Natarl

Among the aliens stuck on Denossus was a being with a distinctive helmet and webbed hands and feet. (COMIC: Land of the Blind)

Four of these beings were once at a beach in a valley. (The Dr Who Annual Contents page)

Several of these beings were also seen on the Moon. (Doctor Who Annual 1969 inside cover art)

Behind the scenes
These aliens are Natarls from the film (1959).