A revision of brain composition in Onychophora (velvet worms) suggests that the tritocerebrum evolved in arthropods.

ABSTRACT:

Background

The composition of the arthropod head is one of the most contentious issues in animal evolution. In particular, controversy surrounds the homology and innervation of segmental cephalic appendages by the brain. Onychophora (velvet worms) play a crucial role in understanding the evolution of the arthropod brain, because they are close relatives of arthropods and have apparently changed little since the Early Cambrian. However, the segmental origins of their brain neuropils and the number of cephalic appendages innervated by the brain--key issues in clarifying brain composition in the last common ancestor of Onychophora and Arthropoda--remain unclear.

Results

Using immunolabelling and neuronal tracing techniques in the developing and adult onychophoran brain, we foun

SUBMITTER: Mayer G 

PROVIDER: S-EPMC2933641 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature