The AKC recognizes the Parson Russell and Russell terriers as separate breeds. The Parson Russell used to be called the Jack Russel but I don't know why since it was developed by a guy named John. The Russell terrier is a spinoff of the Parson and its smaller. Really all the Russell terriers could be split up into so many groups if the kennel club wanted because there's so much variety allowed in the breed as far as coat type, height, and even button or prick ears. The Jack Russell in Europe is a short-legged version while a Parson is longer legged.