High expression of canines in some Mediterranean roe deer (Capreolus capreolus) populations against the general evolutionary trend

Upper canines do not usually appear in the roe deer (Capreolus capreolus (Linnaeus, 1758)) and their occasional appearance represents the expression of a tooth, as a rudimentary canine, which has been suppressed in the evolution of the group. These dental anomalies could be potentially useful for tracing ancestral genes in local ecotypes and populations. We studied the skulls of 517 adult roe deer males from seven Iberian Peninsula hunting populations looking for canine occurrence and the variations depending on region and ecomorphological variety. A total of 18 specimens had canines (3.48%), but a relationship was detected between the geographic origin and the canine presence. We found upper canines in three populations that were located in the Tagus River Basin, with 6.08%, 10.91%, and 20% prevalences, respectively. In the population with the highest prevalence, we also found a case of duplicated canines on either side of the upper jaw. Here, the high prevalence of upper canines against the evolutionary trend may be a sign of atavistic populations, possibly adapted to a less fibrous diet, in a geographical area connected through the Tagus River Basin, and probably regarding one of the glacial refuges of the Iberian Peninsula.