22:27
Last modification date
18/05/2024 6:59
Usage data