Evangelos Vlachos - Turtle species extinction across the Cretaceous/Palaeogene boundary

SCIMED - Geosciences - Turtle Evolution Symposium 2024

17:40, 1 July, English, 5 views

The last mass extinction event that took place some 66 million years ago at the Late Cretaceous/Palaeogene boundary caused the extinction of many clades, including the non-avian dinosaurs. Turtles, as well as several other vertebrate clades, survived. However, the debate about whether the diversity of turtles has been affected during this event is still ongoing. During the last two decades a huge amount of new data on the turtle fossil record has been published, accompanied by joint efforts to curate it together with previously published information in open databases like the PaleoBiology Database. This dataset now allows the construction of global diversity curves at the species level, which indicate that global turtle diversity not only was affected during the last mass extinction events at the end of the Cretaceous, but it was already in decline during the last 20 million years prior to the extinction event. Compared to the historical peak of turtle diversity in the Campanian, the global turtle diversity was reduced at half during the Danian, approximately, only to gradually recover during the Cenozoic. These results are different compared to previous analyses not only because they are based on a more updated dataset but also because previous estimations are based on generic counts, shown herein to add a significant and artificial taxonomic bias in vertebrate groups like turtles that contain multispecific genera. The sample coverage of turtle occurrences at the stage level is calculated and discussed as well.

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