At various times during its history, the breed (and direct ancestors of the breed) were known as Rat - Tail Spaniels, Whip - Tail Spaniels, and Shannon Spaniels. (dogbreedstandards.com)
Other ancestors of the breed include Welsh Terriers, English Wirehaired Terriers, and German Pinschers. (animalso.com)
A likely ancestor of the breed was the Techichi, a sacred dog of the ancient Toltecs. (thesprucepets.com)