The phylogeny of animals described in the text. The presence and absence of mushroom body-like structures are indicated with Y and N in red, respectively. The presence and absence of PsGEF with C2, PDZ, and RhoGEF domains are shown with Y and N in blue, respectively. The status is not known in annelids and platyhelminthes, and thus indicated with ?. Representative animal species are also shown in parentheses. Not all animal phyla are indicated.