The seas of the Silurian period were a rich and vibrant world of living creatures. Red algae (Leveilleites) and green algae (Inocladus and Medusaegraptus) created a picturesque landscape. Diverse echinoderms with long stems and intertwining "arms" formed whimsical underwater forests. The seafloor was inhabited by a variety of arthropods, such as trilobites, that burrowed in the sediment in search of food. Amazing mollusks, with shells of different shapes and sizes, filled ancient water bodies. Some of them, for instance, benthic bivalves, were peaceful filter feeders. Cephalopods with long or bulbous straight shells continued to take on the role of dangerous predators. However, they had increasing competition. Not only large sea scorpions posed a threat to marine inhabitants, but also a new group of aquatic hunters - fish. All classes of ancient fish had appeared by the Silurian. Among them were creatures resembling modern sharks, and strange fish with numerous fins - acanthodians (Aca...