Extended Data Fig. 10: Tracing the genetic drivers of neuron diversity and behavior innovation in the spider.
From: Single-cell transcriptomics reveals the brain evolution of web-building spiders

The three key evolutionary steps for web-building emergence are shown: ~500 Ma, the common ancestor of chelicerates; ~350 Ma, at the common ancestors of spiders; and ~200 Ma, at the common ancestors of Araneomorph spiders. Ma, million years ago.