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The two phases of the Cambrian Explosion.
Sci Rep. 2018 11 09; 8(1):16656.SR

Abstract

The dynamics of how metazoan phyla appeared and evolved - known as the Cambrian Explosion - remains elusive. We present a quantitative analysis of the temporal distribution (based on occurrence data of fossil species sampled in each time interval) of lophotrochozoan skeletal species (n = 430) from the terminal Ediacaran to Cambrian Stage 5 (~545 - ~505 Million years ago (Ma)) of the Siberian Platform, Russia. We use morphological traits to distinguish between stem and crown groups. Possible skeletal stem group lophophorates, brachiopods, and molluscs (n = 354) appear in the terminal Ediacaran (~542 Ma) and diversify during the early Cambrian Terreneuvian and again in Stage 2, but were devastated during the early Cambrian Stage 4 Sinsk extinction event (~513 Ma) never to recover previous diversity. Inferred crown group brachiopod and mollusc species (n = 76) do not appear until the Fortunian, ~537 Ma, radiate in the early Cambrian Stage 3 (~522 Ma), and with minimal loss of diversity at the Sinsk Event, continued to diversify into the Ordovician. The Sinsk Event also removed other probable stem groups, such as archaeocyath sponges. Notably, this diversification starts before, and extends across the Ediacaran/Cambrian boundary and the Basal Cambrian Carbon Isotope Excursion (BACE) interval (~541 to ~540 Ma), ascribed to a possible global perturbation of the carbon cycle. We therefore propose two phases of the Cambrian Explosion separated by the Sinsk extinction event, the first dominated by stem groups of phyla from the late Ediacaran, ~542 Ma, to early Cambrian stage 4, ~513 Ma, and the second marked by radiating bilaterian crown group species of phyla from ~513 Ma and extending to the Ordovician Radiation.

Authors+Show Affiliations

Department of Biological Evolution, Faculty of Biology, Moscow State University named after M.V. Lomonosov, Moscow GSP-1, 119991, Russia.School of GeoSciences, University of Edinburgh, King's Buildings, James Hutton Road, Edinburgh, EH9 3FE, UK. Rachel.Wood@ed.ac.uk.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30413739

Citation

Zhuravlev, Andrey Yu, and Rachel A. Wood. "The Two Phases of the Cambrian Explosion." Scientific Reports, vol. 8, no. 1, 2018, p. 16656.
Zhuravlev AY, Wood RA. The two phases of the Cambrian Explosion. Sci Rep. 2018;8(1):16656.
Zhuravlev, A. Y., & Wood, R. A. (2018). The two phases of the Cambrian Explosion. Scientific Reports, 8(1), 16656. https://doi.org/10.1038/s41598-018-34962-y
Zhuravlev AY, Wood RA. The Two Phases of the Cambrian Explosion. Sci Rep. 2018 11 9;8(1):16656. PubMed PMID: 30413739.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The two phases of the Cambrian Explosion. AU - Zhuravlev,Andrey Yu, AU - Wood,Rachel A, Y1 - 2018/11/09/ PY - 2018/07/18/received PY - 2018/10/24/accepted PY - 2018/11/11/entrez PY - 2018/11/11/pubmed PY - 2019/12/18/medline SP - 16656 EP - 16656 JF - Scientific reports JO - Sci Rep VL - 8 IS - 1 N2 - The dynamics of how metazoan phyla appeared and evolved - known as the Cambrian Explosion - remains elusive. We present a quantitative analysis of the temporal distribution (based on occurrence data of fossil species sampled in each time interval) of lophotrochozoan skeletal species (n = 430) from the terminal Ediacaran to Cambrian Stage 5 (~545 - ~505 Million years ago (Ma)) of the Siberian Platform, Russia. We use morphological traits to distinguish between stem and crown groups. Possible skeletal stem group lophophorates, brachiopods, and molluscs (n = 354) appear in the terminal Ediacaran (~542 Ma) and diversify during the early Cambrian Terreneuvian and again in Stage 2, but were devastated during the early Cambrian Stage 4 Sinsk extinction event (~513 Ma) never to recover previous diversity. Inferred crown group brachiopod and mollusc species (n = 76) do not appear until the Fortunian, ~537 Ma, radiate in the early Cambrian Stage 3 (~522 Ma), and with minimal loss of diversity at the Sinsk Event, continued to diversify into the Ordovician. The Sinsk Event also removed other probable stem groups, such as archaeocyath sponges. Notably, this diversification starts before, and extends across the Ediacaran/Cambrian boundary and the Basal Cambrian Carbon Isotope Excursion (BACE) interval (~541 to ~540 Ma), ascribed to a possible global perturbation of the carbon cycle. We therefore propose two phases of the Cambrian Explosion separated by the Sinsk extinction event, the first dominated by stem groups of phyla from the late Ediacaran, ~542 Ma, to early Cambrian stage 4, ~513 Ma, and the second marked by radiating bilaterian crown group species of phyla from ~513 Ma and extending to the Ordovician Radiation. SN - 2045-2322 UR - https://www.unboundmedicine.com/medline/citation/30413739/The_two_phases_of_the_Cambrian_Explosion_ L2 - https://doi.org/10.1038/s41598-018-34962-y DB - PRIME DP - Unbound Medicine ER -