given by the author, which means an explicit statement concerning the process of replacing the previous name. It is not necessary to employ the term nomen novum, but something must be expressed concerning the act of substituting a name. Implicit evidence ("everybody knows why the author used that new name") is not allowed at this occasion. Many zoologists do not know that this expressed statement is necessary, and therefore a variety of names are regarded as having been established as new replacement names (often including names that were mentioned without any description, which is fundamentally contrary to the rules). The author who proposes a new replacement name must state exactly which name shall be replaced. It is not possible to mention three available synonyms at once to be replaced. Usually, the author explains why the new replacement name is needed. Sometimes we read "the species cannot keep this old name P. brasiliensis, because it does not live in Brazil, so I propose a new name P. angolana". Even though this would not justify a new replacement name under the Code's rules, the author believed that a new name was necessary and gave an expressed statement concerning the act of replacing. So the name P. angolana was made available at this occasion, and is an objective synonym of P. brasiliensis. A new replacement name can only be used for a taxon if the name that it replaces cannot be used, as in the example above with the snail and the spider, or in the other example with the Italian and the Bolivian snail. The animal from Angola must keep its name brasiliensis, because this is the older name. New replacement names do not occur very frequently, but they are not extremely rare. About 1% of the currently used zoological names might be new replacement names. There are no exact statistics covering all animal groups. In 2,200 names of species and 350 names of genera in European non-marine molluscs, which might be a representative group of animals, 0.7% of the specific and 3.4% of the generic names were correctly established as new replacement names (and a further 0.7% of the specific and 1.7% of the generic names have incorrectly been regarded as new replacement names by some authors). Algae, fungi and plants For those taxa whose names are regulated by the International Code of Nomenclature for algae, fungi, and plants (ICNafp), a