A major transition in animal evolution is the origin of bilateral symmetry, which coincided with the evolution of organized nervous systems. Animals with bilateral symmetry are known to prominently feature a complex brain with many different neural cell types located near the front of the animal's head. To understand the appearance of the brain and its diverse neurons studies of the nervous system in animals that diverged early from their ancestor lineage are needed.
In a study published in Proceedings of the Royal Society B, PhD candidate Ryan Hulett (Srivastava Lab) describes the nervous system of the three-banded panther worm, Hofstenia miamia -- an acoel worm that can regenerate organs and even whole body parts. Hofstenia belongs to a lineage of animals that diverged from other bilateral symmetric animals 550 million years ago.
Hulett's study and characterization of Hofstenia will enable biological studies of nervous system formation and regeneration and can help explain the evolution of animal nervous systems.