THE FOSSIL RECORD OF DENTALITES (BITE MARKS) AND THEIR IMPORTANCE

Dentalites encompass all trace fossils produced on a substrate by the teeth or oral cavity of a vertebrate. The substrate is most commonly bone but can be vegetation, invertebrate hard parts or even a coprolite. The study of vertebrate dentalites dates back to 1822.

Some of the oldest tetrapod bones, of Late Devonian age, bear putative dentalites. Permian dentalites are well documented, and there are several described Triassic dentalites; two of these are the basis of the ichnotaxa Mandaodonites and Heterodontichnites. There is a diverse literature on dentalites in Jurassic-Cretaceous dinosaur bones. This is an example of the “taxophile effect”—bias introduced by a disproportionate volume of research on a popular taxonomic group. Dentalites on Mesozoic aquatic vertebrate bone (fishes, marine reptiles) also have a diverse literature. Sharks were notable scavengers of vertebrate carcasses during the Cretaceous. There are several reports of dentalites attributed to marine reptiles and fish, principally mosasaurs, on cephalopod shells (ammonites and nautiloids), mainly from North America. Some may have been produced by limpets, but most are true dentalites.

Reports of dentalites are relatively common from the Tertiary but even more abundant from the Quaternary. Tertiary dentalites include records from the Paleocene of the USA, Eocene of England and Antarctica, and the Oligocene of France and the USA. Named Tertiary dentalite ichnogenera include Nihilichnus, Bruatlichnus, Machichnus, and Knethichnus. Because of the taxophile effect, the majority of the dentalite literature is focused on: (1) hominin evolution; and (2) dinosaur paleobiology.

Dentalites have the potential to document a wide range of behaviors including: (1) predation, including hunting strategies; (2) bite method and force; (3) dietary selection; (4) feeding; (5) scavenging; (6) bone accumulation; (7) trophic patterns; (8) intraspecific (agonistic) interactions; (9) tooth sharpening; and (10) bone and rock utilization for other purposes, including mineral extraction. The potential of the study of dentalites is largely unrealized. We urge the development of a much more extensive, well documented ichnofossil record of dentalites with which to interpret the evolution of the diverse vertebrate feeding behaviors that they document.