Ancient Fossil Unveils Cambrian Explosion Secrets

A fossil tunicate named Megasiphon thylakos, discovered in the mid-Cambrian Marjum Formation of Utah, provides evidence of an early biphasic life cycle and suggests that fundamental components of the modern tunicate body plan were established shortly after the Cambrian Explosion. The fossil could potentially push back the origins of vertebrates, including humans. The discovery adds to the growing body of evidence supporting the abruptness of the Cambrian Explosion and challenges Darwinian evolution.