Nomen est omen, cognitive dissonance, and homology of memory centers in crustaceans and insects.

Abstract

In 1882, the Italian embryologist Giuseppe Bellonci introduced a nomenclature for structures in the stomatopod crustacean Squilla mantis that he claimed correspond to insect mushroom bodies, today recognized as cardinal centers that in insects mediate associative memory. The use of Bellonci's terminology has, through a series of misunderstandings and entrenched opinions, led to contesting views regarding whether centers in crustacean and insect brains that occupy corresponding locations and receive comparable multisensory inputs are homologous or homoplasic. The following describes the fate of terms used to denote sensory association neuropils in crustacean species and relates how those terms were deployed in the 1920s and 1930s by the Swedish neuroanatomist Bertil Hanström to claim homology in insects and crustaceans. Yet the same terminology has been repurposed by subsequent researchers to promote the very opposite view: that mushroom bodies are a derived trait of hexapods and that equivalent centers in crustaceans evolved independently.