TERRESTRIAL VERTEBRATE TRACES AS BIOFACIES INDICATORS: INSIGHTS FROM NEOICHNOLOGY

Terrestrial biofacies in the fossil record are often identified through body fossils, particularly when terrestrial vertebrate remains comprise part of the fossil assemblage. Fortunately, vertebrate tracks also have been long recognized for their utilitarian advantages over vertebrate body fossils, and data derived from tracks are now routinely applied in assessments of terrestrial biofacies from the Devonian through the Quaternary. Additionally, their in-situ occurrence assures more accurate interpretations of where and how vertebrates interacted with their environments. Nonetheless, vertebrate traces are not just limited to tracks, and a review of vertebrate traces in modern terrestrial environments provides a glimpse of their potential as a motherlode of data that can provide for holistic interpretations of terrestrial biofacies. In this respect, paleoichnologists have much to learn from modern trackers, such as those using methods developed by some Native American tribes for describing and interpreting vertebrate traces. These ancient scientific methods are being increasingly augmented by technological applications, such as global-positioning system units and handheld computers, to map vertebrate populations and document vertebrate behavior through time as a function of ecological factors (e.g., habitat, food availability, interspecific and intraspecific competition, and weather). Terrestrial vertebrate traces in modern terrestrial environments include tracks, trails, burrows, borings, nests, lodges, aestivation chambers, roosts, lays, toothmarks and other gnawings, food caches, gastroliths, regurgitants, urination marks, feces, scentposts, territorial scratches (particularly in woody substrates), dustbaths, wallows, antler rubs, and many other categories. Two North American mammals, Ursus americanus (black bear) and Castor canadensis (beaver) are used as examples of modern vertebrates that leave a large variety of such traces in their respective ecosystems. Vertebrate traces (not just tracks) thus collectively provide a myriad of information about the interactions of those species with their environments. Preservation potential for such traces in the fossil record will be evaluated in the given examples and for other types of terrestrial vertebrate traces.