This is the fossil of an ancient, shrimp-like thing that lived in the oceans more than half a billion years ago. Jie Yang / Jie Yang / SWNS.com It’s called Chengjiangocaris kunmingensis, and it was found in southern China. It lived about 300 million years before the first dinosaurs arose, and now it has been examined by scientists from the UK, Germany, and China in a study published in the journal Proceedings of the National Academy of Sciences. It's from a period in Earth's history called the "Cambrian explosion". Beforehand, the world was dominated by simple, single-celled organisms; suddenly, there was a profusion of complex life. Trilobites, one of the life forms that arose in the Cambrian explosion. By Heinrich Harder (1858-1935) - The Wonderful Paleo Art of Heinrich Harder, Public Domain / Via commons.wikimedia.org That's "suddenly" in evolutionary timescales, of course. The "explosion" took more than million years, from about 542 million years ago to about 520 million years ago, when C. kunmingensis lived. It's pretty amazing to find anything that old. But the C. kunmingensis is especially exciting, because unusually, its nervous system has been preserved. Jie Yang / Jie Yang / SWNS.com Most of the time, fossilisation only preserves the hard parts of a dead animal – the bones of a dinosaur or a mammal, the shell of a crustacean, the teeth of a shark.But very rarely, the mud the creature dies in preserves the soft tissue as well. In this C. kunmingensis fossil, it preserved the whole nervous system, in more detail than has ever been seen in a fossil this old.The pink-purple line up the middle is its ventral nerve cord – a bit like a spine in a human – and at the top of the picture is its brain. The discovery will teach scientists huge amounts about how nerves and brains developed when complex life first arose. Yu Liu / Yu Liu / SWNS.com This is a closeup of the nerves in its ventral nerve cord. C. kunmingensis is the ancestor of modern arthropods, such as crabs, shrimps, and insects. A small, vaguely eel-like creature called Metaspriggina walcotti was swimming around at about the same time as C. kunmingensis. By User:Giant Blue Anteater (moved from English Wikipedia) [Public domain], via Wikimedia Commons / Via commons.wikimedia.org It was probably the ancestor of all vertebrates – everything from fish to crocodiles to hedgehogs to humans.