Oldest sponges found, according to ScienceDaily 15 October 2018 and Nature Ecology & Evolution 15 October 2018; doi: 10.1038/s41559-018-0676-2.
Researchers at the University of California have found evidence of sponges in rock and oils from Oman, Siberia, and India, dated as 660-635 million years ago. This is classified the Neoproterozoic Era, and is claimed to be 100 million years before the Cambrian explosion of animal life. The researchers were looking for “biomarkers” – chemicals that are distinctive to particular living things. They found a steroid compound named 26-methylstigmastane (26-mes), which has a unique structure currently only known to be produced by a kind of sponge, named demosponges.
Alex Zumberge, who was involved in the study, explained: “This steroid biomarker is the first evidence that demosponges, and hence multicellular animals, were thriving in ancient seas at least as far back as 635 million years ago.”
Editorial Comment: The reason we know this substance is only produced by demosponges is that demosponges are alive and well and living on the sea floors now. If these steroids did come from ancient demosponges these scientists have simply found evidence that demosponges have always been demosponges, and they have multiplied after their kind.
This is not the first time that steroids found in rocks and oils have been used to claim extremely old dates for fossilised animals. However, before such claims can be made the researchers need to know how long steroids can survive in the conditions represented by rocks and sediments. We challenge palaeontologists to team up with organic chemists and actually do some experiments that test the decay rates of steroids and any other organic molecules found in fossils. We predict the answer will be a lot shorter than 635 million years.
Photo of purple demosponge: James St John, reproduced under Creative Commons Licence (CC BY 2.0)
Evidence News vol. 18 No. 15
31 October 2018
Creation Research Australia
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