Distribution of the Chuuk Islands giant millipede, Acladocricus setigerus (Spirobolida: Rhinocricidae), and identification of its defensive compounds

The spirobolidan millipede Acladocricus setigerus (Silvestri, 1897) grows to at least 155 mm long and is so far known only from Chuuk Islands, Micronesia. It occurs mainly in well-shaded habitats, usually on the forest floor and on tree trunks. It sprays defensive secretions from paired, lateral ozopores on trunk segments; the major compounds, identified here for the first time, are benzoquinones. The secretion stains human skin a reddish brown and causes a slight burning sensation, occasionally followed by slight blistering and exfoliation.