Stavrolithids

Stavrolithids are an extinct group of marine invertebrates belonging to the phylum Cnidaria. They are known from the fossil record, primarily from the Devonian period. Their most distinctive feature is their skeleton, which is composed of radiating, star-shaped spicules. These spicules often interlock to form a rigid, cup-like structure. Stavrolithids are believed to have been sessile organisms, attaching themselves to the seafloor. Their exact ecological role is not fully understood, but they likely occupied a niche similar to modern corals or sea anemones. Fossil specimens are relatively rare and are found in specific geological formations. The classification of stavrolithids within Cnidaria has been debated, with some researchers placing them within the class Anthozoa, which includes corals and sea anemones. However, their unique skeletal structure sets them apart from most other anthozoans. The term "stavrolithid" itself derives from Greek words meaning "cross stone," referring to the cruciform shape of their spicules. Study of stavrolithids contributes to our understanding of the diversity and evolution of early marine life during the Paleozoic Era.