It’s time to eat: great white shark (Carcharodon carcharias) bite marks on balaenid (right whale) remains from the Pliocene of Tuscany (central Italy)

• Main Authors: Merella Marco, Collareta Alberto, Casati Simone, Di Cencio Andrea, Pieri Alice, Bianucci Giovanni
• Other Authors: Cherin, M., Collareta, A., Merella, Marco, Collareta, Alberto, Casati, Simone, Di Cencio, Andrea, Pieri, Alice, Bianucci, Giovanni
• Format: Conference Object
• Language: English
• Published: ESE Publications 2023
• Subjects: baleen whale
• Online Access: https://hdl.handle.net/11568/1208667; https://doi.org/10.1285/i9788883051968; http://siba-ese.unisalento.it/index.php/paleodays/issue/view/1954

Modern marine waters are inhabited by more than 500 shark species. Among them, the great white shark (Carcharodon carcharias) represents the apex predator of the present-day global ocean. Even if C. carcharias is wellknown as a formidable active predator of marine mammals (pinnipeds and odontocetes), it may also behave as a scavenger. In fact, several anecdotal and scientific documentation exists for white sharks feeding on floating whale carcasses, which are rich in blubber, and consequently, highly energetic. Given the latest Miocene origin of C. carcharias, the Plio-Pleistocene marine deposits can preserve evidence of the feeding interaction between white sharks and marine mammals in the form of bite marks on bones and/or teeth embedded into (or closely associated with) marine mammal skeletons. Here, we report on two new examples of white shark-cetacean trophic interaction from the Pliocene of Tuscany (Italy), consisting of two scapulae that are densely incised by serrated shark bite marks, up to several centimeters long. The morphology and regular denticulation of the latter allows for identifying the great white shark as the tracemaker. One scapula, stored in the Museo Geopaleontologico GAMPS of Scandicci (Italy), comes from Monterotondo Marittimo (southern Tuscany), whereas the other is part of the historic collection of Tuscan Pliocene cetaceans of the Museo G. Capellini of Bologna (Italy), but its precise provenance is actually unknown. Based on osteoanatomical considerations, these scapulae can be referred to two distinct species of small balaenids (i.e., right whales). Considering the fragmentary nature of the studied specimens, whether the observed bite marks represent scavenging or active predation could not be assessed. What is remarkable here is the kind of trophic interaction that it witnesses to, which includes members of baleen whale morphotypes that are no longer present in the modern Mediterranean Sea, not even in the rest of the global ocean.