- For other uses, see Antos.
In 2251, the USS Heisenberg, commanded by Captain Garth, visited the planet. While beaming down to the surface, a transporter accident massively disfigured the captain, who was taught the Antosian technique of cellular metamorphosis as a healing measure. Unfortunately, the technique caused Garth to go mad and attempt to destroy the planet. (TOS episode: "Whom Gods Destroy")
Some native organisms, including the people of this world, had cellular, energy releasing properties. Xenobiologists noted the Antosian dryworm, to a degree, naturally gave off an electrical charge. (TOS episode: "Who Mourns for Adonais?")
Before its people mastered technology, one of their natural sources of transportation was a riding animal called an elleis. Similar to a Terran horse (TNG movie, novelization & comic adaptation: Generations) or Klingon sark (TNG episode: "Pen Pals"), these beasts thrived in the wild, while some were tamed for usage. (TOS novel: Garth of Izar)
A dissident movement slowly formed after Garth's visit and became prevalent in 2269. Garth returned to Antos IV in 2270 and stopped the rebellion. He was appointed as Federation ambassador to the planet soon afterward. His term of office became a personal, lifelong commitment. 
- The Federation FASA supplement claims Antos has five moons, while The Worlds of the Federation says there are none.
A few locations for Antos IV have been put forth over the years.
- Socratii (FASA RPG module: The Federation)
- Antos (ST reference: The Worlds of the Federation)
- Kappa Delphini (ST reference: Star Charts)
Antos IV is uninhabitable at the upper and lower lattitudes due to the extreme cold. The equatorial region is where life is supported with a reasonably warm, temperate climate. 
Some of the stronger metals used for building have luminescent properties. 
- TOS episode: "Whom Gods Destroy"
- FASA RPG module: The Federation
- ST reference: The Worlds of the Federation
- TOS novel: Garth of Izar
- ST reference: Star Charts