Abstract
Coxofemoral joint pathology was evaluated in a minimum of 17 Canis dirus individuals, including 23 ace- tabula and 23 proximal femora. The specimens are curated at the Page Museum, Rancho La Brea, CA USA. We selected specimens for the appearance of subtle pathology because our observation plan was lim- ited to establishing whether features of coxofemoral degenerative joint disease (DJD) would be observed on the acetabular fossa, medial articular margin, articular bone surface, lateral articular margin, and peri-articular structure. Similarly, evaluation of femora included articular surface and margin, peri-articular structure, and joint capsule attachment.
Acetabula variously revealed fossa osteophytes and/or enthesiophytes, smooth osteophyte rim at the lateral or medial articular margin (or both), increased squaring of the medial ar- ticular margin, articular surface oste- ophytes, and lateral peri-articular os- teophytes. Proximal femora variously revealed articular margin osteo- phytes, a short diagonal osteophyte adjacent to the caudolateral articular margin, and rough osteophyte/ en- thesiophyte line at the cranial joint capsule attachment. Our observa- tions suggest non specific degenera- tive responses to physically vigorous life habits. One implication is that programs intended for control of hip dysplasia in modern canids (CHD) likely are structured erroneously if radiographic breeding exclusion cri- teria include these non-specific fea- tures.