Early reef-building sponge — Archaeocyathus sp.

Geologic period: Cambrian

Age: Early Cambrian for Smithsonian Archaeocyathus material; the exact age of this individual display specimen is not assigned beyond its Cambrian context here.

Feeding: Filter-feeding is inferred from sponge-like biology; feeding behavior itself is not directly fossilized.

Body plan: Porous, generally cone- or cup-shaped calcareous skeleton.

Evidence: The fossil skeleton directly records body architecture. Ecology and feeding are reconstructed from anatomy, reef associations and comparison with sponge-grade animals.

Why it matters: Archaeocyaths demonstrate that reef ecosystems built by animals appeared very early in the history of complex life.

Plain Language Identity: An extinct reef-building animal belonging to Archaeocyatha, an early sponge-grade group.

What You Are Looking At: The mineralized cup-like skeletal structure of an archaeocyath rather than soft tissue.

Ecosystem: Shallow Cambrian marine environments where archaeocyaths helped construct some of Earth's earliest animal-built reefs.

Preservation: Mineralized skeletal fossil.

Open Questions: Do not reconstruct soft anatomy, color or behavior as directly observed features.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://www.si.edu/object/archaeocyathus-sp:nmnhpaleobiology_12307168; https://ocean.si.edu/through-time/ancient-seas/archaeocyatha

Enrichment Method: SAGE curated research pass; title and scientific name matched; evidence separated from inference

Scientific name: Archaeocyathus sp.

Evidence / representation: Representative evidence-type visual; not the exact specimen.

Representative evidence-type visual; not the exact specimen.

Oceans Before Dinosaurs: The Rise of Complex Animal Life.