HISTORY OF ICHNOLOGY

Ichnology as a science actually began in prehistory, when hunter-gatherer societies used the signs of animals (tracks, feces, and other indirect evidence) for acquiring their prey. Ichnology (or, in this case, neoichnology) is thus probably one of the first applied sciences in human history, born out of necessity for survival.

Other aspects of ichnology, such as paleoichnology, became known later in human history, including the observation of dinosaur tracks in Mesozoic strata by Native Americans and other aboriginal peoples and the first recognition of some coprolites as feces in the 17th century. Dinosaur tracks were first documented in 1802 by Pliny Moody in the eastern U.S. but were not studied in any detail until more than 30 years later by Edward Hitchcock.

By name, ichnology is a relatively young science and has only reached widespread international recognition in the second half of the 20th century. Probably the first use of the term "ichnology" in the title of a scientific publication was in 1858, Ichnology of New England, by Edward Hitchcock, regarding the vertebrate tracks of Mesozoic strata in the Connecticut Valley, U.S. The naming of invertebrate trace fossils began early in the 19th century, when paleontologists mistook some trace fossils for fossil algae ("fucoids"), reflected in the suffix of many an ichnogenus (i.e., Zoophycos, Palaeophycus, Spirophycus). In 1873, a Swedish paleobotanist, Alfred Nathorst, refuted the algal origin for most of these trace fossils and demonstrated their affinity to modern biogenic sedimentary structures, but his arguments were not readily accepted until later.

Neoichnology of invertebrate organisms in modern times may have actually started with Charles Darwin, who observed the effects of bioturbation by earthworms in his yard during the 19th century. Darwin measured the amounts and rates of soil overturn in his yard by using "wormstones," experiments that took Darwin years to gather data.

With regard to marine environments, the pioneering efforts of Rudolf Richter in the 1920's, where he studied modern traces left in the North Sea tidal flats, lead to a much better understanding of the uniformitarian principles required for understanding trace fossils. One of the most comprehensive works ever done on invertebrate and vertebrate trace fossils, Vorzeitliche Lebensspuren, was published by Othenio Abel in 1935, soon after Richter began his work. Meanwhile, in vertebrate ichnology, the discovery of Protoceratops eggs and nests in Mongolia by the Roy Chapman Andrews expeditions was one of the most significant finds of the 1920's.

Other than works done by mainly German authors and a few scientists in other countries, relatively little was published in invertebrate ichnology from the 1930's nearly through the 1950's. Vertebrate ichnology was represented during that time by the work of Roland Bird in dinosaur track studies. The works of Adolph Seilacher in the 1950's marked some new innovations in invertebrate ichnology and the beginning of the ichnofacies concept of ichnology, as well as the beginnings of behavioral (ethological) and preservational classification methods for trace fossils.

The difficult task of classifying invertebrate trace fossils became one of the most important life works of Walter Häntzschel, who published the first concise catalog of described and illustrated invertebrate trace fossils in 1962, in a volume of the Treatise on Invertebrate Paleontology. Quantification of bioturbation, a subject originally approached by Darwin, was revisited by H.-E. Reineck in 1963, who proposed semiquantitative categories for amounts of bioturbation in a vertical sequence of sediment. Work in ichnology increased throughout the 1960's and 1970's and the efforts of British paleontologists Peter Crimes and James Harper, as well as American paleontologist Robert Frey, resulted in several trace fossil books that attempted to popularize the subject more amongst geologists.

Ichnology in the 1980's was represented by a renaissance in vertebrate ichnology, especially with regard to dinosaur tracks and dinosaur eggs. Martin Lockley began much of the documentation of the numerous dinosaur tracksites in the western U.S. and other areas of the world. John Horner, through his description of dinosaur nests and associated body fossils in Montana, U.S., demonstrated for the first time parental care and nurturing behavior in dinosaurs. Guiseppe Leonardi also made a major contribution to vertebrate ichnology through his 1987 publication of the Glossary and Manual of Tetrapod Footprint Palaeoichnology. Invertebrate ichnology had matured enough that the ichnofacies concept became a commonly taught part of sedimentology and paleontology courses at universities worldwide. The applicability of ichnology to the interpretation of depositional environments lead to its use in petroleum exploration, which has been exemplified by the continuing work of George Pemberton. Quantification of bioturbation was revisted again by the work of Mary Droser and David Bottjer in the mid- to late-1980's and other marine invertebrate ichnologists, such as Richard Bromley and Tony Ekdale, began to incorporate this work into their concepts of ichnofabric analysis through the 1990's. Gatherings and discussion of ichnofabric and other aspects of trace fossils have been facilitated by the Ichnofabric Workshops, which started in 1991 and have now become a biannual international event.

Probably the most neglected aspect of invertebrate ichnology, continental invertebrate ichnology, has received much more attention in recent years through the work of Luis Buatois, Stephen Hasiotis, Molly Miller, and Gabriela Mángano. This aspect of ichnology will continue to be one of the more exciting fields for discovering more about the evolution of terrestrial ecosystems. Vertebrate ichnology was most recently boosted by Jerry MacDonald, who discovered extensive trackways in Permian strata of New Mexico, U.S. Vertebrate ichnology will undoubtedly still be represented by more dinosaur-related studies, but hopefully the literature will include more representation of fossil tracks and other traces from nondinosaurians, such as those made by birds, mammals, amphibians, reptiles, and fish.

BIBLIOGRAPHY

BIRD, R. T. 1985. Bones for Barnum Brown: Adventures of a Dinosaur Hunter. (Edited posthumously by V. T. Schreiber.) Fort Worth, Texas, Texas Christian University Press, 225 p.

BROMLEY, R. G., 1990, Trace fossils, biology and taphonomy: Special Topics in Palaeontology 3: London, Unwin Hyman, 280 p.

BUATOIS, L. A., and MÁNGANO, M. G. 1993. Ecospace utilization, paleoenvironmental trends, and the evolution of early nonmarine biotas. Geology, 21:595-598.

CRIMES, T. P., and HARPER, J. C. 1970. Trace Fossils. Liverpool, Seel House Press, 547 p.

CRIMES, T. P., and HARPER, J. C. 1977. Trace Fossils 2. Liverpool, Seel House Press, 351 p.

DROSER, M. L., and BOTTJER, D. J. 1986. A semiquantitative field classification of ichnofabric. Journal of Sedimentary Petrology, 56:558-559.

EKDALE, A. A., BROMLEY, R. G., and PEMBERTON, S. G. 1984. Ichnology: Trace Fossils in Sedimentology and Stratigraphy. Society of Economic Paleontologists and Mineralogists Short Course No. 15, 317 p.

FREY, R. W. 1975. The Study of Trace Fossils. New York, Springer-Verlag, 562 p.

HÄNTZSCHEL, W. 1962. Trace fossils and problematica. In R. C. Moore (ed.), Treatise on Invertebrate Paleontology, Part W, Miscellanea. Geological Society of America and Univ. of Kansas Press, p. W177-W245.

HASIOTIS, S. T., and BOWN, T. M. 1992. Invertebrate trace fossils: the backbone of continental ichnology. In C. G. Maples and R. R. West (eds.), Trace Fossils. Short Courses in Paleontology No. 5, Knoxville, Tennessee, Paleontological Society, p. 64-104.

HITCHCOCK, E. 1858. Ichnology of New England. A Report of the Sandstone of the Connecticut Valley Especially Its Footprints. Boston, W. White, 220 p.

HORNER, J. R, and Gorman, J. 1988. Digging Dinosaurs. New York, Workman Publishing, 210 p.

LEONARDI, G. 1987. Glossary and Manual of Tetrapod Footprint Palaeoichnology. Departmento Nacional da Produção Mineral, Brasilia, 75 p.

LOCKLEY, M. 1991. Tracking Dinosaurs: A New Look at an Ancient World. Cambridge, Cambridge University Press, 238 p.

MACDONALD, J. 1994. Earth's First Steps. Boulder, Colorado, Johnson Books, 290 p.

MILLER, M. F. 1984. Distribution of bioenic structures in Paleozoic nonmarine and marine-margin sequences: an actualistic model. Journal of Paleontology, 58:550-570.

NATHORST, A. G. 1873. Om några förmodade växtfossilier. Öfversigt af Kgl. Vetensk. Akad. Förhandl. 1873, 9:25-52 (1874).

OSGOOD, R. G., Jr. 1975. The history of invertebrate ichnology. In R. W. Frey, (ed.), The Study of Trace fossils. New York, Springer-Verlag, p. 3-12.

REINECK, H.-E. 1963. Sedimentgefüge im Bereich der südlichen Nordsee. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 505:138 p.

RICHTER, R. 1927. Die fossilien Fährten und Bauten der Würmer, ein Überblick über ihre biologischen Grundformen und deren geologische Bedeutung. Paläont. Zeitschr., 9:193-240.

SEILACHER, A. 1953. Studien zur palichnologie. I. über die methoden der palichnologie. Neues Jahrb. Geologie Paläontologie Abhandlungen 96:421-452.

Back to the Emory University Environmental Studies Home Page.