Riddell was an acquaintance of the Eleventh Doctor, and apparently first met the Doctor shortly before being left alone with two dancers (not that he couldn't manage, according to Riddell). Riddell later accompanied him when he discovered a Silurian Ark hurtling towards Earth in the 24th century. Riddell was eager to hunt once they discovered the ship contained dinosaurs, but was discouraged by the Doctor. Riddell displayed a chauvinistic attitude, although his stance lessened over the course of their adventure as he began to see how capable and strong-willed Amy and QueenNefertiti of Egypt were. Upon the conclusion of their trip, Nefertiti chose to stay with Riddell in the African wilderness. (TV: Dinosaurs on a Spaceship)
John Riddell was charming and charismatic, but at first he appeared to believe that males were superior to females. Riddell flirted with Nefertiti, and remained unintimidated when she warned him that, if they were in ancient Egypt, she could have him executed. Although he was unafraid of flirting with a queen of Egypt, Riddell did not actually flirt with Amy Pond, presumably because she was already married. As a game hunter, Riddell was a brilliant marksman and had an adventurous spirit. He also actually enjoyed life-threatening situations, even stating that he had never been happier whilst fighting a group of dinosaurs alongside Amy. He expressed delight about the fact that he was fighting with a lady at his side, having grown to respect both Amy and Nefertiti during their adventure. (TV: Dinosaurs on a Spaceship)
Multi-adventures reference the rare instance when a companion is shown or stated to have multiple adventures with the Doctor but only appears in a single story.
If a medium is not mentioned, then this incarnation did not have companions who were original to that medium; it does not mean that this Doctor failed to appear in that medium.