page_title: Trace fossil
section_title: Confusion with other types of fossils
hierarchical_section_title: Trace fossil / Confusion with other types of fossils
caption_attribution_description: English: Asteriacites (a sea star trace fossil) from the Devonian of northeastern Ohio.
context_page_description: A trace fossil, also ichnofossil, is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. Ichnology is the study of such trace fossils and is the work of ichnologists.
  Trace fossils may consist of impressions made on or in the substrate by an organism. For example, burrows, borings, urolites, footprints and feeding marks and root cavities may all be trace fossils.
  The term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites or chemical markers. However, most sedimentary structures are not produced through the behaviour of an organism and thus are not considered trace fossils.
  The study of traces - ichnology - divides into paleoichnology, or the study of trace fossils, and neoichnology, the study of modern traces. Ichnological science offers many challenges, as most traces reflect the behaviour—not the biological affinity—of their makers.
context_section_description: Trace fossils are not body casts. The Ediacara biota, for instance, primarily comprises the casts of organisms in sediment. Similarly, a footprint is not a simple replica of the sole of the foot, and the resting trace of a seastar has different details than an impression of a seastar.
  Early paleobotanists misidentified a wide variety of structures they found on the bedding planes of sedimentary rocks as fucoids (Fucales, a kind of brown algae or seaweed). However, even during the earliest decades of the study of ichnology, some fossils were recognized as animal footprints and burrows. Studies in the 1880s by A. G. Nathorst and Joseph F. James comparing 'fucoids' to modern traces made it increasingly clear that most of the specimens identified as fossil fucoids were animal trails and burrows. True fossil fucoids are quite rare.
  Pseudofossils, which are not true fossils, should also not be confused with ichnofossils, which are true indications of prehistoric life.
caption: Asteriacites (sea star trace fossil) from the Devonian of northeastern Ohio. It appears at first to be an external mold of the body, but the sediment piled between the rays shows that it is a burrow.
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