Reconstructed setting· The columns of time

Paleozoic world

539 Ma → 252 Ma

A shallow reef, and land that starts bare and ends forested. Nine separate published claims govern this scene, more than any other backdrop, because few eras change so completely from one end to the other.

What the evidence shows

The reef is drawn because the Devonian hosted the largest metazoan reef ecosystem in Earth history. The land is bare in the older part because Cambrian landscapes were dominated by mobile rivers in the absence of significant vegetation, a sedimentological argument rather than a botanical one: with no roots to hold the banks, rivers wander. Between 419 and 393 million years the vegetation is low and treeless, because in the Lower Devonian trees did not yet exist. None of the three is an illustrator's invention: each is published, and the backdrop follows all nine of them one by one.

Bounds and conventions

No backdrop here rests on more evidence, and it is still a composite: a Devonian reef, a bare Cambrian floodplain and a Carboniferous forest never stood together. What is drawn is a sequence of scenes that change with the zoom, not a landscape anyone could have visited.

Sources

1. Qie, W. et al. (2019), Palaeobiodiversity and Palaeoenvironments
2. Buatois, L. et al. (2022), Integrative and Comparative Biology
3. Stacey, J. et al. (2024), Geology
4. Gensel, P. et al. (2020)
5. Retallack, G. (2015), Journal of the Geological Society
6. Stein, W. et al. (2007), Nature
7. Davies, N. S. et al. (2024), Journal of the Geological Society
8. Stein, W. et al. (2019), Current Biology
9. Cascales-Miñana, B. et al. (2016), Historical Biology
10. Mishra, S. et al. (2018), Palaeobiodiversity and Palaeoenvironments
11. White, J. et al. (2020), American Journal of Science