Dune Runner

Dune Riders are or were small and savage creatures indigenous to the desert world of Zz'gash. They were one of a number of species who were absorbed and assimilated into the Zerg Swarm, with this specific species forming the basis for the Zerglings.

Coincidentally, the fact that the Zerglings' core species is known may suggest that some Dune Runners have successfully escaped assimilation; at the same time, however, it could also just mean that they were known of before their obliteration and transmogrification. Because of this second and likely possibility, they must be considered extinct/extinct in the wild until further notice.