Development and Divergence of Canid Morphology, A Critical Review

Submitted by Tara Clever for the Evolution class.

When considering the comparison, it is astonishing that toy poodles belong to the same family as wolves: Canidae. Even more interesting is the observation of the divergence of domestic dogs from wolves. Robert K. Wayne approaches this topic with his paper “Limb Mophology of Domestic and Wild Canids: The influence of Development on Morphologic Change.” His primary objective was to determine whether allometry as an index of development and function is the same in domestic and wild canids. (Wayne 1986)

Bivariate Analysis

Domestic dog breeds have wider long bones than their wild counterparts of the same femur length. When comparing relative long bone width, there was little difference between domestic dogs and wild canids. Metapodial, scapula, and olecranon length difference were ovbious between dogs and wild canids. Long bone width and development reflect that fact domestic dogs do not need to hunt or escape predation.

Discriminate Analysis

General size of all canidae family members, domestic and wild, was analyzed to determine similarity of morphologic patterns. Despite diversity in limb size and proportion, domestic dogs are highly distinguished from all except wolf-like canids. Morphologic separation of wild canids among each other and of domestic dogs and wild species depends on difference in metatarsal and olecranon morphology. This suggested that morphologic evolution abides by phylogenetic boundaries (Wayne 1986).

Ontogenetic Analysis

Similarity of dog-intraspecific and dog-ontogenetic analysis showed that small dog breeds are paedomorphic whereas large dog breeds are hypermorphic. This assumes that diversity of limb diversity is predetermined and reflected in the development of an individual as breeders artificially select domestic dogs for favorable traits.

Conclusion

Wayne’s study indicated that allometry can be utilized as an index of devlelopment and function in both domestic dogs and wild canids. Morphological and bone differences were apparent amongst all members of the canidae family. However, some differences were not as distinguishable between domestic dogs and closely related wolves. As domestic dogs are bred for entertainment value, these differences will become more apparent.

Literature cited

Wayne, R. K. (1986). "Limb Morphology of Domestic and Wild Canids: The influence of Development on Morphologic Change." Journal of Morphology 187: 301-319.