Urbilaterian

• Gave rise to the [[protostomes]] and [[deuterostomes]]
  • Had to be simple based on this
• Based on Hox genes common to most descendants:
  • The Urbilaterian most likely had 6 segments
  • It most likely had 2 eyes
  • It most likely had a heart
  • Had to be complex based on this
• Due to lack of fossil evidence, we don't know much for certain about it