Complex sentence: Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from close ancestors of cockroaches during the Jurassic or Triassic, but it is possible the first termites emerged during the Permian or even the Carboniferous.
Split into simpler sentences: Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from close ancestors of cockroaches during the Jurassic or Triassic. However, it is possible the first termites emerged during the Permian or even the Carboniferous.