Original paper

On the doctrine of ichnotaxonomic conservatism: the differences between ichnotaxa and biotaxa

Miller III, William

Abstract

If the aim of ichnotaxonomy is to develop a practical and biologically realistic system of delimiting and naming trace fossils, it is important to keep five precepts, or guiding principles, clearly in view: (1) ichnotaxonomy (in general representing behavioral records) and biologic taxonomy (representing evolutionary products such as species and clades) are never equivalent; (2) ichnogenera stand for major structural themes of preserved behavioral patterns or patterns of substrate modification (defined using exclusive, essential characters or primary ichnotaxobases); (3) ichnospecies stand for (intergrading or discontinuous) variations on these major themes (defined using characters or ichnotaxobases of secondary rank); (4) just enough ichnotaxa should be delimited and named to fill out the possibilities of character space (resulting in a nomenclatural system that is both realistic and neither over-divided nor impoverished - the 'middle path' of naming trace fossils); and (5) descriptions and interpretations of ichnotaxa must be kept absolutely separate (to the point of isolating them in different sections of publications). Most ichnologists already follow these guidelines; losing sight of them, however, has resulted in blurring of ichnotaxa and evolutionary units, excessive lumping or splitting that obscures actual diversity, and a reputation for a largely arbitrary system of delimitation and naming of trace fossils.

Keywords

trace fossilsichnotaxa vs. biotaxadelimitationcharacter spacevariationichnotaxonomic conservatism