Definition
Opisthobranchia is a subclass of sea slugs and snails 🐌 characterized by having gills located behind their heart. These marine mollusks are incredibly diverse in color and shape, often displaying vibrant patterns. Many species lack a shell or have a reduced internal shell. They are found in a variety of marine habitats, from shallow coastal waters to deep-sea environments. Opisthobranchs include familiar creatures like nudibranchs and sea hares. Some are carnivores, feeding on sponges or other invertebrates, while others are herbivores, grazing on algae. Think of them as the underwater chameleons of the sea.