Review
Version 1
Preserved in Portico This version is not peer-reviewed
The Fossil Record and Diversity of Pycnodondiform Fishes in Non-Marine Environments
Version 1
: Received: 19 March 2024 / Approved: 19 March 2024 / Online: 20 March 2024 (09:39:00 CET)
A peer-reviewed article of this Preprint also exists.
Cawley, J.J.; Kriwet, J. The Fossil Record and Diversity of Pycnodontiform Fishes in Non-Marine Environments. Diversity 2024, 16, 225. Cawley, J.J.; Kriwet, J. The Fossil Record and Diversity of Pycnodontiform Fishes in Non-Marine Environments. Diversity 2024, 16, 225.
Abstract
Pycnodont fishes were a successful clade of neopterygian fishes that are predominantly found from shallow marine deposits. However, throughout their long 180 million years reign (Late Triassic - end Eocene), they have made multiple incursions into both brackish and freshwater environments. This fossil record mostly consists of fragmentary dental material but articulated specimens are known from Early Cretaceous lacustrine localities in Spain. This review article aims to document all non-marine occurrences of Pycnodontiformes throughout most of the Mesozoic and early Palaeogene. This review highlights two interesting trends in the history of non-marine habitat colonization by pycnodonts: (1) a huge spike in non-marine occurrences during the Cretaceous, (2) the most occurrences in non-marine localities occurred at the latest Cretaceous, the Maastrichtian. The high number of colonization events within the Cretaceous lines up with extreme climatic events such as high temperatures resulting in high sea levels which regularly flooded continental masses, allowing pycnodonts easier access to non-marine habitats. The increased presence of pycnodonts in brackish and freshwater habitats during the Maastrichtian might have played a role in their survival through the K/Pg extinction event. Freshwater habitats are not as vulnerable as marine ecosystems to environmental disturbance as the base of their food chain relies on detritus. Pycnodonts might have used such environments as a refuge and began to occupy marine waters after the K/Pg extinction event.
Keywords
Pycnodonts, freshwater, brackish, Jurassic, Cretaceous, extinction, refuge.
Subject
Biology and Life Sciences, Ecology, Evolution, Behavior and Systematics
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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