Terreneuvian

The Terreneuvian or Early Cambrian is the oldest part of the Cambrian. It was a time when many new kinds of life first appeared on Earth.

It began about 538.8 million years ago. This start is marked by the first appearance of a special trace fossil called Treptichnus pedum. This fossil shows the path an ancient worm made as it moved through mud on the ocean floor.

The Terreneuvian ended about 521 million years ago. This is when the first trilobites appeared in the rocks. Trilobites were small sea creatures with hard shells. They became very common after that.

The name Terreneuvian comes from Terre Neuve. This is the French name for the island of Newfoundland in Canada. Many important rocks from this time were found there. These rocks helped scientists learn more about this period. The International Commission on Stratigraphy officially recognized this name in 2007.

GSSP

The Terreneuvian period starts at a place called Fortune Head in Newfoundland, Canada. This spot has layers of rock that help scientists learn about Earth's very old history.

Signs that mark the beginning of this period include tracks made by ancient animals named Treptichnus pedum. After that, the first simple animals with shells appeared. Later, the first trilobites showed up, marking the start of the Branchian Series.

Major events

The second phase of the Cambrian explosion happened during the Terreneuvian. Many new kinds of animal groups appeared. These included lophotrochozoan animals and some early metazoan animals with hard shells. Another group called deuterostomes was not present, except maybe one possible animal called Yanjiahella from an earlier time.