During the Oligocene epoch (33-25 million years ago), a multitude of mammalian species emerged, leaving a complex evolutionary legacy. Among them, anthracotheres and entelodonts stand out in this intricate evolutionary tapestry, representing more evolutionary dead ends than thriving branches. These fascinating creatures, linked to the ancestry of contemporary whales and hippos, showcase a captivating blend of ancestral and evolved features. Anthracotheres were semi-aquatic animals, while entelodonts, colloquially named “hell pigs”, roamed the land. The intriguing morphological traits of anthracotheres and entelodonts have captivated researchers, with anthracotheres displaying anatomical similarities to both pigs and hippos, suggesting adaptation to frugivorous/folivorous diets. On the other hand, entelodonts exhibit cranial and dental characteristics akin to both pigs and carnivores, suggesting at a potential adaptation to opportunistic omnivorous diets, incorporating hunting, scavenging or bone-crushing as in hyenas. This study employed dental microwear i.e., the microscopic features left by food on teeth, to analyze these assumptions and discern the dietary habits of anthracotheres and entelodonts. The results revealed distinctive dietary patterns. Entelodonts exhibited an omnivorous diet similar to wild boars. In contrast, the analyzed anthracotheres displayed traits indicative of opportunistic browsing, frugivory, and grazing herbivory. These findings shed light on the diverse ecological niches occupied by these taxa during the Oligocene, marked by a rich variety of food resources.
Beyond contributing to our understanding of the paleoecology of anthracotheres and entelodonts, this study provides insights into the digestive system characteristics of fossil artiodactyls. The utilization of an extensive dataset in this research facilitates a nuanced dietary reconstruction, offering a glimpse into the feeding behaviors of these less-explored mammalian taxa.
