Bark Beetles Outdate the Flowers: A Fossil-Fueled Revision of Evolutionary Timelines
A new study challenges long-held assumptions about the evolutionary origins of bark beetles (Scolytinae) by rigorously testing the placement of a key fossil, †Cylindrobrotus pectinatus. Using total-evidence dating that integrates molecular data, morphology, and 19 fossils, researchers found this specimen belongs within the beetle subfamily rather than at its stem, invalidating its previous use as a sole calibration point. Comparing multiple dating methods—including node dating and a fossil-only Bayesian Brownian Bridge model—the team consistently estimated the group’s diversification between approximately 150 and 134 million years ago. This timeline places the origin of bark beetles firmly before the Angiosperm Terrestrial Revolution, suggesting their early evolution was not initially driven by flowering plants.
Why it might matter to you: This research is a masterclass in methodological rigor for divergence time estimation, directly relevant to your work in phylogenetics and macroevolution. It underscores the critical impact of fossil placement on molecular dating and demonstrates how integrating multiple analytical approaches can yield more reliable estimates of speciation events. For anyone reconstructing evolutionary trees or studying coevolutionary histories, these findings highlight the necessity of questioning single calibration points and advocate for a more robust, multi-method framework to trace common ancestry.
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