Teela

Teela was a companion to one of the Doctor's first five incarnations.

Teela, Tegan, Leela, Zoe, Romana, Nyssa, and Victoria were a fraction of past companions the Fifth Doctor mentioned to a business woman who also became his companion. (PROSE: Time on a Vine)

Behind the scenes

 * Teela happens to be a portmanteau of Tegan and Leela, the companions listed after Teela.
 * While all the companions the business woman recalled, bar Romana and Nyssa, happen to be female humans, Teela's gender and species are not explicitly mentioned.
 * It is unknown how Teela came to travel with the Doctor, and how they left him.