Abstract
Molecular timescales estimate that early animal lineages diverged tens of millions of years before their earliest unequivocal fossil evidence. The Ediacaran macrobiota (~574 to 538 million years ago) are largely eschewed from this debate, primarily due to their extreme phylogenetic uncertainty, but remain germane. We characterize the development of Charnia masoni and establish the affinity of rangeomorphs, among the oldest and most enigmatic components of the Ediacaran macrobiota. We provide the first direct evidence for the internal interconnected nature of rangeomorphs and show that Charnia was constructed of repeated branches that derived successively from pre-existing branches. We find homology and rationalize morphogenesis between disparate rangeomorph taxa, before producing a phylogenetic analysis, resolving Charnia as a stem-eumetazoan and expanding the anatomical disparity of that group to include a long-extinct bodyplan. These data bring competing records of early animal evolution into closer agreement, reformulating our understanding of the evolutionary emergence of animal bodyplans.
| Original language | English |
|---|---|
| Journal | Science Advances |
| Volume | 7 |
| Issue number | 30 |
| DOIs | |
| Publication status | Published - 23 Jul 2021 |
Bibliographical note
Acknowledgments:We thank T. Davies for assistance with CT scanning, and F. Marone and E. Landon for assistance with SRXTM scanning. A. Kolesnikov, N. Bykova, D. Aleksandrov, O. Zharasbayev, J.-P. Duda, and D. Mel’nik are thanked for field assistance. E. G. Mitchell is thanked for advice and support with statistical analyses. We would like to thank the landowners for permitting access to sites in Charnwood Forest. We also thank A. Zhuravlev and one other anonymous reviewer for significantly improving the quality of our manuscript. Funding: F.S.D., A.G.L., and P.C.J.D. acknowledge support from the Natural Environment Research Council (NE/L002434/1 and NE/V010859/1 to F.S.D., NE/L011409/2 to A.G.L., and NE/N002067/1 to P.C.J.D.). F.S.D. is also funded by Merton College, Oxford, and the Royal Commission for the Exhibition of 1851. D.V.G. acknowledges support from the Russian Science Foundation (grants 17-17-01241 and 20-67-46028). P.C.J.D. is also funded by the Biotechnology and Biological Sciences Research Council (BB/N000919/1 and BB/T012773/1). P.C.J.D. and A.G.L. were funded by Natural Environment Research Council (NERC) grant (NE/P013678/1) part of the Biosphere Evolution, Transitions and Resilience (BETR) program, which is co-funded by the Natural Science Foundation of China (NSFC). Author contributions: F.S.D., A.G.L., P.R.W., and P.C.J.D. designed the study. D.V.G. and A.G.L. collected specimens from the White Sea, Russia. F.S.D. and A.G.L. conducted CT scans and F.S.D. and P.C.J.D. conducted synchrotron scans. F.S.D., P.V., J.F.-S., and E.G. segmented CT and synchrotron data. P.R.W. conducted SEM analyses. F.S.D. analyzed specimens and interpreted results, compiled the morphological matrix, and performed the phylogenetic analysis. F.S.D. wrote the initial draft of the manuscript with substantial input from A.G.L., P.R.W., P.C.J.D., and D.V.G. All authors approved the manuscript. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Data are available at the University of Bristol data repository, data.bris, at https://doi.org/10.5523/bris.mukcdnafukgq2n8oljgar1s23.