Meeting Abstract

100.13  Sunday, Jan. 6  Reconstructing the Bite of the Giant Miocene Piranha, Megapiranha paranensis GRUBICH, JR*; HUSKEY, S; CROFTS, S; ORTI, G; PORTO, J; American University in Cairo; Western Kentucky University; George Washington University; INPA jgrubich@aucegypt.edu

The evolution of gnathostome jaws, along with bite forces that can capture and masticate active prey is a key functional innovation underlying the diversification of early Devonian vertebrates. As a result of their fundamental importance to promoting the success of vertebrates, the jaws and bite forces of extinct species have been repeatedly investigated through computer modeling, bite simulations, and anatomical comparisons to living relatives. Here we present the first ever in-vivo bite forces recorded from wild piranhas (Serrasalmidae) and model their bite using 2-D lever and linkage mechanics. Integrating this empirical data with allometry, bite simulations, and 3-D finite element analyses (FEA), we are able to reconstruct the biting abilities and infer the feeding ecology of the extinct giant Miocene piranha, Megapiranha paranensis. An anterior bite force of 320 N from the black piranha, Serrasalmus rhombeus, is the strongest bite force recorded for any bony fish to date. Results indicate the extinct M. paranensis’ bite force ranged from 1240 – 4749 N and reveal its novel dentition was capable of withstanding high bite stresses and crushing vertebrate bone. Comparisons of body size-scaled bite forces to other apex predators reveal that both S. rhombeus and M. paranensis have among the most powerful bites estimated in carnivorous fishes. Our results provide the first functional insights into the extraordinary biting abilities of piranha jaws as well as provide strong biomechanical inference that M. paranensis was a formidable osteophagous predator of the Miocene.