Earliest siphuncle-bearing cephalopod from the early Cambrian

TL;DR - A newly described early Cambrian fossil, Eoceras shaanxiense, may be the oldest known cephalopod with a siphuncle-like structure. It pushes cephalopod origins earlier and illuminates how buoyancy-controlling chambered shells evolved.

• The fossil preserves shell septa and a segmented tube resembling a primordial siphuncle.
• These features suggest that key components of the cephalopod buoyancy system emerged early in the Cambrian.
• The find provides evidence for the stepwise assembly of chambered cephalopod shells.