|Cause of Death||Sprayed by hydrochloric gas|
|Killed by||Dean, Dr. Bruce Abbot|
|Family|| Patrick Ross † (Father)|
Unnamed prostitute † (Mother)
Various Siblings †
|Abilities||Transform to alien form, Strong animalistic instinct of procreation, Rapid regeneration, Penis-tentacle for impregnating females or killing, and long sharp tentacles that come out of his hand.|
|Played by||James Leo Ryan|
Yosef is a character from Species III. He was one of the half-breed sons of Patrick Ross with a unknown and unnamed human mother from the previous film, and is one of the survivors from the previous film.
Yosef was riding in a train when Sara feels his presence and tries to reach him, but she falls and gets her arm cut off. Sara's arm regenerates itself, and Yosef later tracks her down.
When Sara realizes that he is in town, she goes to a hotel where she waits for him. Once Yosef arrives and checks into a hotel room, the two begin to mate, but Sara rejects him after she realizes that he suffers from diseases, and even knocks out one of his teeth. Later on, Yosef breaks into Dr. Abbot's house, and attacks Sara and tries to impregnate her. Abbot sprays hydrochloric gas over the lab, Yosef kills Abbot and soon after dies from the hydrolic gas.
- He shares the same eye color with Amelia in his alien form.
- He attempted to impregnate Sara in the same way that Patrick impregnated Eve.