Dental occlusal surface and seed dispersal evolution in Tapirus (Mammalia: Perissodactyla)

Abstract

Abstract Most tapirs are good seed dispersers. An exception is the Malayan tapir, Tapirus indicus, a seed predator (mainly of large seeds). Little is known about the capacity for tapirs to disperse seeds throughout their evolutionary history. We used the occlusal surface area (OSA) of tapir cheek teeth as a predictor of seed dispersal potential in living and extinct tapir species. We used T. indicus as a reference for an extant tapir that mostly eats seeds. The OSA was calculated by multiplying the maximal width and length of molars and premolars. A threshold based on T. indicus OSA was projected onto a box plot analysis and used as a predictor for tapir seed dispersal potential. Ordination and statistical results suggest that tooth morphology is uniform between Tapirus species and that size is the main factor affecting variation. Maxillary teeth show greater variation in morphology than mandibular teeth between species. The results suggest that extant South American tapirs are good seed dispersers. North American tapirs present variable OSAs, and Asian tapirs have a low capacity for dispersion. All European tapirs were probably efficient seed dispersers. We present the first morphometric evidence for seed dispersal capacity in tapirs, with ramifications for tapir palaeoecology.