A rolling moss that gathers no stones

The Cambrian Period saw the appearance of all major animal groups. Well, nearly all – a notable absence is the Bryozoa, or moss animals. These tiny creatures that form seaweed-like or encrusting colonies are common in the modern world (though most people miss them), but their fossil record only seems to go back as far as the early Ordovician. The presence of established Bryozoa classifiable into modern groups even at that early date suggests a significant history in the Cambrian, but all supposed Cambrian Bryozoa have been very debatable. Here the authors look at new (and exquisite) specimens of a Lower Cambrian creature, some of which have already been described as a colonial organism of uncertain affinity, and show that it is a primitive bryozoan.