Predation is one of the most fundamental ecological and evolutionary drivers in modern and ancient ecosystems. Here, we report the discovery of evidence of the oldest scavenging of shallowly buried bodies of iconic soft-bodied members of the Ediacara Biota by cryptic seafloor mat-burrowing animals that produced the furrow and levee trace fossil, Helminthoidichnites isp. These mat-burrowers were probably omnivorous, stem-group bilaterians that largely grazed on microbial mats but when following mats under thin sands, they actively scavenged buried Dickinsonia, Aspidella, Funisia and other elements of the Ediacara Biota. These traces of opportunistic scavengers of dead animals from the Ediacaran of South Australia represent a fundamental ecological innovation and a possible pathway to the evolution of macrophagous predation in the Cambrian. While the Ediacaran oceans may have had oxygen levels too low to support typical large predators, the Helminthoidichnites maker lived in and grazed on microbial mats, which may have provided a localized source of oxygen.
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Cover Image
Cover Image
Gently inclined strata of the upper Bylot Supergroup in Edwin Inlet, Baffin Island (Canada). Bangiomorpha pubescens, a fossil red alga and the oldest taxonomically resolved eukaryote, occurs in the Bylot Supergroup and equivalent rocks in northeastern Canada. Recent radiometric dating has tightly constrained the first appearance of this fossil to ca. 1045 million years ago. Image kindly provided by Galen Halverson (McGill University), who with his co-authors in this issue, reviews the methods by which the Proterozoic time scale is dated and provide an up-to-date compilation of age constraints on key fossil first and last appearances, geological events, and horizons during the Tonian and Cryogenian periods. Their article also develops a new age model for a ca. 819–740 Ma composite section in Svalbard. For details, see pages 137–147.
Ediacaran scavenging as a prelude to predation
Timothy W. Lyons, Mary L. Droser, Kimberly V. Lau, Susannah M. Porter, James G. Gehling, Mary L. Droser; Ediacaran scavenging as a prelude to predation. Emerg Top Life Sci 28 September 2018; 2 (2): 213–222. doi: https://doi.org/10.1042/ETLS20170166
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