Phenotypic disparity of the elbow joint in domestic dogs and wild carnivores*

Abstract

In this article, I use geometric morphometrics in 2D from a sample of 366 elbow joints to quantify phenotypic disparity in domestic dog breeds, in wild canids, and across the order Carnivora. The elbow joint is a well-established morphological indicator of forearm motion and, by extension, of functional adaptations toward locomotor or predatory behavior in living carnivores. The study of the elbow joint in domestic dogs allows the exploration of potential convergences between (i) pursuit predators and fast-running dogs, and (ii) ambush predators and fighting breeds. The results indicate that elbow shape disparity among domestic dogs exceeds than in wolves; it is comparable to the disparity of wild Caninae, but is significantly lower than the one observed throughout Canidae and Carnivora. Moreover, fast-running and fighting breeds are not convergent in elbow joint shape with extreme pursuit and ambush wild carnivores, respectively. The role of artificial selection and developmental constraints in shaping limb phenotypic disparity through the extremely fast evolution of the domestic dog is discussed in the light of this new evidence.

Radial torsion in dogs with medial compartment disease

“…This discrepancy could lead to misinterpretation of RT angle data and might not reflect the true torsional profile of each breed. However, the current literature, although limited, does not support significant variation in the RT angle between breeds …”

“…However, the current literature, although limited, does not support significant variation in the RT angle between breeds. 32,35,40,55,56 The fact that all animals in the study group exhibited distinguishable clinical, radiographic, CT, and, in most cases, arthroscopic data clearly identifying them as diseased exposes this study to selection bias. Because the landmarks for the proximal reference line lie in the same plane as the coronoid process, blinding the observers to the disease status of each individual was not possible, potentially exposing the study to test reviewer bias.…”

Spatial Subchondral Bone Density Reflecting Joint Loading of the Talus in Different Canidae

“…In the elbow joint, morphometric differences exist between breeds, and between different Canidae species based on their way of sourcing food. 30 Although there are currently no data available on differences in joint kinematics and kinetics in the specific breeds used in this study, the differences in subchondral bone density distribution indicate potential differences in joint loading patterns. The relationship between differences in loading pattern, locomotion and orthopaedic pathology remains subject to further research.…”

“…Morphometric studies in the elbow joint of carnivores have shown differences in joint anatomy linked to hunting methods. 30,31 Additionally, the grey wolf and the golden jackal were evaluated. The latter was included as the species that is a close relative to the domesticated dog, despite marked size differences.…”

Digest: Pursue or ambush? Phenotypic disparity in the carnivore forelimb*

“…The elbow joint can be used as a proxy to distinguish whether a carnivore hunts using a stalk-and-ambush strategy or by pursuing its prey. Here, Figueirido (2018) assesses whether elbow joint phenotypic disparity in domestic dogs exceeds that seen in wild carnivores, as has previously been found to be true for the * This article corresponds to Figueirido, B. 2018 skull (Wayne 1986).…”