Reading the carnivoran skeletal story: An acetabular viewpoint, with suggested implications across geological time

We compared acetabular traits among canid and non-canid museum specimens, using the same pre-established protocols. We hypothesized conserved, intersecting development-growth and insult-response biology, reflecting morphologically and being highly similar across carnivoran taxa. We evaluated acetabular traits from dry bone museum specimens of Vulpes lagopus, Vulpes vulpes, Nyctereutes procyonoides, Urocyon cinereoargenteus, Canis lupus familiaris and Canis latrans. The same was done from Procyon lotor (Procyonidae), Taxidea taxus (Mustelidae) and Lynx rufus (Felidae). We assessed intra-articular structures as: (a) acetabular fossa; (b) medial articular margin; (c) lateral articular margin; and (d) articular surface. Each scoring category included multiple subcategories. The primary observed traits across taxa included variably shaped mineralized foci, bony rimming of articular margins and rough-surfaced or worn articular bone. These traits occurred in a very similar fashion across taxa. We then evaluated only the most frequently occurring 80% of the data within the scoring category, observing only minor differences among taxa. The consistency of trait expression supports broad conservation and intersection of development and response capacities. The exact phylogenetic nature of the trait relationships requires further evaluation across development and growth; usually undetected early life damage; degrees of parallel responses across multiple diarthrodial joints within taxon; and the extent of morphological similarity across other carnivorans and non-carnivorans.