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Ediacaran Origin and Ediacaran-Cambrian Diversification of Metazoa

Overview
Journal Sci Adv
Specialties Biology
Science
Date 2024 Nov 13
PMID 39536100
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Abstract

The timescale of animal diversification has been a focus of debate over how evolutionary history should be calibrated to geologic time. Molecular clock analyses have invariably estimated a Cryogenian or Tonian origin of animals while unequivocal animal fossils first occur in the Ediacaran. However, redating of key Ediacaran biotas and the discovery of several Ediacaran crown-Metazoa prompt recalibration of molecular clock analyses. We present revised fossil calibrations and use them in molecular clock analyses estimating the timescale of metazoan evolutionary history. Integrating across uncertainties including phylogenetic relationships, clock model, and calibration strategy, we estimate Metazoa to have originated in the early Ediacaran, Eumetazoa in the middle Ediacaran, and Bilateria in the upper Ediacaran, with many crown-phyla originating across the Ediacaran-Cambrian interval or elsewise fully within the Cambrian. These results are in much closer accord with the fossil record, coinciding with marine oxygenation, but they reject a literal reading of the fossil record.

References
1.
Zhuravlev A, Wood R, Penny A . Ediacaran skeletal metazoan interpreted as a lophophorate. Proc Biol Sci. 2015; 282(1818):20151860. PMC: 4650157. DOI: 10.1098/rspb.2015.1860. View

2.
Zhang X, Siveter D, Waloszek D, Maas A . An epipodite-bearing crown-group crustacean from the Lower Cambrian. Nature. 2007; 449(7162):595-8. DOI: 10.1038/nature06138. View

3.
Antcliffe J, Callow R, Brasier M . Giving the early fossil record of sponges a squeeze. Biol Rev Camb Philos Soc. 2014; 89(4):972-1004. DOI: 10.1111/brv.12090. View

4.
. On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. Br Foreign Med Chir Rev. 2018; 25(50):367-404. PMC: 5184128. View

5.
Dohrmann M, Worheide G . Dating early animal evolution using phylogenomic data. Sci Rep. 2017; 7(1):3599. PMC: 5472626. DOI: 10.1038/s41598-017-03791-w. View