In the stage directions in the script for "The Forsaken", the Dopterian who robs Lwaxana Troi was described as a "small, weasely looking Dopterian who looks like a distant cousin to a Ferengi". (Star Trek: Deep Space Nine Companion - A Series Guide and Script Library)
The Dopterians apparently have an automated attack weapon known as a "Dopterian interceptor" according to DS9: "Business as Usual". The name was not verbally given on screen, however, the attacking device was identified as such in the script. (Star Trek: Deep Space Nine Companion - A Series Guide and Script Library)
Dopterians also shared an unusual resemblance to the Kobheerian species; their appearance was almost identical, but Dopterians had Ferengi-like noses, whereas Kobheerians had two large, elongated flat nostrils in the place of a nose.
According to the Star Trek: Star Charts, on the star chart United Federation of Planets I, the Dopterians were from the Dopteria (Kappa Coronae Borealis) system. This system was located in the Alpha Quadrant.