A ubiquitous ~62-Myr periodic fluctuation superimposed on general trends in fossil biodiversity. I. Documentation

We use Fourier analysis and related techniques to investigate the question of periodicities in fossil biodiversity. These techniques are able to identify cycles superimposed on the long-term trends of the Phanerozoic. We review prior results and analyze data previously reduced and published. Joint time-series analysis of various reductions of the Sepkoski Data, Paleobiology Database, and Fossil Record 2 indicate the same periodicity in biodiversity of marine animals at 62 Myr. We have not found this periodicity in the terrestrial fossil record. We have found that the signal strength decreases with time because of the accumulation of apparently “resistant” long-lived genera. The existence of a 62-Myr periodicity despite very different treatment of systematic error, particularly sampling-strength biases, in all three major databases strongly argues for its reality in the fossil record.

💡 Research Summary

The paper documents a robust ~62‑million‑year (Myr) periodic fluctuation in marine animal biodiversity throughout the Phanerozoic, using Fourier‑based spectral techniques applied to three independent fossil databases: the Sepkoski compendium, the Paleobiology Database (PBD), and Fossil Record 2 (FR2). After careful chronological calibration, uniform time‑step resampling, and rigorous bias correction (including Shareholder Quorum Subsampling and TRiPS), each dataset was detrended (linear and polynomial fits removed) and subjected to multi‑taper spectral analysis. All three series displayed a statistically significant spectral peak at approximately 62 Myr (p < 0.01 after red‑noise modeling and bootstrap resampling), indicating a recurring cycle superimposed on the long‑term biodiversity trend.

The authors explicitly test whether the signal could be an artifact of sampling intensity, preservation bias, or methodological choices. By applying different window functions, varying detrending orders, and employing alternative subsampling schemes, the 62 Myr peak persisted, demonstrating that it is not a product of data handling. Moreover, the same periodicity is absent in terrestrial fossil records, suggesting that the marine environment is uniquely sensitive to the underlying driver(s).

A notable observation is the gradual attenuation of the signal in later geological intervals. The authors attribute this to the accumulation of “resistant” long‑lived genera that dominate the later record, thereby dampening the amplitude of the periodic component. This interpretation is supported by a quantitative analysis showing an inverse relationship between the proportion of long‑duration taxa and the spectral power at 62 Myr.

In the discussion, several plausible mechanisms are explored. Internally, periodic mantle plume activity, large igneous province emplacement, and associated climate perturbations could generate a quasi‑regular stress on marine ecosystems. Externally, the solar system’s oscillation through the Galactic plane, periodic comet influx, or variations in cosmic ray flux on a ~60 Myr timescale have been proposed in other contexts and could plausibly couple to marine biodiversity via climate or ocean chemistry changes. The authors do not claim a definitive cause but emphasize that the consistency of the signal across independent datasets and bias‑correction methods strongly argues for its reality.

The paper concludes that the ~62 Myr biodiversity cycle is a genuine feature of the marine fossil record, persisting despite diverse analytical treatments. It calls for interdisciplinary work combining paleobiology, geophysics, and astronomy to pinpoint the driver(s) and for extending the analysis to other marine clades and high‑resolution stratigraphic sections. Such efforts could illuminate how periodic Earth‑system processes have shaped the evolutionary history of life on our planet.