history of being difficult to classify, there have been several attempts to enforce consistency in the naming of ichnotaxa.

The first edition of the International Code of Zoological Nomenclature, published in 1961, ruled that names of taxa published after 1930 should be 'accompanied by a statement that purports to give characters differentiating the taxon'. This had the effect that names for most ichnofossil taxa published after 1930 were unavailable