Glossary

A **coprolite** is a fossilized piece of animal excrement, classified as a trace fossil (ichnofossil) rather than a body fossil. Coprolites preserve direct evidence of ancient animals' diets and digestive processes through inclusions such as bone fragments, scales, plant fibers, pollen, spores, phytoliths, and parasite eggs. Their mineralization is driven primarily by calcium phosphate, with carnivore coprolites preserving more readily than those of herbivores because digested bone provides an abundant internal source of phosphate that facilitates rapid hardening. As biological records, coprolites occupy a unique position in paleontology: they capture information about food webs, plant community composition, parasitology, digestive physiology, and ecosystem structure that is unavailable from skeletal remains alone. The term was coined by English geologist William Buckland, who read his defining paper before the Geological Society of London in 1829 (formally published in the Society's *Transactions* in 1835), after recognizing that convoluted masses found by fossil collector Mary Anning in Early Jurassic Lias formations at Lyme Regis, England, were the fossilized excrement of ichthyosaurs. Before Buckland's identification, these objects had been known as 'fossil fir cones' and 'bezoar stones.'

A **trackway** is a series of at least three consecutive footprints (tracks) left on a sediment surface by a single moving animal. Classified as a type of trace fossil (ichnofossil), a trackway directly records the locomotor behavior of an animal at a specific moment in time, in contrast to body fossils, which preserve anatomical morphology. From trackways, ichnologists extract a suite of measurements including stride length, pace length, pace angulation, and trackway gauge, which enable inferences about locomotion speed, gait type (bipedal or quadrupedal), posture, and social behavior such as herding or predator-prey interactions. Because trackways form in situ at the precise location where an animal was active, they provide unparalleled evidence for paleoenvironmental and paleoecological reconstruction that skeletal remains—which may be transported far from the animal's living habitat—cannot offer.