1. Geology Department, Macalester College, 1600 Grand Avenue, St Paul, Minnesota 55105, USA
2. Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York 11794, USA
3. Department of Paleontology, Science Museum of Minnesota, 120 West Kellogg Boulevard, St Paul, Minnesota 55102, USA

Correspondence to: Raymond R. Rogers¹ Correspondence and requests for materials should be addressed to R.R.R. (e-mail: Email: rogers@macalester.edu).

Abstract

Many lines of evidence have been brought to bear on the question of theropod feeding ecology, including functional and physiological considerations, morphological constraints, taphonomic associations, and telling—although rare—indications of direct ingestion^{1, 2, 3, 4, 5, 6, 7}. Tooth marks of theropods, although rarely described and generally left unassigned to a particular taxon, can provide unique clues into predator–prey interaction⁸, and can also yield insights into the extent of carcass utilization^{9, 10}. Here we describe a sample of tooth-marked dinosaur bone recovered from three well-documented localities in the Upper Cretaceous Maevarano Formation of Madagascar that provides insights into the feeding ecology of the abelisaurid theropod Majungatholus atopus¹¹. Intensely tooth-marked elements from multiple individuals show that Majungatholus defleshed dinosaur carcasses. Furthermore, Majungatholus clearly fed upon the remains of not only sauropods, but also conspecifics, and thus was a cannibal. Cannibalism is a common ecological strategy among extant carnivores, but until now the evidence in relation to carnivorous dinosaurs has been sparse and anecdotal.