Instead, the closest evolutionary sister of B. lecontii is Brachycybe nodulosa, endemic to Japan. Based on a phylogeny of Brachycybe by , B. petasata is closely related to Brachycybe producta, a species from California. Similarly, B. producta co-occurs with Brachycybe rosea, the latter which is more closely related to B. lecontii and B. nodulosa. Up to now, and from the diverse assemblage of platydesmidan millipedes analyzed, each genus possesses a disparate set of chemical metabolites; however, the defense compounds of a group of closely related species of Platydesmida has not been studied. Here, we report the discovery and structure elucidation of four heterocyclic terpenoid alkaloids, three of which are new to the literature, that are produced by two evolutionary sister species, B. producta and B. petasata. The chemical investigations into three previously unstudied species of platydesmidan revealed that two produce highly related metabolites, indicative of their close phylogenetic relationship, while B. rosea was confirmed to produce 1, similar to its closest relative. Structures were confirmed by comparison to authentic standards, and new natural product structures were elucidated by a combination of total synthesis and 2D NMR analysis.