Earth Reptile

Earth Reptile was a title used by Silurians to refer to themselves, ignoring other terms such as "Silurian", "Eocene", and "Homo Reptilia". They referred to their Sea Devil cousins, considered a sub-species, as "Sea Devil Warriors," possibly excluding them from the title. (PROSE: The Scales of Injustice)

During the time of the Earth Empire, it was a broad term for the Silurians, Sea Devils and related species, now accepted by humanity because of their Earth-born ancestry. It was considered to be more politically correct to refer to them as such, (PROSE: Love and War) though some thought the term was offensive and the sign of an assimilationist. (PROSE: Burning Heart) The term, however, continued into the time of the Union. (PROSE: The Crystal Bucephalus)

Speculating on the meaning of "Rep", the Eighth Doctor joked the enemy could be "eighty-seventh-century Earth Reptiles with transforming T.rex time machines" and that the entirety of human history could be a Time Lord attempt at eradicating their causal nexus. (PROSE: The Taking of Planet 5)