Paleontologists have identified the earliest-known cephalopod equipped with a siphuncle — a tubular extension of the mantle found in shelled cephalopods — pushing back the fossil record of this key evolutionary feature to the Early Cambrian, roughly 520 million years ago. Life reconstruction of Eoceras shaanxiense. Image credit: Dinghua Yang. Cephalopods are a group that today includes octopuses, squid, cuttlefish and nautiluses, and once...
