The fossil, Shishania aculeata, was originally thought to be an early mollusc, a group that includes snails and clams.

Learn more about a time period marked by an intense burst of evolution. 3 min read The Cambrian period, part of the Paleozoic era, produced the most intense burst of evolution ever known.

Internal, genetic factors were also crucial. Recent research suggests that the period prior to the Cambrian explosion saw the gradual evolution of a "genetic tool kit" of genes that govern ...

the most severe biological crisis since the Cambrian period. The research, published in Science Advances, challenges the widely held view that terrestrial ecosystems suffered the same catastrophic ...