Cambrorhytium

Cambrorhytium is an enigmatic genus of conical fossil known from the Chengjiang biota of China, the Burgess Shale of the Canadian Rockies, and the Latham Shale of California, spanning the Middle Cambrian. It has thin walls marked with parallel linear ridges and lacks the keel found in hyoliths, and roughly 350 specimens are known from the Burgess Shale Greater Phyllopod bed alone, about 0.7 percent of that fossil community. It is generally interpreted as a cnidarian, most likely a polyp that lived inside its tube shaped structure and extended tentacles from its flat opening, and is classified within the order Conulatae.