Jarlath's species was a species native to the Delta Quadrant. They preferred desert-like environments. Culturally, they had a concept of a barter system and considered species that didn't to be unsophisticated.
At least nine years prior to 2373, a group including Jarlath was abducted from their colony by the Nyrians, who incarcerated him in their biosphere vessel. He later made contact with the crew of the USS Voyager, and cooperated in their mutual escape. (VOY: "Displaced")