The wolf-dragon is indeed one of the mythical beasts brought back from the brink of being extinct by a group similar to those in Jurassic Park. Quite simply, they had no idea what they were doing. Filling in the gaps in the dragon DNA with wolf genes, they expected a dramatic combination of speed and scale-y, flame-y stuff. Instead, what resulted was a much smaller dragon than their previous tests (but we won't talk about those!) that was, you guessed it, about the size of a wolf. Unfortunately, the beast's DNA lacked the genetic material for wings, but it makes up for the lack of flight with incredible speed (to which the reduced wind resistance due to scales and not fur contributes) and an even more incredible sense of smell, being able to follow a scent a week and a half old.

But yes, it breathes fire.

(Because no one uses dragons in sci-fi and there is no rule explicitly saying that they must be forever marooned in the fantasy genre. And technically they could be also used in historical fiction...)