CHIGS

Planet of Origin: Basic chemical compounds from which the Chigs evolved came from Earthm but their evolution took place on the single moon orbiting the Chig homeworld, where they evolved. This moon is sacred to the Chigs because it is where life originated via panspermia and where Chigs still go to be born.

Chigs are a humanoid species which developed a space faring civilisation. They have small, black eyes in recessed eye sockets, with gills on the sides of their head and large, jutting chins. They appear to be unable to survive in atmospheres that support human life as both air and water are poison to them and they must wear armored life-support systems that provide them with the methane they need to breathe.
The Chigs actually evolved from bacteria that originated on Earth billions of years ago: an asteroid collision threw these bacteria into space, carried by meteorites, where they eventually landed on the Chig sacred moon. Life on Earth had already advanced to the eukaryote stage of development, the rate of evolution proceeded slightly faster for the bacteria on their new world, allowing life there to evolve to the point that it could produce the sentient Chigs at roughly the same time that modern humans evolved.
As of the 21st century. Chigs have faster-than-light spacefaring technology and advanced weapon systems. They use a combination of plasma-based energy weapons and ballistic missiles for their aerospace fighters and capital ships. Chig ground forces use anti-gravity hover tanks, anti-personnel plasma weapons and flamethrowers. The Chigs also possess large battleships and a destroyer class vesselr. They also developed a stealth fighter with a hull impervious to standard aerial cannon fire.
Source: Space, Above and Beyond.