jan 1, 530000000 BC - The first true vertebrate

Description:

The first true vertebrate – an animal with a backbone – appears. It probably evolves from a jawless fish that has a notochord, a stiff rod of cartilage, instead of a true backbone. The first vertebrate is probably quite like a lamprey, hagfish or lancelet.

Around the same time, the first clear fossils of trilobites appear. These invertebrates, which look like oversized woodlice and grow to 70 centimetres in length, proliferate in the oceans for the next 200 million years.

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