Scientists at Curtin University and Flinders University claim to have found “the heart of our evolution” in the fossil of a fish found in a rock formation in Kimberley region of Western Australia claimed to be 380 million years old. This age puts it in the Devonian period of the evolutionary timetable, and the Editor’s summary in Science is entitled “A Devonian heart”. The scientists who studied stated: “We describe the only known example of a three-dimensionally mineralized heart, thick-walled stomach, and bilobed liver from arthrodire placoderms, stem gnathostomes from the Late Devonian Gogo Formation in Western Australia.”
The fossil is a placoderm – an extinct group of fishes that were like sharks but had bony plates covering their head and thorax. The fish was preserved in three dimensions, rather than being flattened, and was embedded in a lump of limestone. According to the research team “preservation occurred through bacterially mediated authigenic mineralization”.
The research team had the fossil scanned with neutron beams and synchrotron x-rays while it was still embedded in the rock. From the scan results they “constructed three-dimensional images of the soft tissues inside them based on the different densities of minerals deposited by the bacteria and the surrounding rock matrix.” From the scans they were able to visualise the structure of the heart, stomach, intestines and liver. The reconstruction revealed the internal organs were similar to living sharks, with a large bilobed liver that could be used for controlling buoyancy and an efficient two chambered heart located just below the gills.
Kate Trinajstic of Curtin University, Perth, who led the study, commented to the BBC: “This is a crucial moment in our own evolution. It shows the body plan that we have evolved very early on, and we see this for the very first time in these fossils.”
The researchers also suggested the efficient heart was a critical step in evolution that enabled it to evolve from a slow-moving fish to a fast-moving predator. According to John Long of Flinders University in Adelaide, “This was the way they could up the ante and become a voracious predator.”
References: BBC News 15 September 2022; ScienceDaily 15 September 2022; Curtin University Media Release 16 September 2022; Science 15 September 2022, doi: 10.1126/science.abf3289
Editorial Comment: The preservation process here is interesting – mineralisation by bacteria. We know from our own experiments that this is a rapid process. This is another reminder that the standard museum story of fish fossilising only after being slowly buried by sediment on the sea floor is false.
Another popular story, reported in these popular media stories, and has been witnessed by this editor at museums, is to tell young children on school visits to museums that they (the children) are just over evolved fish. There is no evidence that placoderms evolved from other kind of creature, even another fish, or were evolving into any other kind of creature, particularly not human beings. Genesis clearly states that sea creatures we created according to the kinds. All the evidence we have of placoderms is that they reproduced after their kind from when they were created until they went extinct.
Nor is there any evidence that these fish were evolving into fierce predators. Having an efficient heart and being able to swim fast means it can get to its food more quickly, but does not tell you what that food was. There is evidence that sharks were originally vegetarian, as Genesis tells us, so there is no reason to believe placoderms did not eat plant foods. As they are now extinct there is no way of knowing what they ate unless we find some preserved stomach contents.
Finally, the classification of the rocks in the Kimberley of Australia as Devonian does not make them 380 million years old. The Devonian period in the evolutionary timetable has become known as “the Age of Fishes” because rocks containing fish fossils were found in Devon in England in the 19th Century. The name had nothing to do with any evolutionary dates. According to GENUKI “Early geologists Adam Sedgwick and Roderick Murchison proposed the name in 1839 as a descriptor for the marine rocks they discovered in southwestern England.” Since then rocks with similar appearance to the rocks in Devon and containing similar fossils have been found in other places, and therefore given the name Devonian.
Creation Research News 14 October 2022
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