The seas of the Carboniferous period remained the most abundant and diverse environment for life. Particularly many species lived in broad shallow seas, reaching depths of several tens of meters, stretched across the expanses of the continental plates of primordial Earth.

As in previous periods, the vegetation mainly consisted of red (Calcifolium, Archaeolithophyllum) and green algae, forming the basis of the underwater landscape. Nearby rose "living forests" of bizarre echinoderm animals - sea lilies (Cyathocrinites), filtering the smallest planktonic creatures from the water. Coral-algae reefs rose along the shores.

Various invertebrates lived on the seafloor. However, after the great Devonian extinction, their composition and appearance changed slightly. For instance, trilobites, one of the main underwater inhabitants of ancient periods, were almost nowhere to be seen. They did not go extinct, but their numbers were significantly reduced, and the average trilobite became no la...