THE ICHNOLOGY OF VERTEBRATE TOOTH MARKS

Fossilized tooth marks on vertebrate bone have a lengthy and diverse record. Some of the oldest tetrapod bones, of Late Devonian age, bear tooth marks, and tooth marks on the bones of fishes and marine reptiles are well known from Mesozoic strata. Well-documented Permian and Triassic tooth marks are the bases of the ichnogenera Mandaodonites and Heterodontichnites, and a few names (e.g., Knetichnus, Linichnus, Machichnus) have been proposed for Cenozoic mammalian tooth marks. Jurassic-Cretaceous tooth marks on dinosaur bone are well known, but no ichnotaxonomy of these tooth marks has been proposed. Archaeological studies of Quaternary bone modification are extensive, aimed mostly at distinguishing human activity from nonhuman predation and scavenging. An extensive actualistic literature exists for which to interpret tooth marks, notably those of crocodylians. Indeed, studies of bone modification go back nearly two centuries to the work of Buckland in 1823. Yet, tooth marks remain relatively unstudied by ichnologists Tooth marks are important archives of various kinds of behavior, including predation, scavenging, intraspecific (agonistic) interactions and bone utilization for other purposes, including mineral extraction and tooth sharpening. The ichnotaxobases for tooth mark ichnology are primarily the shape of individual tooth marks and the configuration (spacing, geometry) of multiple tooth marks. A recent suggestion to name tooth marks based solely on the damage produced by a single tooth and to treat multiple tooth marks as compound traces fails to recognize the significance of heterodonty and the variation in dental configurations. We posit that the ideal ichnotaxobase is the tooth marks of an entire dental arcade, and anything less than that should be regarded as extramorphological variants. What is now needed is a true tooth mark ichnology beginning with diverse documentation of the fossil record, compilation and synthesis of the entire record, rigorous ichnotaxonomy and determination of analytical criteria for establishing inferences about the diverse behaviors archived by tooth mark ichnofossils.