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31st January 2017
01:09pm GMT

Professor of Evolutionary Palaeobiology at the University of Cambridge, Simon Conway Morris, thinks the finding may represent the primitive beginnings of a very diverse range of species,
"To the naked eye, the fossils we studied look like tiny black grains, but under the microscope the level of detail is jaw-dropping. All deuterostomes had a common ancestor, and we think that is what we are looking at here."The research team say that most other early deuterostome groups are from about 510 to 520 million years ago, when they had already begun to diversify into not just the vertebrates, but animals such as starfish and sea urchins and groups including things like worms. This level of diversity has made it extremely difficult to work out what an earlier, common ancestor might have looked like. Until now.
"Our team has notched up some important discoveries in the past, including the earliest fish and a remarkable variety of other early deuterostomes. Saccorhytus now gives us remarkable insights into the very first stages of the evolution of a group that led to the fish, and ultimately, to us."The Saccorhytus microfossils were found in Shaanxi Province, in central China, and pre-date all other known deuterostomes. By isolating the fossils from the surrounding rock, and then studying them both under an electron microscope and using a CT scan, the team were able to build up a picture of how the creature might have looked and lived. The study suggests that its body was bilaterally symmetrical (a characteristic inherited by many of its descendants, including humans) and was covered with a thin, relatively flexible skin. This in turn suggests that it had some sort of musculature, leading the researchers to conclude that it could have made contractile movements, and got around by wriggling. Perhaps its most striking feature, however, was its rather primitive means of eating food and then dispensing with the resulting waste. Saccorhytus had a large mouth, relative to the rest of its body, and probably ate by engulfing food particles, or even other creatures. A crucial observation are small conical structures on its body. These may have allowed the water that it swallowed to escape and so were perhaps the evolutionary precursor of the gills we now see in fish. But where did their poo go?
"Any waste material would simply have been taken out back through the mouth, which from our perspective sounds rather unappealing."Mingin'. Won't be inviting him to the family reunion with table manners like that. Main image: Broad City/ Comedy Central
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