Alzarian

The Alzarians were one of three closely related species on Alzarius. (DW: Full Circle)

Biology
They are nearly identical to Humans, though they could heal much faster. (DW: Full Circle)

Society
The Alzarians lived in a simple culture with three Deciders as leaders. They believed that they were the descendants of the Terradonians who crash-landed on the planet. Because of this, they attempted to repair the spaceship the Terradonians who crashed in, though they didn't have any driving instructions. In reality, they are actually Marshmen who developed into a more Terradonian form. (DW: Full Circle)

History and evolution of Alzarians
A ship from Terradon crashed on Alzarius, a planet of hyper-evolutionary creatures. The Terradonians were replaced by the humanoid Alzarians (i.e. the marsh men), but were unable to make the starliner take off.

The evolving society lived in fear of Mistfall, a period every 50 years or so, when the influence of another planet took Alzarius away from the sun's warmth. This acted as a 'trigger' to the marsh creatures to emerge onto the land. During this period the people; ignorant of their true heritage, shut themselves away in the starliner. The spiders then eventually evolved into marsh men (their poison establishing a symbiotic link with the marsh creatures).

The people then believed they were Terradonians, and that they had been stranded there for 40 generations, but were gradually mending their ship. In actual fact, the ship was completely operational, and successions of advanced Alzarians had lived around the starliner for 4000 generations (approximately 140,000 years).