Postnatal ontogenetic scaling of pampas deer (Ozotoceros bezoarticus celer: Cervidae) cranial morphology

Abstract

The pampas deer Ozotoceros bezoarticus is a medium-sized, elegant, and lightly built cervid that was once a characteristic inhabitant of open grasslands across a wide geographical distribution in South America. In Argentina, the subspecies Ozotoceros bezoarticus celer is the most southern and abundant populations and relatively well represented in osteological collections permitting a morphometric study of cranial ontogeny. We measured 17 cranial variables on an ontogenetic series in order to evaluate the multivariate allometry of neurocranial and splanchnocranial components through developmental stages. The cranial ontogenetic pattern in O. b. celer exhibits a conservative plan in which both sexes share most of the allometric trends except in three variables related to the rostrum. Isometry was detected in 9 out of 17 variables, whereas four grows with negative allometry, and only nasal length showed positive allometry. As for most mammals, those variables related to the neurocranial components and sensorial capsules exhibit negative allometry. The growth of the rostrum indicates that both sexes have longer face than younger. However, the lack of allometry in most of the variables seems to be supporting the idea of a younger with the general appearance of an adult but smaller size.