•Ichnology is the study of trace fossils.
•Ichnotaxonomy is the nomenclature of trace fossils. By tradition, every distinct trace fossil has its own ichnospecies and ichnogenus, independent of the taxonomy of the trackmaker.
•Another parallel ichnotaxonomy is a system based on the behavior represented by the fossil.
•Yet another set of descriptors are ichnofacies: a set associated ichnofossils that characterize particular environmental settings.
"No one can pass through life, any more than he can pass through a bit of country, without leaving tracks behind, and those tracks may often be helpful to those coming after him in finding their way."
--1940 letter by Robert Baden-Powell, founder of scouting
Ichnology: Study of trace fossils (biogenic sedimentary structures). Ichnite: general term for a trace fossil.
An important distinction to remember is that every mark made by an organism (or fossil) is necessarily a trace fossil. It could simply be a tool mark (for instance, by a shell being bounced around in a current).
Ichnofabric & bioturbation: degree of overturning of sediment by organisms. Excessive biological activity obliterates individual trace fossils and sedimentary structures, mixing layers, etc.
Ichnotaxonomy: by tradition, individual trace fossil forms are given "ichnogenus" and "ichnospecies" (and "ichnofamily" and so on) names, even though they do NOT in reality represent a nested hierarchy based on patterns of descent!! Two trace fossils represent the same ichnospecies if they are identical in form regardless of whether they are made by the same species or
different species; additionally, the same species can produce many different ichnospecies depending on its behavior, the substrate, etc.
Fugichia: escape traces
Fodinichnia: Deposit feeding (3-D)
Ichnofacies: set of trace fossils associated with a particular set of environmental conditions. Form excellent record of paleoenvironment, esp. as many ichnogenera persist for hundreds of millions of years! Some major ichnofacies:
Skolithos: Rapidly moving sediment, made by filter