Günter Bechly explains why the Precambrian fossil Namacalathus fails as a transitional precursor to the Cambrian explosion.
The notion that many genes would be required for the Cambrian explosion may seem unsurprising — what is surprising is that anyone would challenge the idea.
One researchers has preferred to classify Kimberella among the Ediacaran “fossil problematica.”
One of the few features that are uncontroversial is the body size: The fossils measure usually 1-5 cm in length.
Scientists debate whether ctenophores are the earliest animals to appear in the Cambrian explosion. If so, they arrived with multiple tissues, a nervous system, and a digestive system.