During the Eocene, world climate experienced rapid and intense global warming, reaching a peak during the Palaeocene–Eocene Thermal Maximum (PETM), 56 my ago. The warmest global climate of the past 66 my occurred during the early Eocene epoch (about 56 to 48 mya) when megathermal floral elements, including palms, reached Antarctica. The increase in temperatures led to a rise in sea level, turning Europe into an archipelago. Data regarding the early Eocene herpetofaunas are scant, but the locality of Dormaal in Belgium represents one of the rare exceptions. The lizards consist of gekkotans, acrodontan and pleurodontan iguanians, anguimorphs such as glyptosaurines and the varanid Saniwa. These groups are believed to be thermophilic, and their appearance in this high latitude locality indicates that the tropics were expanded during this time. Some of these records also represent first appearances of these clades in Europe. Among them, a new iguanian taxon is represented by a unique tooth morphology – the teeth are bifurcated – indicating a specialization on trophic resources. However, because terrestrial ecosystems changed substantially during the Palaeogene, this might have caused higher extinction risk relative to generalists (e.g., the iguanian Geiseltaliellus). Understanding this geological epoch is relevant for present global climate change, including sea level rise, as well as the expansion of distribution of thermophilic taxa, including parasites that cause serious infectious diseases such as malaria.
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RBINS Staff Publications 2023
