The Reptilians, like the other Xindi species, evolved on the planet Xindus in the Delphic Expanse. In the the 2030s, during their civil war, the Reptilians then made an alliance with the Insectoids. In one of their last desperate actions during their Civil War, the Reptilians and Insectoids planted explosives under Xindus's eight largest seismic fissures. This had the unintentional result of destroying Xindus due to its high geological instability. They like the other species, except the Avians, went into space as part of the "Great Diaspora".(ENT episodes: "The Xindi", "The Shipment"; ST reference: Federation: The First 150 Years)