In terms of terpene cyclization mechanisms, TSs initiate carbocation formation through two primary pathways. Type I TSs catalyze carbocation generation by removing the pyrophosphate group, whereas Type II TSs promote carbocation formation through protonating the olefin or epoxy group present in the substrate. Once the carbocation is formed, a series of reactions including olefin-to-cation cyclizations, hydride shifts, proton transfers, alkyl shifts, and terminal deprotonation or quenching process, leading to the production of diverse terpene scaffolds . Coral TSs predominantly employ the Type I carbocation formation mechanism. Moreover, the biosynthesis of the three dominants coral diterpene scaffolds, cembrane, eunicellane, and biflorane, suggests a hypothesized chemical evolutionary relationship (Fig. ). Initially, eunicellanes were believed to be synthesized through a 2,11-cyclization (this study used 1,10-cyclization for consistency with GGPP carbon numbering system) process originating from cembrane. The identification of eunicellane synthases like Bnd4, AlbS, EcTPS1, and the recently discovered MicA emphasizes the specialized TS dependency for eunicellane synthesis . Notably, a proposed eunicellane formation mechanism indicates the formation of a cembranyl cation intermediate , suggesting an evolutionary link between cembrane and eunicellane TSs. This mechanism is also implicated in the formation of certain eunicellane and biflorane structures (Fig. ).