HOW BACTERIA ARE NAMED AND IDENTIFIED 23 



organism cannot be identified from this text is no proof that it has not been 

 described and named. 



(3) It is possible, of course, that an error has been made in the selection of 

 the correct name in this Manual. Bacteriological literature has, in recent years, 

 been engaged in the herculean task of rectifying the nomenclatural blunders of 

 the past. It is desirable, therefore, that users of the keys and descriptions of this 

 Manual should be familiar with the rules governing the correct choice of names, 

 and themselves propose suitable corrections where needed. 



Some general rules governing nonienelature that should be known to 

 students of bacteriology. In summary, some of the more important rules and 

 recommendations of the Bacteriological Code may be briefly paraphrased. In 

 case of doubt, the Annotated Code itself should be consulted. 



1. Every individual microorganism belongs to a species, every species to a 

 genus, every genus to a family, every family to an order, every order to a class. 

 Each one of these ranks is called a taxon (plural taxa) (Principle 7). 



2. Each taxonomic group (taxon) with a given definition (circumscription), 

 position, and rank can bear only one correct name, the earliest name given to it 

 that is in accordance with the rules of nomenclature (Principle 9) . 



3. The name of a species is made up of two words consisting of the name of 

 the genus followed by the specific epithet. The term "epithet" means a single 

 descriptive word or a single descriptive phrase. If the latter, the component 

 words are to be united or joined by a hyphen. Within the same genus, no two 

 species names may bear the same specific epithet (Rule 6). 



4. Each taxon (species, genus, family, order) should have designated a nomen- 

 clatural type. The type of a bacterial species is preferably a designated culture 

 preferably maintained in a national type culture collection. When a new species 

 is described and named, a culture should be deposited by the author with such 

 type culture collection where it will be available as a standard and useful in 

 identification of other cultures believed to be related. 



The nomenclatural type of a genus is a species of the genus selected in accord- 

 ance with the rules. 



The nomenclatural type of a family is a genus contained within the family. 

 The family name is formed by adding the ending -aceae to the stem of the name 

 of the type genus. The nomenclatural type of the family Pseudomonadaceae is 

 the genus Pseudomonas (Rule 9). 



5. Correct names. For the name of a taxon (species, genus, family, etc.) to 

 be correct it must meet certain requirements. The most important of these are 

 as follows : 



a. The name must be the oldest that conforms to the rules. 



b. The name must have been validly published. This means that the name 

 must have been distributed in printed matter (periodicals, books, other 

 publications) together with a description or clear reference to a previously 

 published description. The name must be accepted by the author. It is not 

 validly published if merely cited as a synonym. A name that has not been 

 validly published is without standing in nomenclature. 



