 The status of a synonym may be indicated by symbols, as for instance in a system proposed for use in paleontology by Rudolf Richter.In that system a codice_1 before the year would indicate that the authors have inspected the original material; a codice_2 that they take on the responsibility for the act of synonymizing the taxa.The traditional concept of synonymy is often expanded in taxonomic literature to include "pro parte" (or "for part") synonyms.