I am unsure as to whether these heads have originated from the possible infusion of Bull Terriers or if they are a throwback to lines that have a strong link to the old Smithfield breed of England, a breed which is part of the Stumpy makeup and which posessed a truncated 'sheepdog' style of head.
My assumption is that the receeding skull fault, is the result of Smithfield ancestry. I come to this conclusion due to the fact that this trait is also very evident in many modern Australian Shepherds (AS) that I have seen. The AS is a breed that is reputed to be a direct decendent of the Smithfield and its derivatives/offshoots. Like the Stumpy it too has the same natural bobtail gene, inherited from the same ancestor. However, unlike the AS the Stumpy resembles the Australain Dingo in look and appearance, rather than a heavy, well-coated sheepdog.
BODY, AUGULATION AND LEGS: We now turn our attention to the body of the Stumpy. What distinct features/properties must we be looking for that denote type. The Stumpy has a number of specific characteristics, the most important of which include, length of body, length of leg, definition of the waist area,set on of the tail and general joint angulation in the shoulders, stifle and pelvis. All of these areas differ considerable when compared with the required structure in the ACD. Lets address each area individually.
The standard clearly states that the Stumpy is a SQUARE dog. he is approximately the same distance from his brestbone to behind his buttocks and from his whithers to the ground. The ACD however is slightly longer in body than he is tall. Judges must closely asses Stumpies that are long in cast (long-bodied).
Do they also posess other ACD traits, or are they only a little long in back?
Leg length is another unique feature. The stumpy must appear markedly 'higher on leg' than the ACD. He must still show the strength needed for a working dog but the proportions of depth of body to length of leg should be in the ratio of approximately 48:52 as a percentage of total height at the whithers. This compared with the ACD whos ratio is equal with respect to depth of body and lenth of leg, that is 50:50.
Boby shape: The ribbing, depth of chest and width of loin on a Stumpy should be strong just like the ACD. However, the Stumpy posesses a more obviours 'tuck-up' in the waist/underline area. We see tighter skin and less depth in the area directly behind the ribs in the Stumpy. this feature is reminisent of his Dingo heritage. the dingo is a also a tight skinnned dog with a defined waistline.Stumpies have a shorter croup and higher set tail than the ACD. The angles between the bones making up the hindquarters are more open (greater than 90 degrees) than those of the ACD. The Stumpy will carry its tail up while moving, a trait that is a serious fault in his cousin the ACD.
The angulation of the Stumpy is only 'moderate' as apposed to the well angulated ACD. Hence the movement of the Stumpy is very different. Stumpies exhibit a more upright gait which is somewhat more elastic when compared with the ACD who should get down into its shoulders and drop the head while moving. Both breeds should move true and show economy of movement (maximum ground coverage for minimum effort).