Additional file 2: of Insights into the segmental identity of post-oral commissures and pharyngeal nerves in Onychophora based on retrograde fills

Scenario on the evolution of the onychophoran brain. Animation, swf file. Anterior is up. The composite brain of onychophorans (sensu Richter et al. [5]) most likely evolved by anteriorly moving somata, which give rise to the deutocerebrum.