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Confirm the identity of the first animals
The first complex organisms appeared during the Ediacarian period, about 600 million years ago. The taxonomic affiliation of many of these organizations has been difficult to discern. Fossils of DickinsoniaBilateral symmetry oval organisms were particularly difficult to classify. Bobrovskiy et al. performed an analysis using lipid biomarkers obtained from Dickinsonia fossils and found that the fossils contained almost exclusively cholesteroids, a marker found only in animals (see perspective by Summon and Erwin). So, Dickinsonia were basal animals. This supports the idea that Ediacaran's biota would have been a precursor to the explosion of animal forms observed later in the Cambrian, about 500 million years ago.
Science, this number p. 1246; see also p. 1198
Abstract
The enigmatic biota of Ediacara (571 million to 541 million years ago) represents the first macroscopic complex organisms in the geological record and could be the key to our understanding of the origin animals. The macrofossils of Ediacaran are as "strange as life on another planet" and have escaped the taxonomic classification, with interpretations ranging from marine animals or giant unicellular protists to terrestrial lichens. Here, we show that lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their phylogeny. Dickinsonia and his parents produced only cholesterolids, a characteristic of animals. Our results make these emblematic members of Ediacara 's biota the oldest confirmed macroscopic animals in the rock, indicating that the appearance of Ediacara' s biota was indeed a prelude to the Cambrian explosion. of animal life.
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