The palaeomerycid Ampelomeryx ginsburgi is one of the most iconic mammals found at the early Middle Miocene fossil site of els Casots (Catalonia). To date, several investigations have addressed its taxonomy and phylogeny, but many aspects of its paleobiology still remain to be studied. Here, we performed a paleohistological analysis on several limb bones to provide a first insight into its growth and life history. Specifically, we studied bone tissue types and bone growth marks in four tibiae, one humerus, and two metapodial bones. As in many other mammals, we found that the predominant type of primary bone in A. ginsburgi is fibrolamellar bone, suggesting high growth rates for this extinct artiodactyl. The various analyzed bones, however, differ in the orientation of the vascular canals, likely because they experienced different biomechanical stresses and exhibited different rates of intrinsic growth. Different types of secondary tissue, including compacted coarse cancellous bone, were also found. The skeletochronological study focused on the tibia, where we observed that the external fundamental system always appears after the third cyclical growth mark. This suggests that A. ginsburgi achieved skeletal maturity after its third year of life. Growth plots, on the other hand, revealed that reproductive maturity occurred after the second year of life. All in all, our study provides a preliminary understanding of the paleobiology of A. ginsburgi from els Casots and sets the stage for further investigations.
Viladot et al. (Sun,) studied this question.