Setissi

The Setissi (as they are known by the Martian Dwarfs), a.k.a. "Underwater Warriors", are a race of sapient, aquatic reptilianoids which built vast underwater cities in the icy oceans of a primeval Mars, over three billion years ago.

They are roughly humanoid creatures with scaly green skin, flat faces, black or dark-red pupil-less eyes, and gill-slits on both sides of the head. Their digits are long and webbed, and they wear shell-made helmets on their heads. They also cultivate vast plantations of tree-like sponges and kelp.

Appearances

 * Doctor Omega (Fr.: Le Docteur Oméga), by Arnould Galopin (1906)

Behind the scenes
Due to a striking number of similarities between the two works, there is a popular theory (supported by Terrance Dicks, among others) that Le Docteur Omega can be retroactively interpreted as a Doctor Who adventure, with the titular character being none other than the First Doctor himself. The text in the 2003 Black Coat Press edition of the book is heavily edited to include additional references that support this. Under this interpretation, the reptilian Martians are more than likely to be regarded as the ancestors and/or aquatic relatives of the Ice Warriors.