conulariids

Conulariids were a diverse extinct group of marine invertebrates that lived from the Cambrian to the Triassic periods. Their fossil remains are characterized by a distinctive, cone-shaped or pyramidal exoskeleton called a theca. This theca was typically composed of a chitinophosphatic material and often exhibited intricate surface patterns of zigzag lines or ribs. The overall shape ranged from slender and elongated to broad and squat.

The exact taxonomic placement of conulariids has been a subject of debate for many years. They were once thought to be related to jellyfish or corals, but current research often places them within the phylum Cnidaria, although their precise affinities are still not fully resolved. Some studies suggest a relationship to scyphozoans (true jellyfish), while others propose a more basal position within Cnidaria.

Conulariids are found globally in marine sedimentary rocks. They likely lived in a variety of environments, from shallow to deep water. Their feeding mechanisms are not well understood, but their presence in fossil assemblages suggests they were an integral part of ancient marine ecosystems. The preservation of conulariid fossils is often excellent, revealing fine details of their external morphology and providing valuable insights into paleoecology and evolutionary relationships. Their extinction at the end of the Triassic marks the end of a long and successful evolutionary lineage.