International Code of Nomenclature of Prokaryotes.

1. Foreword to the First Edition S1–S1 2. Preface to the First Edition S2–S2 3. Preface to the 1975 Edition S3–S4 4. Preface to the 1990 Edition S5–S6 5. Preface to the Current Edition S7–S8 6. Memorial to Professor R. E. Buchanan S9–S12 7. Chapter 1. General Considerations S13–S14 8. Chapter 2. Principles S15–S16 9. Chapter 3. Rules of Nomenclature with Recommendations S17–S40 10. Chapter 4. Advisory Notes S41–S42 11. References S43–S44 12. Appendix 1. Codes of Nomenclature S45–S48 13. Appendix 2. Approved Lists of Bacterial Names S49–S49 14. Appendix 3. Published Sources for Names of Prokaryotic, Algal, Protozoal, Fungal, and Viral Taxa S50–S51 15. Appendix 4. Conserved and Rejected Names of Prokaryotic Taxa S52–S57 16. Appendix 5. Opinions Relating to the Nomenclature of Prokaryotes S58–S77 17. Appendix 6. Published Sources for Recommended Minimal Descriptions S78–S78 18. Appendix 7. Publication of a New Name S79–S80 19. Appendix 8. Preparation of a Request for an Opinion S81–S81 20. Appendix 9. Orthography S82–S89 21. Appendix 10. Infrasubspecific Subdivisions S90–S91 22. Appendix 11. The Provisional Status of Candidatus S92–S93 23. Appendix 12. The van Niel International Prize S94–S95 24. Appendix 13. Activities of the Congresses S96–S111


PREFACE TO THE 1975 EDITION
This volume contains the edition of the International Code of Nomenclature of Bacteria approved by the Plenary Session of the First Congress for Bacteriology, Jerusalem, 1973. The volume also contains the Lists of Conserved and Rejected Names of Bacterial Taxa together with the Opinions issued by the Judicial Commission, and the Statutes of the International Committee on Systematic Bacteriology (ICSB), formerly the International Committee on Nomenclature of Bacteria (ICNB) 1 . These Statutes, which deal with the administration of the ICSB, were developed from Provisions 4 and 5 of the earlier Codes. The Statutes of the Bacteriology Section of the International Association of Microbiological Societies (IAMS) 2 are also included.
A revision of the International Code of Nomenclature of Bacteria [1] has been undertaken in an attempt to simplify the rules of nomenclature, thus encouraging wider use of the Code, and to provide a sound basis for bacterial systematics. This edition supersedes all previous editions of the International Code of Nomenclature of Bacteria.
To achieve these aims, certain principles were recently approved by the ICSB [2], and these have been incorporated into the present edition.
A new starting date (1 January 1980 rather than 1 May 1753) for the nomenclature of bacteria is proposed so as to put into practice more meaningful requirements for the valid publication of names. New names and combinations must be published in the International Journal of Systematic Bacteriology (IJSB) or, if published previously elsewhere, an announcement of such publication must be made in the IJSB; a description or a reference to a previously and effectively published description of the named taxon must also be given in the IJSB and the type of a named taxon must be designated.
The ICSB is requesting its taxonomic subcommittees and other experts to propose lists of characteristics which will constitute the minimal standards for the description of various taxa. When these have been approved by the ICSB, the Code recommends that the description of each named taxon contain at least those characteristics specified in the minimal standards. In addition the Code recommends that, in the case of cultivable organisms, cultures of the type strains of newly named species and subspecies be deposited in culture collections from which they would be available.
For names published prior to 1 January 1980, Approved Lists of Bacterial Names will be compiled by the members of the taxonomic subcommittees and by other experts for approval by the Judicial Commission and the ICSB. Only the names of bacteria which are adequately described and for which there is a type or neotype strain, if the organism is cultivable, will be placed on the approved lists. In determinations of priority after 1 January 1980, then, only those names which appear on the approved lists of names or which are validated by publication in the IJSB after 1 January 1980 need be taken into consideration. Thus it will no longer be necessary to conduct extensive, frequently difficult literature searches merely for the purpose of determining the earliest name that was used for a bacterial taxon. Most important, however, will be the fact that after 1 January 1980 all of the validly published names for the bacteria will have clear and precise applications because the names will be associated with adequate descriptions and with type or neotype strains.
For this edition of the Code, the Drafting Committee prepared several revisions which were circulated to members of the Judicial Commission and to the ICSB for their comments. The work was begun in 1968, approved in principle by the Judicial Commission in 1970 (at the Xth International Congress of Microbiology, Mexico City), and culminated in publication as a proposed Revision in 1973 [3] for comment by the scientific community prior to presentation to the Judicial Commission, the ICSB, and the Plenary Session of the Bacteriology Section of IAMS at its Congress in Jerusalem, 1973. There, the published text was approved (with minor changes) and approval was also given for publication in book form of the text contained in this volume. The date on which this edition of the Code becomes effective is the date of publication of this volume.
Examples have been included in the Code where they were thought helpful to illustrate clauses, but in a few instances examples from bacteriology have not so far been found. These cases have been indicated, as the use of hypothetical examples or those taken from botany would appear to be misleading. In a few cases, however, hypothetical examples have been used to illustrate orthography in Appendix 9. On the authority of the Judicial Commission and the ICSB, some of the earlier Opinions of the Judicial Commission have been edited to remove minor inconsistencies. (1) A new starting document and starting date were achieved with the publication of the Approved Lists of Bacterial Names on 1 January 1980 [1], containing about 2,300 names. Names not on those lists lost their standing in nomenclature, thus clearing away many thousands of useless names. The old names are, nevertheless, available for revival individually if the provisions for doing so are met. This new system of nomenclature came fully into force on 1 January 1980, and the reaction of the bacteriological community was awaited with some trepidation. In the event, it has worked remarkably well and has fully justified the foresight of the two individuals who contributed the bulk of the effort toward it, Professor V. B. D. Skerman and the late Dr. S. P. Lapage. A historical account of these developments has recently been given [2]. The evident success of such a system in bacteriology has led workers in botany and zoology to take a keen interest and to consider whether similar changes should be introduced in their own fields. This is a heartening development, for imitation is the sincerest form of flattery; recent steps here are reviewed by Hawksworth [3], Ride [4], and Hawksworth and Greuter [5].

PREFACE TO THE 1990 EDITION
The new system led to a considerable number of requests to the Judicial Commission in the first few years to adjudicate on cases that required further attention, and progress reports were therefore made on these (for example, [6,7]). New advances, particularly in molecular biology, have led to the need to compare older and newer approaches to taxonomy, and inevitably these advances have implications for nomenclature; reports on these [8,9] are an important new activity of the ICSB. 8

PREFACE TO THE CURRENT EDITION
It is more than 26 years since the 1990 Revision of the Bacteriological Code was published. This revision of the Code now takes on the name The International Code of Nomenclature of Prokaryotes (ICNP), in order to reflect the fact that it governs a larger group of organisms than the Bacteria. The term "prokaryote" is used as defined in General Consideration 5. The wording of the Code reflects those changes approved by Plenary Sessions of the ICSB and ICSP up to and including the Twelfth International Congress of the Bacteriology and Applied Microbiology (BAM) Division of the International Union of Microbiological Societies (IUMS) in Istanbul (2008), together with updated lists of conserved and rejected names, and of Judicial Opinions. The statutes governing BAM, which until 1987 was the Bacteriology Section of the IUMS are no longer included, and will be published separately.
In the 26 years since the last complete edition was published and 38 years since the implementation of a new starting date for prokaryotic nomenclature was introduced, the Code has served the community of prokaryotic systematics well. This revision of the Code would not be complete without honoring the editors of the 1975 and 1990 revisions. Their words can be found in the earlier prefaces, which we include in this volume, and every volume, in order to preserve our institutional history and to record their efforts. The Code would not exist in its present state (or perhaps at all) without their significant contributions. This code is a living document, revised by nearly every Congress as methods and technology advance in our field, and as the needs of the scientific community change. In principle this code of nomenclature retains a stable foundation that, from time to time, requires fine tuning rather than major revision. That the Code has stood the test of time is a tribute to those who undertook the task of maintaining it and are now deceased.
Stephen P. Lapage (1990) Peter H. A. Sneath (2011) Victor B. D. Skerman (1993) Heinz P. R. Seeliger (1997) William A. Clark (2011) Erwin F. Lessel (2012) While the Code regulates nomenclature, one of its main goals is to maintain stability in names, which itself is linked to the classification of organisms and the way the data gathered on organisms is interpreted. The names of taxonomic concepts have taken on a new significance in an increasingly electronic age, where the information in databases, online publications and other resources may be linked. Nomenclature and the associated classifications play a fundamental role in maintaining the identity of the organisms when their names appear out of their usual contexts.
While the Code does not attempt to interfere with the process of classification it does lay down clear rules that stipulate that taxa must be distinguishable, that types must be properly designated and (where appropriate) authentic strains must be made available without restriction, and that data on which descriptions are based must be included. The Code provides the critical links between nomenclature, classification and characterization; past, present and future. It provides the foundation on which we can reliably compare physiological, biochemical, genetic and structural data collected in the past with current and future findings based on contemporary 'omics based methods and future methods that are yet to be defined. The Code allows us to make assertions and to propose hypotheses that are supported by a wealth of experimental data that are directly comparable. It is important to also remember that nomenclature is one step in an information management system, the scope of which is only limited by the bounds of the methods available for studying the organisms themselves and our ability to interpret and comprehend that information.
In the preface to the 1990 Revision of the Code, P. H. A. Sneath indicated the influential role that the Code has had on developments in botany and zoology, which continues to be the case today. In his review of the preparation of the Approved Lists, Sneath [1]

At Iowa State College (ISC)
In 1910 Buchanan was appointed first head of bacteriology at ISC, and the same year married a botanist, Estelle Fogel, with whom he collaborated in writing the well-known Buchanan & Buchanan's Bacteriology. From 1914 to 1919 Buchanan was the first Dean of the Division of Industrial Sciences; from 1919 to 1948 he was the first Dean of the Graduate College, and from 1933 to 1948 Director of the Agricultural Experiment Station. When he retired officially in 1948 Buchanan was made "Emeritus" and continued to have an office in the bacteriology department until his death; from this, and another office he had in Curtiss Hall, he kept a watchful eye on what went on in ISC, and he never hesitated to express his views forcibly when things displeased him. Throughout his life he took a great interest in Iowa State College (later University) and the Agricultural Experiment Station, and even after retirement his opinions were sought, respected, and sometimes feared.
In the summer vacations he would retire to the shores of Birch Lake in Minnesota, where he owned some land. There were two cabins (one belonged to his brother) built by their own hands, and over his boathouse Earle had a large office from which he sent a steady flow of dictaphone sleeves to his staff in Ames. His only relaxations were fishing and telling long tales of his travels, particularly of those in Arab countries.
In the cabin he was able to cook his fish by electricity (he was a good cook) for the cabin had all "mod. cons." except internal doors, for which curtains substituted.
Nearly twenty years after he retired, Iowa State University built and named after him a hall of residence for 400 graduate students.
The Scientific Side of the Dean To his students Buchanan was always known as the Dean, and undoubtedly administration had been his forte in the prime of his life. It is hard to think of him working at a bench, but in 1918 he published a paper on the various phases of growing cultures [2]. Most of his work was concerned with nomenclature and he was happiest delving into old books and holding forth about names. Between 1916 and 1918 he published a series of ten papers with the general title (subject to some variation) of "Studies in [on] the nomenclature and classification of [the] bacteria." In 1918 he was President of the Society of American Bacteriologists (SAB) and was a member of the Winslow Committee whose two reports [3,4] completely changed ideas on the classification and nomenclature of bacteria.
Of his other early publications, Buchanan's General Systematic Bacteriology [5] is best known; it is a book of about 600 pages and gives a reasoned account of the names of bacterial genera and higher ranks. This book has become a classic and, because it is accurate and informative, it is still consulted.

International Committees and Congresses
In addition to being one of America's best-known bacteriologists at the age of 35, Buchanan became an international figure; he was sent by U.S. government departments and by FAO to several countries in the Middle East and to India to advise on agricultural matters. In a series of articles on past Presidents of the SAB, it was said of Buchanan that he was as well known a figure in Piccadilly as on the Ames campus.
In 1930 Buchanan presided over the bacteriology section of the Botanical Congress in Cambridge, and attended the first International Congress of Microbiology in Paris, where he became one of the founders of the Nomenclature Committee. During the second Congress an American-Canadian Committee was set up to draft a code of bacteriological nomenclature and, of course, Buchanan became its chairman. He prepared a mimeographed document of 119 pages showing, in parallel columns, the International Rules of Botanical Nomenclature and the suggested wording for a bacteriological code based on the Botanical Code. A revised version was considered at the third Congress, when Buchanan was made the first chairman of the newly formed Judicial Commission. Further revision of the draft code followed and a Proposed Bacteriological Code [6] was printed at Ames by ISC Press and circulated to members of the Nomenclature Committee for discussion at the fourth Congress. After amendment this Code was approved and published [7].
A minor but troublesome commitment Buchanan undertook was the setting up of an official publication for the Nomenclature Committee and the Judicial Commission. It had no financial backing but Buchanan secured help (a few hundred dollars) from UNESCO, encouragement from Iowa State College Press, and some printing from a small press about a hundred miles from Ames. But the world's most cumbersomely titled journal (The International Bulletin of Bacteriological Nomenclature and Taxonomy) was born and later, with a glossy cover, achieved respectability as the International Journal of Systematic Bacteriology, which Buchanan edited until 1970. Index Bergeyana and Bergey's Manual After Bergey's death his Manual was carried on by R. S. Breed, E. D. G. Murray, and others, who made tentative plans for Index Bergeyana, an annotated list of names of bacterial taxa. Before this could be started Breed died, and Buchanan was invited to become Chairman of the Bergey's Manual Trust, an office he held until his death. All his life Buchanan had collected names of bacteria of all ranks and the record cards occupied a whole room in the office suite at Curtiss Hall; this collection became the major part of Index Bergeyana [9] which could more appropriately have been named Index Buchananensis. There were many errors in the Index, some of fact, some of opinion on legitimacy, but it was a remarkable achievement. It was the work of a lifetime, but unfortunately it was published when the responsibilities of such a huge task pressed too heavily on an ageing man.
For the remaining years of his life preparations and plans for the eighth edition of Bergey's Manual occupied Buchanan's attention. He built up a team of strong-minded individualists who battled for several years with the problems leading to a new edition, and authors were chosen and invited to become contributors. Though he was interested primarily in the nomenclature, Buchanan never yielded a point and sometimes had authors and trustees tearing their hair at his insistence on a strict adherence to his beloved Code. With his attention focused on the names to be used in the Manual, his energies were dissipated on trivia; priority was always paramount, he was not concerned with usage or with the confusion that could arise when names were changed to conform with a strict application of the rules of nomenclature. As he aged and his judgments became less reliable, he became inconsistent and dogmatic; he found it difficult to understand numerical and computer approaches to bacterial classification, but this did not unduly concern him except when it might involve nomenclature, and then it might puzzle or even anger him.

CHAPTER 1. GENERAL CONSIDERATIONS General Consideration 1
The progress of bacteriology can be furthered by a precise system of nomenclature accepted by the majority of bacteriologists of all nations.

General Consideration 2
To achieve order in nomenclature, it is essential that scientific names be regulated by internationally accepted Rules.

General Consideration 3
The Rules which govern the scientific nomenclature used in the biological sciences are embodied in International Codes of Nomenclature (see Appendix 1 for a list of these Codes).

General Consideration 4
Rules of nomenclature do not govern the delimitation of taxa nor determine their relations. The Rules are primarily for assessing the correctness of the names applied to defined taxa; they also prescribe the procedures for creating and proposing new names.

General Consideration 5
This Code of Nomenclature of Prokaryotes applies to all Prokaryotes. The nomenclature of eukaryotic microbial groups is provided for by other Codes: fungi and algae by the International Code of Nomenclature for algae, fungi and plants; protozoa by the International Code of Zoological Nomenclature. The nomenclature of viruses is provided for by the International Code of Virus Classification and Nomenclature (see Appendix 1).

General Consideration 6
This Code is divided into Principles, Rules and Recommendations.
(1) The Principles (Chapter 2) form the basis of the Code, and the Rules and Recommendations are derived from them. (2) The Rules (Chapter 3) are designed to make effective the Principles, to put the nomenclature of the past in order and to provide for the nomenclature of the future. (3) The Recommendations (Chapter 3) deal with subsidiary points and are appended to the Rules which they supplement.
Recommendations do not have the force of Rules; they are intended to be guides to desirable practice in the future. Names contrary to a Recommendation cannot be rejected for this reason. (4) Provisions for emendations of Rules, for special exceptions to Rules, and for interpretation of the Rules in doubtful cases have been made by the establishment of the International Committee on Systematics of Prokaryotes (ICSP) and its Judicial Commission, which acts on behalf of the ICSP (see Rule 1b and Statutes of the International Committee on the Systematics of Prokaryotes). Opinions issued by the Judicial Commission become effective after receipt of ten or more favorable votes from Commissioners, but may be rescinded by the ICSP as provided in the ICSP Statutes. The official journal of the ICSP is the International Journal of Systematic and Evolutionary Microbiology (IJSEM), formerly International Journal of Systematic Bacteriology (IJSB), formerly the International Bulletin of Bacteriological Nomenclature and Taxonomy (IBBNT). (Some other journal could be specified by the ICSP if required. Such possible future specification is implicit in the use of "International Journal of Systematic and Evolutionary Microbiology" or "IJSEM" throughout this Code, but is not always repeated at each mention.) (5) Appendices are added to assist in the application of this Code (see Table of Contents). (6) Definitions of certain words used in the Code are provided. Such words are indicated in boldface type in the clause concerned, and they may be printed in boldface type elsewhere in this Code.
(3) Names applied to individual taxa. A taxonomic group is referred to throughout this Code as a taxon, plural taxa.
"Taxonomic group" is used in this Code to refer to any group of organisms treated as a named group in a formal taxonomy; it may or may not correspond to a category.
Examples: Name of a species, Pseudomonas (generic name) aeruginosa (specific epithet); name of a genus, Pseudomonas; name of a family, Pseudomonadaceae; name of an order, Pseudomonadales.
General Consideration 8 The International Code of Nomenclature of Prokaryotes is an instrument of scientific communication. Names have meaning only in the context in which they were formed and used.
Editorial Note. In the Bacteriological Code (1975 Revision) many examples were taken from names that lost their standing in nomenclature on publication of the Approved Lists of Bacterial Names [1]. These examples were retained in the Bacteriological Code (1990 Revision), but the majority of these examples have now been replaced (see minute 7, topic 2 (ii) of the San Francisco minutes of the Judicial Commission [2]), although some have been retained because they illustrate nomenclatural problems which have occurred in the past and may occur again, but which cannot always be illustrated by names that currently have standing under the present Code.
Note 2. (i) By circumscription is meant an indication of the limits of a taxon, (ii) by position is meant the higher taxon in which a taxon is placed when there may be alternatives (see also Rule 23a) and (iii) by rank is meant level in the hierarchial sequence of taxonomic categories.

Principle 9
The name of a taxon should not be changed without sufficient reason based either on further taxonomic studies or on the necessity of giving up a nomenclature that is contrary to the Rules of this Code.

Rule 1a
This revision of the International Code of Nomenclature of Bacteria supersedes all previous revisions of the Bacteriological Code and shall be known as the International Code of Nomenclature of Prokaryotes (see Appendix 1). It shall be cited as the Prokaryotic Code (2008 Revision) and will apply from the date of publication online (2015).

Rule 1b
Alterations to this Code can only be made by the ICSP at one of its plenary sessions. Proposals for modifications should be made in sufficient time to allow publication in the IJSEM before the next International Congress of Bacteriology and Applied Microbiology. For this and other Provisions, see the Statutes of the ICSP.

Rule 2
The Rules of this Code are retroactive, except where exceptions are specified.

Rule 3
Names contrary to a Rule cannot be maintained, except that the International Committee on Systematics of Prokaryotes, on the recommendation of the Judicial Commission, may make exceptions to the Rules (see Rule 23a and the Statutes of the ICSP).

Rule 4
In the absence of a relevant Rule or where the consequences of a Rule are uncertain, a summary in which all pertinent facts are outlined should be submitted to the Judicial Commission for consideration (see Appendix 8 for preparation of a Request for an Opinion).

Rule 5a
Definitions of the taxonomic categories will inevitably vary with individual opinion, but the relative order of these categories may not be altered in any classification.

Rule 5b
The taxonomic categories above and including species which are covered by these Rules are given below in ascending taxonomic rank. Those in the left-hand column should he recognized where pertinent; those in the right-hand column are optional. The Latin equivalents are given in parentheses.

Rule 5c
A species may be divided into subspecies, which are dealt with by the Rules of this Code (see Rules 13a-d). Variety is a synonym of subspecies; its use is not encouraged as it leads to confusion, and after publication of this Code the use of the term variety for new names will have no standing in nomenclature.

Rule 5d
Taxa below the rank of subspecies (infrasubspecific subdivisions) are not covered by the Rules of this Code, but see Rule 14a and Appendix 10.

Rule 6
The scientific names of all taxa must be treated as Latin; names of taxa above the rank of species are single words.

Recommendation 6
To form new prokaryotic names and epithets, authors are advised as follows.
(1) Avoid names or epithets that are very long or difficult to pronounce.
(2) Make names or epithets that have an agreeable form that is easy to pronounce when latinized.
(3) Words from languages other than Latin or Greek should be avoided as long as equivalents exist in Latin or Greek or can be constructed by combining word elements from these two languages. Exceptions: names derived from typical local items such as foods, drinks or geographical localities for which no Latin or Greek names exist. (4) Do not adopt unpublished names or epithets found in authors' notes, attributing them to the authors of such notes, unless these authors have approved publication. (5) Give the etymology of new generic names and of new epithets. (6) Determine that the name or epithet which they propose is in accordance with the Rules. (7) The Greek K and Z and the Medieval Latin J (for consonantic I) should be maintained to avoid confusion.
Examples: Akinetobacter instead of Acinetobacter, Acidijanus instead of Acidianus. (8) The abbreviation M.L. stands for "Medieval Latin" not "Modern Latin". For the latter, N.L. ("Neo Latin") is to be used. (9) When arbitrary names (see Rules 10a and 12c) are formed, this has to be indicated and such names have to be easy in spelling and pronunciation. (10) Authors should not name organisms after themselves or after co-authors. If genus names or specific epithets are formed from personal names they should contain only the untruncated family (rarely the first) name of one person.

Rule 7
The name of a taxon above the rank of genus up to and including order is a substantive or an adjective used as a substantive of Latin or Greek origin, or a latinized word. It is in the feminine gender, the plural number, and written with an initial capital letter.
In practice, such names are used alone and as substantives.
Example: A member of the Pseudomonadaceae.

Rule 8
The name of each taxon (covered by the Code) above the rank of order is a Latin or latinized word. The name of a class is in the neuter gender, the plural number and written with an initial capital letter. The name is formed by the addition of the suffix -ia to the stem of the name of the type genus of the type order of the class. The name of a subclass is in the feminine gender, the plural number and written with an initial capital letter. The name is formed by the addition of the suffix -idae to the stem of the name of the type genus of the type order of the subclass.

Rule 9
The name of a taxon between subclass and genus is formed by the addition of the appropriate suffix to the stem of the name of the type genus (see Rule 15). These suffixes are presented in Table 1.

Rule 10a
The name of a genus or subgenus is a substantive, or an adjective used as a substantive, in the singular number and written with an initial capital letter. The name may be taken from any source and may even be composed in an arbitrary manner. It is treated as a Latin substantive.

Recommendation 10a
The following Recommendations apply when forming new generic or subgeneric names.
(1) Refrain from naming genera and subgenera after persons quite unconnected with bacteriology or at least with natural science. (2) Give a feminine form to all personal generic and subgeneric names whether they commemorate a man or a woman (see Rule 63). (3) Avoid introducing into bacteriology as generic names such names as are in use in botany or zoology, in particular wellknown names. (See Appendix 9).

Rule 10b
Generic and subgeneric names are subject to the same Rules and Recommendations, except that Rule 10c applies only to subgeneric names.

Rule 10c
The name of a subgenus, when included with the name of a species, is placed in parentheses along with the abbreviation "subgen." between the generic name and specific epithet. When included, the citation should be inserted before closure of the parentheses.

Rule 12a
The name of a species is a binary combination consisting of the name of the genus followed by a single specific epithet.
If a specific epithet is formed from two or more words, then the words are to be joined. If the words were not joined in the effective publication, then the epithet is not to be rejected but the form is to be corrected by joining the words, which can be done by any author. If an epithet has been hyphenated, its parts should be joined. The name is considered to have been validly published and retains its standing in nomenclature.

Rule 12b
No specific or subspecific epithets within the same genus may be the same if based on different types (see Rules 13c, 40d and Section 9).

Rule 12c
A specific epithet may be taken from any source and may even be composed arbitrarily.
Example: thetaiotaomicron in Bacteroides thetaiotaomicron derived from a combination of the Greek letters theta, iota and omicron.
A specific epithet must be treated in one of the three following ways.
(1) As an adjective that must agree in gender with the generic name. Example: aureus in Staphylococcus aureus. (2) As a substantive (noun) in apposition in the nominative case.
Example: Desulfovibrio gigas or other names cited in Trüper and De'Clari [3]. (3) As a substantive (noun) in the genitive case.
Example: coli in Escherichia coli.

Recommendation 12c
Authors should attend to the following Recommendations, and those of Recommendation 6, when forming specific epithets.
(1) Choose a specific epithet that, in general, gives some indication of a property or of the source of the species.
(2) Avoid those that express a character common to all, or nearly all, the species of a genus.
(3) Ensure that, if taken from the name of a person, it recalls the name of one who discovered or described it, or was in some way connected with it, and possesses the appropriate gender (see Appendix 9). (4) Avoid in the same genus epithets which are very much alike, especially those that differ only in their last letters (see Rule 56a (4)). (5) Avoid the use of the genitive and the adjectival forms of the same specific epithet to refer to two different species of the same genus (see Rule 63). (6) If an ordinal adjective used for enumeration is chosen then they may include numbers up to ten.

Rule 13a
The name of a subspecies is a ternary combination consisting of the name of a genus followed by a specific epithet, the abbreviation "subsp." (subspecies), and finally the subspecific epithet.

Rule 13b
A subspecific epithet is formed in the same way as a specific epithet. When adjectival in form, it agrees in gender with the generic name.

Rule 13c
No two subspecies within the same species or within the same genus may bear the same subspecific epithet (see also Rules 12b and 40d).

Rule 13d
A subspecies that includes the type of the species must bear the same epithet as the species (see also Rules 40d and 45).

Rule 14a
The designations of the various taxa below the rank of subspecies are not subject to the Rules and Recommendations of this Code (for advice on their nomenclature, see Appendix 10).

Rule 14b
A Latin or latinized infrasubspecific designation may be elevated by a subsequent author to the status of a subspecies or species name providing that the resulting name is in conformity with the Rules. If so elevated, it ranks for purposes of priority from its date of elevation and is attributed to the author who elevates it, provided that the author who elevates it observes Rule 27.

Rule 15
A taxon consists of one or more elements. For each named taxon of the various taxonomic categories (listed below), there shall be designated a nomenclatural type. The nomenclatural type, referred to in this Code as "type", is that element of the taxon with which the name is permanently associated, whether as a correct name or as a later heterotypic synonym. The nomenclatural type is not necessarily the most typical or representative element of the taxon. The types are dealt with in Rules 16-22. Types of the various taxonomic categories are presented in Table 2.

Rule 16
The type of a taxon must be designated by the author at the time the name of the taxon is published in the IJSEM (see Rules 15,18a,b,f,21a,22,27(3)).
Note. Authors who intend to publish the name in the IJSEM with reference to a previous effectively published description under Rule 27 (2) are advised also to designate the type when publishing that description.
Note. If a previous effective publication does not designate a type then the type must be designated at the time of valid publication in IJSEM, in accordance with the Rules of this Code.

Rule 17
The type determines the application of the name of a taxon if the taxon is subsequently divided or united with another taxon.
Example: Ash et al. [5] proposed that the genus Bacillus be divided into the genera Bacillus and Paenibacillus, and the genus which contained the type species Bacillus subtilis must be named Bacillus.

Rule 18a
Whenever possible, the type of a species or subspecies is a designated strain.
The type strain is made up of living cultures of an organism, which are descended from a strain designated as the nomenclatural type. The strain should have been maintained in pure culture and should agree closely to its characters with those in the original description (see Chapter 4C). The type strain may be designated in various ways (see Rules 18b, 18c, and 18d).
(1) Until 31 December 2000, for a species (or subspecies) which has not so far been maintained in laboratory cultures or for which a type does not exist, a description, preserved specimen, or illustration (see also Rule 18f) may serve as the type. Example: Non-cultivated, Oscillospira guilliermondii Chatton and Perard 1913. (2) As from 1 January 2001, a description, preserved (non-viable) specimen, or illustration may not serve as the type.

Rule 18b Designation by original author
If the author in the effective publication of the name of a species or subspecies definitely designated a type strain, then this strain shall be accepted as the type strain and may be referred to as the holotype.
Rule 18c Designation as neotype If a strain on which the original description was based cannot be found, a neotype strain may be proposed.
A neotype strain must be proposed (proposed neotype) in the IJSEM, together with citation of the author(s) of the name, a description or reference to an effectively published description, and a record of the permanently established culture collection(s) where the strain is deposited (see also Note 1 to Rule 24a).
The author should show that a careful search for the strains used in the original description has been made and that none of them can be found. The author should also demonstrate that the proposed neotype agrees closely with the description given by the original author.
The neotype becomes established (established neotype) two years after the date of its publication in the IJSEM, provided that there are no objections, which must be referred within the first year of the publication of the neotype to the Judicial Commission for consideration.
Note. The term "strain" refers to the culture or subcultures of it, described in the original description. This is not restricted to the strain bearing the culture collection number mentioned in the valid publication, but refers to any culture knowingly derived from the original strain.
Example: Roop et al. [6] proposed a neotype strain (strain VPI S-17=ATCC 35980) for Campylobacter sputorum (Pr evot 1940) V eron and Chatelain 1973 (Approved Lists 1980) because the type strain Forsyth ER33 was no longer extant. Any objection has been referred and the neotype strain of Campylobacter sputorum is the strain VPI S-17=ATCC 35980.

Rule 18d
A strain suggested as a neotype but not formally proposed in accordance with the requirements of Rule 18c (suggested neotype) has no standing in nomenclature until formally proposed and established.

Rule 18e
If an original strain that should constitute the type of a species is discovered subsequent to the formal proposal or establishment of a neotype for that species, the matter shall be referred immediately to the Judicial Commission.

Rule 18f
If a description or illustration constitutes, or a dead preserved specimen has been designated the type of a species (Rule 18a(1)) and later a strain of this species is cultivated, then the type strain may be designated by the person who isolated the strain or by a subsequent author. This type strain shall then replace the description, illustration or preserved specimen as the nomenclatural type. The designation of a type strain in this manner must be published in the IJSEM, the authorship and date of priority of publication being determined by the effective and valid publication of the name by the original authors (Rule 24b).
Rule 18g Change in characters of type and neotype strains If a type or neotype strain has become unsuitable owing to changes in its characters or for other reasons, then the matter should be referred to the Judicial Commission, which may decide to take action leading to replacement of the strain.

Rule 19 Reference strains
A reference strain is a strain that is neither a type nor a neotype strain but a strain used in comparative studies, e.g. taxonomic or serological, or for chemical assay.
A reference strain has no standing in nomenclature, but it may, by subsequent action, be made a neotype.

Rule 20a
The nomenclatural type (see Rule 15) of a genus or subgenus is the type species, that is, the single species or one of the species included when the name was originally validly published. Only species whose names are legitimate may serve as types.

Rule 20b Designation by original author
If the author of the effective or valid publication of a generic or subgeneric name designated a type species, that species shall be accepted as the type species.
Rule 20c Genus with only one species If the genus when originally published included only one species, then that species is the type species.

Rule 20d Designation by a subsequent author
The type species shall be selected from one of the species included when the genus was originally published.

Recommendation 20d
Authors are recommended to exclude the following species from consideration in selecting the type.

Rule 20f Retention of type species on publication of a new generic name
The valid publication of a new generic name as a deliberate substitute for an earlier one does not change the type species of the genus.
Example: The deliberate creation of Xanthomonas as a substitute for the name Phytomonas (not available, as it was already in use as the name of a protozoan genus) does not change the type species, which was Phytomonas campestris and which became Xanthomonas campestris.

Rule 20g
A genus and its type subgenus share the same type species.
Example: Moraxella lacunata is the type species of the genus Moraxella and of its type subgenus, Moraxella.
Type of a Taxon from Genus to Order (Subtribe, Tribe, Subfamily, Family, Suborder, and Order)

Rule 21a
The nomenclatural type (see Rule 15) of a taxon above genus, up to and including order, is the legitimate name of the included genus on whose name the name of the relevant taxon is based. One taxon of each category must include the type genus. The names of the taxa which include the type genus must be formed by the addition of the appropriate suffix to the stem of the name of the type genus (see Rule 9).

Rule 21b
If the name of a family was not made in conformity with Rule 21a but its name has been conserved, then the type genus may be fixed by an Opinion of the Judicial Commission.
Example: The genus Escherichia is the type genus of the family Enterobacteriaceae (Opinion 15; Judicial Commission [10]).

Rule 22
The type (see Rule 15) of a taxon higher than order is one of the contained orders, and if there is only one order this becomes the type. If there are two or more orders the type shall be designated by the author at the time of the proposal of the name.
Example: The order Bacillales of the class Firmibacteria, or the order Verrucomicrobiales of the class Verrucomicrobiae.
If not designated, the type of a taxon higher than order may be later designated by an Opinion of the Judicial Commission.
Example: None of the Opinions so far issued (A-C, 1-96) has dealt with this subject.

Rule 23a
Each taxon above species, up to and including order, with a given circumscription, position, and rank can bear only one correct name, that is, the earliest that is in accordance with the Rules of this Code.
The name of a species is a binary combination of a generic name and specific epithet (see Rule 12a). In a given position, a species can bear only one correct epithet, that is, the earliest that is in accordance with the Rules of this Code.
Example: The species Haemophilus pleuropneumoniae bears this name in the genus Haemophilus. When placed in the genus Actinobacillus, it bears the name Actinobacillus pleuropneumoniae.
Note 1. In the case of a species, Rule 23a must be applied independently to the generic name and the specific epithet. The specific epithet remains the same on transfer of a species from one genus to another unless the specific epithet has been previously used in the name of another species or subspecies in the genus to which the species is to be transferred (see Rule 41a).
Note 2. The name of a subspecies is a ternary combination of a generic name, a specific epithet, and a subspecific epithet (see Rule 13c). In a given position a subspecies can bear only one correct subspecific epithet, that is, the earliest that is in accordance with the Rules of this Code. In the case of a subspecies, Rule 23a must be applied independently to the specific and subspecific epithets. The subspecific epithet remains the same on transfer of a subspecies from one species to another, unless the subspecific epithet has been previously used in the name of another species or subspecies in the genus to which the subspecies is to be transferred (see Rule 41a).  (1) By conserved name (nomen conservandum) is meant a name which must be used instead of all earlier synonyms and homonyms. By rejected name (nomen rejiciendum) is meant a name which must not be used to designate any taxon. Only the Judicial Commission can conserve or reject names (see also Rules 56a and 56b). Note 5. Names and epithets may be: legitimate-in accordance with the Rules; illegitimate-contrary to the Rules; effectively published-in printed and/or electronic matter made generally available to the scientific community (see Rule 25); validly published-effectively published and accompanied by a description of the taxon or a reference to a description and certain other requirements (see ; correct-the name which must be adopted for a taxon under the Rules.

Rule 23b
The date of a name or epithet is that of its valid publication. For purposes of priority, however, only legitimate names and epithets are taken into consideration (see Rules 32b and 54).

Rule 24a
Valid publication of names (or epithets) which are in accordance with the Rules of this Code dates from the date of publication of the Code.
Priority of publication dates from 1 January 1980. On that date all names published prior to 1 January 1980 and included in the Approved Lists of Bacterial Names are treated for all nomenclatural purposes as though they had been validly published for the first time on that date, the existing types being retained (but see Rule 24b).
Note 1. Names of prokaryotes in the various taxonomic categories published up to 31 December 1977 were assessed by the Judicial Commission with the assistance of taxonomic experts. Lists of names were prepared together with the names of the authors who originally proposed the names. These Approved Lists of Bacterial Names were approved by the ICSB and published in the IJSB on 1 January 1980. Names validly published between 1 January 1978 and 1 January 1980 were included in the Approved Lists of Bacterial Names (see Appendix 2).
No further names will be added to the Approved Lists. Those names validly published prior to 1 January 1980 but not included in the Approved Lists have no further standing in nomenclature. They were not added to the lists of nomina rejicienda and are thus available for reuse in the naming of new taxa. The reuse of a particular name cannot be recommended if such reuse is likely to result in confusion due to previous or continuing use of the name as a synonym, a strain designation, or for other reasons.
The Approved Lists of Bacterial Names contain for each name a reference to an effectively published description and the type whenever possible. In the case of species or subspecies, if a type strain is available it is listed by its designation and the culture collection(s) from which it may be obtained is indicated. If such a strain is not available, a reference strain or reference material is listed if possible. Neotypes may be proposed in conformity with Rule 18c on such lists. (For citation of names on the Approved Lists, see Rules 33b and 34a.) Note 2. These Approved Lists may contain more than one name attached to the same type (homotypic synonyms 1 ) since the names on the list represent those names which are considered reasonable in the present state of bacteriological nomenclature and taxonomy and represent the views of many bacteriologists who may hold different taxonomic opinions.
Note 3. Synonyms may be homotypic synonyms (i.e., more than one name has been associated with the same type) or heterotypic synonyms 2 (i.e., different names have been associated with different types that in the opinion of the bacteriologist concerned belong to the same taxon). The synonym first published is known as the earlier synonym 3 , and later synonyms are known as later synonyms 4 .
Publication of homotypic synonyms in the Approved Lists does not affect prokaryotic nomenclature any more than does the valid publication of homotypic synonyms in different works in the bacteriological literature at present.

Rule 24c
The Judicial Commission may place on the list of rejected names (nomina rejicienda) a name previously published in an Approved List.

Rule 25a Effective publication
Effective publication is effected under this Code by making generally available, by sale or distribution, to the scientific community, printed and/or electronic material for the purpose of providing a permanent record.
When a name of a new taxon is published in a work written in a language unfamiliar to the majority of workers in bacteriology, it is recommended that the author(s) include in the publication a description in English.
Note. Electronic publication should follow the tradition of publication of printed matter acceptable to this Code.

Rule 25b
No other kind of publication than that cited in Rule 25a is accepted as effective, nor are the following.

Rule 26a Date of publication
The date of publication of a scientific work is the date of publication of the printed and/or electronic matter. The date given to the work containing the name or epithet must be regarded as correct in the absence of proof to the contrary.

Rule 26b
The date of acceptance of an article for publication if given in a publication does not indicate the effective date of publication and has no significance in the determination of the priority of publication of names.

Rule 27
A name of a new taxon, or a new combination for an existing taxon, is not validly published unless the following criteria are met.
(1) The name is published in the IJSB/IJSEM.
(2) The publication of the name in the IJSB/IJSEM is accompanied by a description of the taxon or by a reference to a previous effectively published description of the taxon (see Rules 16, 25a and 25b and, for genus and species, Rules 29-32).
As of 1 January 2001 the following criteria also apply a. The new name or new combination should be clearly stated and indicated as such (i.e. fam. nov., gen. nov., sp. nov., comb. nov., etc.).
b. The derivation (etymology) of a new name (and if necessary of a new combination) must be given. c. The properties of the taxon being described must be given directly after (a) and (b). This may include reference to tables or figures in the same publication, or reference to previously effectively published work. d. All information contained in (c) should be accessible.
(3) The type of the taxon must be designated (see Rules 15,16,18a,b,f,21a and 22). In the case of species or subspecies including new combinations, the type strains must be deposited according to Rule 30. At the request of the Judicial Commission, the IJSB/IJSEM provides a Notification List which lists all nomenclatural changes as well as listing changes in taxonomic opinion that have occurred in an issue of the journal. This list has no formal status in prokaryote nomenclature except to allow for orthographic corrections to be made.
In the case of a name of a new taxon (rather than a new combination for a taxon already described), a type must be designated in the effective or valid publication. It is recommended that the type of a species or subspecies be deposited in a recognized culture collection [see Rule 30 (3a) and Rule 30 (3b)] and that the description of the taxon conform to minimal standards (see Recommendation 30).

Rule 28a
An author validly publishing a new name after 1 January 1980 may revive a name published prior to 1 January 1980 (see Rule 24a) but not listed in one of the Approved Lists of Bacterial Names unless the name is a nomen rejiciendum. The name may be used whether or not the new taxon is related in any way to the taxon to which the name was originally applied.
Authority for the name must be claimed by the new author. However, if the author wishes to indicate that the name is a revived name and is used to describe a taxon with the same circumscription, position, and rank as that given by the original author, this may be done by appending the abbreviation "nom. rev." (revived name) to the name (see Rule 33c).
The proposal must contain a brief diagnosis, i.e. a statement or list of those features that led the author to conclude that the proposed taxon is sufficiently different from other recognized taxa to justify its revival. The data included in the statement may be taken from the earlier description and may include newer data, when appropriate. The description of the taxon and derivation of the name must conform to the requirements of Rule 27 (2). The type must also be designated [see Rule 27 (3)].

Note 1.
A new name which was previously published before 1 January 1980 is only considered to be already validly published if the name was included in the Approved Lists of Bacterial Names.
Note 2. Since revived names are treated as new names, they require valid publication, and the date of priority of publication of a revived name is that of the publication in the IJSEM (see Rule 27).

Rule 28b
A name or epithet is not validly published in the following circumstances.  [16] stated: "Also, recently another organism tentatively named as Microcyclus marinus was isolated from the ocean." Valid Publication of the Name of a Genus or Subgenus, including a Monotypic Genus

Rule 29
For a generic or subgeneric name to be validly published it must comply with the following conditions.
(1) It must be published in conformity with Rules 27 and 28b.
(2) The genus or subgenus named must include one or more described or previously described species.
Instead of a new description of the genus or subgenus, a citation to a previously and effectively published description of the genus as a subgenus (or subgenus as a genus) may be given.
Example: Not yet found.
In the case of a genus containing a single species, a combined generic and specific description may be given.

Recommendation 29
A description of a genus or subgenus should mention the points in which the genus or subgenus differs from related genera or subgenera. Where possible, the family to which it belongs should be mentioned.

Rule 30
For the name of a species to be validly published, it must conform with the following conditions.
(1) It must be published in conformity with Rules 27 and 28b.
(2) It must be published as a binary combination consisting of a genus name followed by a single species epithet (see Rule 12a). (3) (a) Up to 31 December 2000, before publication of the name of a new species, a culture of the type strain (or, if the species is non-cultivable, type material, a photograph or an illustration, see Rule 18a) should be deposited in at least one of the permanently established culture collections from which it would be readily available. The designation allotted to the strain by the culture collections should be quoted in the published description. (b) As of 1 January 2001, the description of a new species, or new combinations previously represented by viable cultures must include the designation of a type strain (see Rule 18a), and a viable culture of that strain must be deposited in at least two publicly accessible culture collections in different countries from which subcultures must be available. The designations allotted to the strain by the culture collections should be quoted in the published description. Evidence must be presented that the cultures are present, viable, and available at the time of publication. Note. In exceptional cases, such as organisms requiring specialized facilities (e.g. Risk Group/Biological Safety Level 3, high pressure requirements, etc.), exceptions may be made to this Rule. Exceptions will be considered on an individual basis by a committee consisting of the Chairman of the ICSP, the Chairman of the Judicial Commission and the Editor of the IJSEM. Exceptions will be made known at the time of publication. (4) Organisms deposited in such a fashion that access is restricted, such as safe deposits or strains deposited solely for current patent purposes, may not serve as type strains.

Recommendation 30
Before publication of the name and description of a new species, the examination and description should conform at least to the minimal standards (if available) required for the relevant taxon of prokaryote.
Note 1. Lists of minimal standards are being prepared for each group of prokaryotes by experts at the request of the Judicial Commission for consideration by the Judicial Commission and the ICSP for publication in the IJSEM (see Appendix 6). Such standards include tests for the establishment of generic identity and for the diagnosis of the species, i.e. an indication of characters which would distinguish the species from others.

Note 2.
It is the aim of minimal standards to provide guidance on the description of taxa for taxonomists seeking such advice. However, these standards are not to be applied in such a way as to contradict Principle 1(4).

Rule 31a
The name of a species or a subspecies is not validly published if the description is demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name of a taxon.
Examples: (a) 'Methanobacillus omelianskii' Bryant et al. 1967, whose description included all component species, was treated as a single species and was thus illegitimate; (b) Syntrophobacter wolinii Boone and Bryant 1984 is legitimate, because the species description applies to one member of the syntrophic association with a hydrogen-producing organism.

Rule 31b
The name of a consortium is not regulated by this Code, and such a name has no standing in nomenclature.

Note.
A consortium is an aggregate or association of two or more organisms.

Rule 32a
For the name of a subspecies to be validly published, it must conform with the following conditions.
(1) It must be published in conformity with Rules 27 and 28b.
(2) It must be published as a ternary combination consisting of the generic name followed by a single specific epithet and this in turn by a single subspecific epithet, with the abbreviation "subsp." between the two epithets to indicate the rank (see Rule 13a). Example: Bacillus subtilis subsp. subtilis. (3) The author must clearly indicate that a subspecies is being named.

Recommendation 32a
Recommendation 30 applies to the name of a subspecies with replacement of the word "species" by the word "subspecies".

Rule 32b
A specific (or subspecific) epithet is not rendered illegitimate by publication in a species (or subspecies) name in which the generic name is illegitimate (see also Chapter 3, Section 8, and example for Rule 20f).

Rule 33a
An author should indicate that a name is being proposed for a new taxon by the addition of the appropriate abbreviation for the category to which the taxon belongs. Note 1. Appropriate abbreviations are: "ord. nov." for ordo novus, "gen. nov." for genus novum, "sp. nov." for species nova, "comb. nov." for combinatio nova. Similar abbreviations may be formed as required.
Note 2. Although words or abbreviations in Latin are usually printed in italics, such abbreviations as the above are frequently printed in Roman or boldface type when they follow a Latin scientific name in order to differentiate them from the name and draw attention to the abbreviation.

Rule 33b
The citation of the name of a taxon that has been previously proposed should include both the name of the author(s) who first published the name and the year of publication. If there are more than two authors of the name, the citation includes only the first author followed by "et al." and the year. Note 2. Full citation of the publication should include reference to the page number(s) in the main text of the scientific work in which the name was proposed, not to the summary or abstract of that text even if proposal of the name is mentioned in that summary or abstract.
Example: Bacillus subtilis (Ehrenberg 1835) Cohn 1872, 174. The page number "174" is the page in Cohn's publication [17] on which the proposal of the new combination occurs.

Rule 33c
If a name or epithet which was published prior to 1 January 1980 but not included in an Approved List is proposed by an author for a different or for the same taxon, the name or epithet must be attributed to the author of the proposal (Rule 28a), and the citation should be made according to Rules 33a, 33b, 34a and 34b.
Note 1. If a name or epithet is revived for the same taxon (in the author's opinion), the author may indicate the fact by addition of the abbreviation ''nom. rev.'' (nomen revictum) after the correct abbreviation (Rule 33a) for the category concerned.

Rule 33d
If a name is revived under Rule 33c it may be revived in a new combination; that is, the revived species may be transferred to another genus, or the revived subspecies may be transferred to another species, at the time the name is revived. It is not necessary first to revive the name in the original combination.

Rule 34a
When an author transfers a species to another genus (Rule 41), or a subspecies to another species, then the author who makes the transfer should indicate the formation of the new combination by the addition to the citation of the abbreviation ''comb. nov.'' (combinatio nova).
This form of citation should be used when the author retains the original specific epithet in the new combination; however; if an author is obliged to substitute a new specific epithet as a result of homonymy, the abbreviation ''nom. nov.'' (nomen novum) should be used [see Rule 41a (1)]. The original name is referred to as the basonym.

Rule 34b
The citation of a new combination which has been previously proposed should include the name of the original author in parentheses followed by the name of the author(s) who proposed the new combination and the year of publication of the new combination.

Rule 34c
When a taxon from subspecies to genus is altered in rank but retains its name or epithet, the original author(s) must be cited in parentheses followed by the name of the author(s) who effected the alteration and the year of publication. Citation of the Name of a Taxon whose Circumscription Has Been Emended

Rule 35
If an alteration of the diagnostic characters or of the circumscription of a taxon modifies the nature of the taxon, the author responsible may be indicated by the addition to the author citation of the abbreviation ''emend.'' (emendavit) followed by the name of the author responsible for the change.

Rule 36
A name conserved so as to exclude the type is not to be ascribed to the original author, but the author whose concept of the name is conserved must be cited as authority.
Example: The original type species of the genus Aeromonas was rejected as a nomen dubium. (Opinion 48; Judicial Commission [21]). The generic name Aeromonas is now attributed to Stanier 1943, not to Kluyver and van Niel 1936, and with a new type species, A. hydrophila.

Rule 37b
A change in the name of a taxon is not warranted by an alteration of the diagnostic characters or of the circumscription. A change in its name may be required by one of the following.

Rule 38
When two or more taxa of the same rank are united, then the name of the taxon under which they are united (and therefore the type of the taxon) is chosen by the rule of priority of publication.
Note. Eberthella was raised by Bergey et al. [24] to a genus from the subgeneric name, Eberthella Buchanan 1918.
If, however, this choice would lead to confusion in bacteriology, the author should refer this matter to the Judicial Commission. (For taxa above the rank of species, see also Rule 47a).
Example: Not yet found.

Rule 39a
If a genus is divided into two or more genera or subgenera, the generic name must be retained for one of these. If the name has not been retained (in a previous publication), it must be re-established under Rule 39b. (See Rule 49 when a subgenus is raised to genus).
Example: Ash et al. [5] proposed that the genus Bacillus be divided into the genera Bacillus and Paenibacillus, and the genus which contained the type species Bacillus subtilis must be named Bacillus.

Rule 39b
When a particular species has been designated as the type, the generic name must be retained for the genus which includes that species. When no type was designated a type must be chosen (Editorial Note: should not be needed in the future; see Rule 27).

Rule 39c
The principles of Rules 39a and 39b apply when a subgenus is divided into two or more subgenera, the original subgeneric name being retained for that subgenus which contains the type species.

Rule 40a
When a species is divided into two or more species or subspecies, the specific epithet of the original species must be retained for one of the taxa into which the species is divided or, if the epithet has not been retained (in a previous publication), it must be re-established. (See Rule 50a when a subspecies is elevated to a species).

Rule 40b
The specific epithet must be retained for the species or subspecies which includes the type strain. When no type was designated, one must be chosen.
Example: If the species Bacillus subtilis is divided into subspecies, the subspecies containing the type strain must be named Bacillus subtilis subsp. subtilis.

Rule 40c
The principles of Rules 40a and 40b apply when a subspecies is divided into two or more subspecies, the original subspecies name being retained for that subspecies which contains the type strain.
Note. Although the specific and subspecific epithets in the name of a type subspecies are the same, they do not contravene Rule 12b because they are based on the same type.

Rule 40d
The valid publication of a subspecific name which excludes the type of the species automatically creates another subspecies which includes the type and whose name bears the same specific and subspecific epithets as the name of the type.

Rule 41a
When a species is transferred to another genus without any change of rank, the specific epithet must be retained, or if it has not been retained (in a previous publication), it must be re-established, unless (see Rule 23a Note 1): (1) The resulting binary combination would be a later homonym. Example: Bernardet et al. [25] proposed Flavobacterium hydatis for Cytophaga aquatilis Strohl and Tait 1978 (Approved Lists 1980) on transfer to Flavobacterium because in that genus the name Flavobacterium aquatile already existed. (2) There is available an earlier validly published and legitimate specific or subspecific epithet.
Example: Not yet found.

Rule 41b
When the name of a genus is changed, the specific epithets of the species included under the original generic name must be retained for the same species if they are transferred to the new genus.

Rule 42
In the case of subspecies, species, subgenera, and genera, if two or more of those taxa of the same rank are united, the oldest legitimate name or epithet is retained.
If the names or epithets are of the same date, the author who first unites the taxa has the right to choose one of them, and his choice must be followed.

Recommendation 42
Authors who have to choose between two generic names of the same date should note the following: (1) Prefer the one which is better known.
(2) Prefer the one which was first accompanied by the description of a species.
(3) If both are accompanied by descriptions of species, prefer the one which includes the larger number of species.
(4) In cases of equality from these points of view, prefer the more appropriate name.

Rule 43
When several genera are united as subgenera of one genus, the subgenus which includes the type species of the genus under which union takes place must bear the same name as that genus.

Rule 44
If two or more species of different genera are brought together to form a genus, and if these species include the type species of one or more genera, the name of the genus is that associated with the type species having the earliest legitimate generic name.
If no type species is placed in the genus, a new generic name must be proposed and a type species selected.
Example: Brevibacterium Breed 1953. None of the included species was a type species of the genera from which the species were transferred, so a new name, Brevibacterium, was proposed, with Brevibacterium linens as the type species.

Rule 45
When several species are united as subspecies under one species, the subspecies which includes the type strain of the species under whose name they are united must be designated by the same epithet as the species.

Rule 46
Editorial Note. The former Rule 46 has been relocated as Rule 40d. This rule only remains here only as a placeholder in order to avoid renumbering Rules 47 and above. Rule 46 should not be cited.

Rule 47a
When two or more taxa of the same rank from subtribe to family inclusive are united under a taxon of higher rank, the higherranking taxon should derive its name from the name of the earliest legitimate genus that is a type genus of one of the lowerranking taxa.
If, however, the use of this generic name would lead to confusion in bacteriology, then the author may choose as type a genus which, in his opinion, leads to the least confusion and, if in doubt, should refer the matter to the Judicial Commission.
Note. The type of a taxon above the rank of genus is one of the contained genera (Rule 15). The name of the type subgenus is the same as that of the type genus; therefore, only the names of genera need to be considered.
Example: Buchanan in Breed et al. [28] followed the law of priority in combining the families Beggiatoaceae Migula 1894 and Vitreoscillaceae Pringsheim 1949 into the new order Beggiatoales, whose type is Beggiatoa Trevisan 1842, which has priority over Vitreoscilla Pringsheim 1949. In contrast, Breed et al.

Rule 47b
If no type genera were placed in the taxon, a new name based on the selected type must be proposed for the taxon.

Rule 48
When the rank of a taxon between subgenus and order is changed, the stem of the name must be retained and only the suffix altered unless the resulting name must be rejected under the Rules (see Rule 9).
Example: Elevation of the tribe Pseudomonadeae to the family Pseudomonadaceae.

Rule 49
When a genus is lowered in rank to subgenus, the original name must be retained unless it is rejected under the Rules. This also applies when a subgenus is elevated to a genus.

Rule 50a
When a subspecies is elevated in rank to a species, the subspecific epithet in the name of the subspecies must be used as the specific epithet of the name of the species unless the resulting combination is illegitimate.

Rule 50b
When a species is lowered in rank to a subspecies, the specific epithet in the name of the species must be used as the subspecific epithet of the name of the subspecies unless the resulting combination is illegitimate.

Rule 51a
A name contrary to a Rule is illegitimate and may not be used. However, a name of a taxon which is illegitimate when the taxon is in one taxonomic position is not necessarily illegitimate when the taxon is in another taxonomic position.
Example: If the genus Diplococcus Weichselbaum 1886 is combined with the genus Streptococcus Rosenbach 1884, Diplococcus is illegitimate as the name of the combined genus because it is not the earlier name. If the genus Diplococcus Weichselbaum is accepted as separate and distinct, then the name Diplococcus is legitimate.

Rule 51b
Among the reasons for which a name may be illegitimate are the following.
(1) If the taxon to which the name was applied, as circumscribed by the author, included the nomenclatural type of a name which the author ought to have adopted under one or more of the Rules. Example: If an author circumscribes a genus to include Bacillus subtilis, the type species of the genus Bacillus, then the circumscribed genus must be named Bacillus.
(2) If the author did not adopt for a binary or ternary combination the earliest legitimate generic name, specific epithet, or subspecific epithet available for the taxon with its particular circumscription, position, and rank.

Rule 52
The following are not to be regarded as specific or subspecific epithets.
(1) A word or phrase which is not intended as a specific epithet. Example: Bacillus nova species Matzuschita. (2) A word which is an ordinal adjective higher than ten used for enumeration.
Example: a in Bacillus a von Freudenreich.

Rule 53
An epithet is illegitimate if it duplicates a specific or subspecific epithet previously validly published for a species or subspecies of the same genus but which is a different bacterium whose name is based upon another type.
Example: Bacillus pallidus Scholz et al. 1988 is based on the nomenclatural type, strain H12; the specific epithet pallidus cannot be used for Bacillus pallidus Zhou et al. 2008, which is a different bacterium whose name is based upon another type.

Rule 54
A name or epithet illegitimate according to Rules 51b, 53 or 56a is replaced by the oldest legitimate name or epithet in a binary or ternary combination which in the new position will be in accordance with the Rules.
If no legitimate name or epithet exists, one must be chosen. Since a specific epithet is not rendered illegitimate by publication in a species name in which the generic name is illegitimate (Rule 32b), an author may use such an epithet if he wishes, provided that there is no obstacle to its employment in the new position or sense; the resultant combination is treated as a new name and is to be ascribed to the author of the combination. The epithet is, however, ascribed to the original author.
Example: Pfeifferella pseudomallei (Whitmore 1913) Ford 1928 is an illegitimate combination since Pfeifferella is a homonym of a protozoan generic name (Opinion 14; Judicial Commission [32]). The epithet pseudomallei can be used for this organism in another genus, Pseudomonas pseudomallei (Whitmore 1913) Haynes 1957.

Rule 55
A legitimate name or epithet may not be replaced merely because of the following.
Example: Not yet found. (4) Another name is better known.
Example: Corynebacterium pseudodiphtheriticum cannot be rejected because the synonym Corynebacterium hofmannii is better known. (5) It no longer describes the organism.
Example: Haemophilus influenzae (does not cause influenza). (6) It has been cited incorrectly; an incorrect citation can be rectified by a later author.

Rule 56a
Only the Judicial Commission can place names on the list of rejected names (nomina rejicienda) (see Rule 23a, Note 4, and Appendix 4). A name may be placed on this list for various reasons, including the following.
(1) An ambiguous name (nomen ambiguum), i.e. a name which has been used with different meanings and thus has become a source of error. Example: Aerobacter Beijerinck 1900 (Opinion 46; Judicial Commission [35]). (2) A doubtful name (nomen dubium), i.e. a name whose application is uncertain.
Note 1. This application is restricted to a proposed change in the specific epithet of a nomenspecies which is widely recognized as contagious, virulent, or highly toxigenic, for example, to that of a subspecies of a species having a different host range or a degree of contagiousness or virulence. If the Judicial Commission recognizes a high order of risk to health, or of serious economic consequences, an Opinion may be issued that the taxon be maintained as a separate nomenspecies, without prejudice to the recognition or acceptance of its genetic relatedness to another taxon.

Rule 56b
A conserved name (nomen conservandum) is a name which must be used instead of all earlier synonyms and homonyms.
Note 1. A conserved name (nomen conservandum) is conserved against all other names for the taxon, whether these are cited in the corresponding list of rejected names or not, so long as the taxon concerned is not united with another taxon bearing a legitimate name. In the event of union or reunion with another taxon, the earlier of the two competing names is adopted in accordance with Rules 23a and 23b.

Rule 57a
Any name or epithet should be written in conformity with the spelling of the word from which it is derived and in strict accordance with the rules of Latin and latinization. Exceptions are provided for typographic and orthographic errors in Rule 61 and orthographic variants in Rules 62a and 62b (see also Appendix 9).

Rule 57b
In this Code, orthographic variant means a name (or epithet) which differs from another name only in transliteration into Latin of the same word from a language other than Latin or in its grammatical correctness.

Rule 57c
When two or more generic names or two or more epithets in the same genus are so similar (although the words are from different sources) as to cause uncertainty they may be treated as perplexing names (nomina perplexa) and the matter referred to the Judicial Commission [see Rule 56a(4)].
Note 1. Orthographic variants may be corrected by any author.
Note 2. Perplexing names may be placed on the list of rejected names only by the Judicial Commission, because decisions on the status of names derived from different sources differing in one or more letters affect many well-known names in bacteriology.

Rule 58
When there is doubt about different spellings of the same name or epithet, or where two spellings are sufficiently alike to be confused, the question should be referred to the Judicial Commission, which may issue an Opinion as seems fit. If one of the spellings is preferred by the Judicial Commission, this spelling should be used by succeeding authors.

Rule 59
An epithet, even one derived from the name of a person, should not be written with an initial capital letter.

Rule 60
Intentional latinizations involving changes in orthography of personal names, particularly those of earlier authors, must be preserved.
Example: Chauveau has been latinized as Chauvoe, and Clostridium chauvoei is derived from Chauvoe.

Rule 61
The original spelling of a name or epithet must be retained, except typographic or orthographic errors. Original spelling does not refer to the use of an initial capital letter or to diacritic signs.
An unintentional typographical or orthographic error later corrected by the author is to be accepted in its corrected form without affecting the status and date of valid publication. It can also be corrected by a subsequent author who may or may not mention that the spelling is corrected, but the abbreviation ''corrig.'' (corrigendum) may be appended to the name if an author wishes to draw attention to the correction. Succeeding authors may be unaware that the original usage was incorrect and use the spelling of the original author(s). Other succeeding authors may follow the correction of a previous author or may independently correct the spelling themselves, but in no case is the use of corrig. regarded as obligatory. None of these corrections affects the status and date of valid publication.
Note. The liberty of correcting a name or epithet under Rules 61, 62a, and 62b must be used with reserve especially if the change affects the first syllable and above all the first letter of the name or epithet. Except for changes of gender in specific epithets when species are transferred to other genera (comb. nov.) no grammatical or orthographic corrections will be accepted for names on the Approved Lists of Bacterial Names, the Validation Lists and the Notification Lists.

Rule 62a
Words differing only in transliteration into Latin from other languages which do not use the Latin alphabet are to be treated as orthographic variants unless they are used as the names of taxa based upon different types, when they are to be treated as homonyms. For an account of possible orthographic variants, see Appendix 9.

Rule 62b
When there are orthographic variants based on the same type, and there is no clear indication that one is correct, then an author has the right of choice.

Rule 63
The genitive and adjectival forms of a personal name are treated as different epithets and not as orthographic variants unless they are so similar as to cause confusion. For the latinization of personal names, see Appendix 9.

Rule 64
Diacritic signs are not used in names or epithets in bacteriology.
In names or epithets derived from words with such signs, the signs must be suppressed and the letters transcribed as follows: (1) € a, ö; and ü become ae, oe, and ue; (2) e; e; andê become e; (3) ø, , and a become oe, ae, and aa, respectively.

Rule 65
The gender of generic names is governed by the following.
(1) A Latin or Greek word adopted as a generic name retains the classical gender of its language of origin. Authors are recommended to give the gender of any proposed generic name. Example: Sarcina (Latin feminine noun, a package). In cases where the classical gender varies, the author has the right of choice between the alternatives (but see Opinion 3 of the Judicial Commission [41] for the masculine gender of -bacter). Example: -incola the gender may be masculine or feminine. Doubtful cases should be referred to the Judicial Commission. Example: Not yet found.

CHAPTER 4. ADVISORY NOTES
A. Suggestions for Authors and Publishers Publishers of periodicals and books are requested to indicate the year, month, and day of publication either on the publication itself or, in the case of a periodical, on the succeeding number. This information, as well as the title of the periodical or book from which the paper is reproduced, should also be printed on separates, tear sheets, or reprints.
Separates or reprints should always bear the pagination of the periodical of which they form a part.
An author who describes and names a new taxon should indicate the rank of the taxon concerned and where possible the rank and name of the next higher taxon (e.g., the name of the family to which a new genus is allocated or the name of the order in which a new family is placed). The title of the work concerned should indicate that a new name is published even if the name itself is not quoted in the title. For scientific names of taxa, conventions shall be used which are appropriate to the language of the country and to the relevant journal and publishing house concerned. These should preferably indicate scientific names by a different type face, e.g., italic, or by some other device to distinguish them from the rest of the text.
The name of a genus should be spelled without abbreviation the first time it is used with a specific epithet in a publication and in the summary of that publication.
In a series of species names all belonging to the same genus, it is customary to abbreviate the name of the genus in all but the first species, even if it is the first mention of the succeeding species.
Later use of the name of the species previously cited usually has the name of the genus abbreviated, commonly to the first letter of the generic name.
If, however, species are listed belonging to two or more genera which have the same initial letter, the generic name should he used in full. (3) Use of "pro synon.," "ex," "non," and "sic."

B. Quotations of Authors and Names
a. When citing a name published as a synonym, the words "as synonym" or "pro synon." should be added to the citation. (For types of synonym, see Rule 24a.) Example: Pseudomonas pyocyanea pro synon. Pseudomonas aeruginosa b. When an author publishes a name from a manuscript of another author, or revives another author's name (Rule 33c, Note 2), whether as a synonym or not, the word "ex" should be used to connect the names of the two authors. The name of the author who publishes the name precedes that of the original author.
Example: Achromobacter xylosoxidans (ex Yabuuchi and Ohyama 1971) Yabuuchi and Yano 1981 nom. rev. A subsequent author citing this revived name would use the citation Achromobacter xylosoxidans (ex Yabuuchi and Ohyama 1971) Yabuuchi and Yano 1981 or Achromobacter xylosoxidans Yabuuchi and Yano 1981. c. When citing in synonymy a name invalidated by an earlier homonym, the citation should be followed by the name of the author of the earlier homonym preceded by the word "non," preferably with the date of publication added. Example: Achromobacter Yabuuchi and Yano 1981 (non Achromobacter Bergey et al. 1923) d. If a name or epithet is adopted with alterations from the form as originally published, including the use of a corrected spelling, the original spelling should be cited in any list of synonyms of the corrected name. The original spelling is followed by the term "sic" in parentheses to indicate that the original spelling is accurately cited. Example: Bacillus pantothenticus (sic). (4) Nomen nudum. In the citation of a bare name (nomen nudum), the status of the name should be indicated by adding "nom. nud.". Note. A bare name (nomen nudum) means a name published without a description or a reference to a previously published description. Example: Not yet found.

C. Maintenance of Type Strains
The utmost importance should be given to the preservation of the original "type" material on which the description of a new species or subspecies is based (see Rules 18a, 27 and 30).
Preserved and living specimens should be maintained in a bacteriological laboratory, more particularly in one of the permanently established culture collections, and a record of this fact should be included in the publication (see Rule 30).
Maintenance may be by a variety of methods, e.g., in a medium, in a host by passage, in cells or exudates, or in the frozen or dried state.
Every precaution should be taken to maintain such cultures with a minimum amount of change. Repeated subculture may lead to phenotypic or genotypic changes. International Code of Nomenclature for algae, fungi, and plants (ICN) 2 The first international rules governing botanical nomenclature were established in 1867 at the Fourth International Botanical Congress in Paris.
Conflicting rules of botanical nomenclature were published in 1906 (the "Vienna Rules") and 1907 (the American Code of Botanical Nomenclature). These were later reconciled in the "Cambridge Rules" of 1935.          It was agreed that while specific substantive names derived from names of persons may be written with a capital initial letter, all other specific names are to be written with a small initial letter. Note. This Opinion is revoked by Rule 59 of this Code, and Recommendation 27h of the 1958 and 1966 editions of the International Code of Nomenclature of Bacteria (and Viruses) stated: "A specific epithet, even one derived from the name of a person, should not be written with an initial capital letter."

Opinions issued by the Judicial Commission
Opinion Title Reference and notes 1 Result

1
The correct spelling of the specific epithet in the species name Bacillus megaterium de Bary 1884 1 (Part 1): 35-36 (1951) The spelling megaterium of the specific epithet in Bacillus megaterium de Bary is to be preferred to the spelling megatherium. (2) The bacterial family name Bacteriaceae is to be recognized as a nomen familiae rejiciendum (rejected family name). (2) The generic name Pseudomonas Migula 1894 is to be associated with the species designated and described by Migula 1895.
( was validly published and is legitimate as the name of the dysentery bacterium described by Shiga (1898).
(2) The specific epithet flexneri in the species name Shigella flexneri Castellani and Chalmers 1919 is designated as a conserved specific epithet (epitheton specificum conservandum) for the species first described as Bacillus dysenteriae Flexner 1900.
(3) The species name Shigella boydii Ewing 1949 was validly published and is legitimate. The specific epithet boydii in the species name Shigella boydii is to be conserved (epitheton specificum conservandum).  (1) Name of a hypothetical genus. A hypothetical genus is one in which no species is described, named, or cited; the existence of the genus is predicated upon the future discovery and description of species as yet unknown. A name applied to a hypothetical genus is not validly published and is to be placed in the list of nomina rejicienda.

Opinions issued by the Judicial Commission
(2) Name of a "temporary" genus. A generic name proposed for a genus whose sole function is stated to be to serve as the temporary generic haven for insufficiently described species, which species may be allocated later to an appropriate genus or genera, is to be regarded as not validly published. Such a name may be placed in the list of nomina rejicienda.
(3) Name of a new genus with a described species which is neither named nor identified with a previously named species.
A new generic name published in a combined description of a genus and species, without the species being named, without citation of a previously and effectively published description of the species, and without subsequent acceptance of the generic name and naming of the species by a later author, should be regarded as not validly published. Such a generic name may be placed in the list of nomina rejicienda. However, if a later author has recognized the generic name and has used it with a specific epithet in naming the species described by the first author, particularly if there has been later general acceptance of the name, there may be validation of the generic name as proposed by its author, with the name of the species ascribed to the later author who gave it. Proposals for such validations of names should be made to the Judicial Commission for appropriate action.

Opinions issued by the Judicial Commission
Opinion Title Reference and notes 1 Result simultaneous publication of the new binary combination of generic name and specific epithet. A published generic name applied to a new genus in which the generic name is not used in a binary combination in naming any species, but in which there is citation of a previously and effectively published description of a species under another name, is to be regarded as validly published and the consequent combinationes novae ascribed likewise to the author of the generic name.   (2) Names proposed in the above-listed publications of Tr ecul, Hallier, Billroth, and Ogston have in some cases been adopted by later authors as the names of bacterial taxa and one or other of the four authors named cited as author. In such cases the name of the taxon is to be ascribed to the first subsequent authors whose publication meets the requirements of valid publication as prescribed in the cont.

List of Opinions
Opinions issued by the Judicial Commission  ) and rejection of P. gallicida as an objective synonym of P. multocida (Editorial Note. As stated in the title and summary, the Opinion also confirms the nomenclatural types in the Approved Lists, but without prejudice to the powers of the Judicial Commission to amend them.) The names (Editorial Note. This should read "The types.") of the bacterial taxa cited in the Approved Lists of Bacterial Names are formally and explicitly confirmed as correct and supersede any others in use before the appearance of the lists but without prejudice to the powers of the Judicial Commission to amend them.  The attention of the Judicial Commission was drawn to issues relating to the use of names at the rank of class, subclass and order and the nomenclatural type of names at the rank of class and subclass that were not covered by Opinion 79. The Judicial Commission ruled that names at the rank of class and order proposed by Cavalier-Smith (Int. J. Syst. Evol. Microbiol., 52, 7-76, 2002) are to be placed on the List of Rejected Names (nomina rejicienda) and the use of names proposed in that publication above the rank of class is to be actively discouraged. In addition a list of names at the rank of class, subclass and order is given where the nomenclatural type, description or circumscription is unclear or where they otherwise appear to be not in accordance with the Rules of the International Code of Nomenclature of Bacteria.  (1) The name should be in the correct form. Generic and suprageneric names are single words in Latin form and spelled with an initial capital letter. Names of species are binary combinations of words in Latin form consisting of a generic name and a single, specific epithet, the latter spelled with an initial lowercase letter. Subspecific names are ternary combinations consisting of the name of a species followed by the term "subspecies" (ordinarily "subsp.") and this in turn by a single subspecific epithet. Names of taxa from the rank of order to tribe inclusive are formed by the addition of the appropriate suffix to the stem of the name of the type genus (see 5 below). The suffix for order is -ales, for suborder -ineae, for family -aceae, for subfamily -oideae, for tribe -eae, and for subtribe -inae.
Where possible, the title of the paper should include any new names or combinations that are proposed in the text.
(2) The name should be clearly proposed as a new name or combination and should be accepted by the author at the time of publication. New names are ordinarily proposed by an author appending the phrase "species nova" (abbreviation: sp. nov.), "genus novum" (abbreviation: gen. nov.), "combinatio nova" (abbreviation: comb. nov.), or the like after the name or combination that is being proposed as new; alternatively, the author may make a statement to the effect that a new name or combination is being introduced. Revival of names published prior to 1 January 1980 but not included in an Approved List may be effected by provisions in Rule 33; advice on this is also provided in a report by the Chair of the Judicial Commission (IJSB [1981] 31:678). A nomenclatural type is that constituent element of a taxon to which the name of a taxon is permanently attached. The type of a species or a subspecies is a strain, that of a genus is a species, and that of an order, family, subfamily, tribe, or subtribe is the genus on whose name the name of the higher taxon is based (see 1 above). The type of a taxon above the rank of order is one of the contained orders.
A type strain is one of the strains on which the author who first described a named organism based the description of the organism and which the author, or a subsequent author, definitely designated as a type.
A neotype strain replaces a type strain which can no longer be found. The neotype should possess the characteristics as given in the original description; any deviations should be explained. A neotype strain must be proposed by an author in the IJSEM (proposed neotype) together with a reference (or references) to the first description and name for the microorganism (or to an Approved List if appropriate), a description (or reference to a description) of the proposed neotype strain, and a record of the author's designation for the type strain and of at least two culture collections from which cultures of the strain are available. The neotype strain becomes established two years after the date of publication in the IJSEM (established neotype). Any objections should be referred to the Judicial Commission within the first year after publication of the proposal. A neotype strain shall be proposed only after a careful search for original strains. If an original strain is subsequently discovered, the matter shall be referred immediately to the Judicial Commission. Allowance is made for replacement of an unsuitable type strain.
(6) Descriptions of taxa should include the following information: (a) those characteristics which are essential for membership in the taxon, i.e., those characteristics which constitute the basic concept of the taxon; (b) those characteristics which qualify the taxon for membership in the next higher taxon; (c) the diagnostic characteristics, i.e., those characteristics which distinguish the taxon from closely related taxa; and (d) in the case of species, the total number of strains studied, the strain designations, and the number of strains which are either positive or negative for each characteristic. If the strains are not homogeneous in a characteristic, the specific strain numbers for those strains which disagree with the majority should be given. From this information, the detailed results for each strain can be reconstructed without the full publication of the details for each strain. Where appropriate, suitable photomicrographs and, if necessary, electron photomicrographs should be included as part of the description to show morphological or anatomical characters that are pertinent to the classification. Descriptions should conform at least to such minimal descriptions as have been approved (see Appendix 6).

APPENDIX 8. PREPARATION OF A REQUEST FOR AN OPINION
In those cases where strict adherence to the rules of nomenclature would produce confusion or would not result in nomenclatural stability, exceptions to the rules may be requested of the Judicial Commission of the ICSP. Requests for Opinions must be accompanied by a fully documented statement of the relevant facts. The Judicial Commission will consider all Requests for Opinions and should issue an Opinion in the IJSEM whether or not the proposal is accepted. The title of a manuscript should provide a concise statement of the contents of the manuscript. If an opinion of the Judicial Commission is requested in the text, "Request for an Opinion" should appear as a subtitle. When a request is not supported by adequate evidence, it will be returned to the author for revision. A Request for an Opinion submitted in an acceptable form will be published as soon as possible in the IJSEM, and microbiologists are invited to submit statements in support of or in opposition to the Request. When an Opinion is challenged, the basis of the challenge should be stated and supported by a documented statement of the relevant facts.
Requests for Opinions or challenges of such Requests or proposals for Opinions or of an issued Opinion should be submitted in a form suitable for publication without delay in the IJSEM.
C. Specific (and Subspecific) Epithets (1) Rule 12c of the Code demands that specific (or subspecific) epithets must be treated in one of the three following ways: (a) as an adjective that must agree in gender with the generic name; (b) as a substantive (noun) in apposition in the nominative case; (c) as a substantive (noun) in the genitive case.
(2) Adjectives and participles as specific epithets (a) Latin adjectives belong to the 1st, 2nd or 3rd declension. Those of the 1st and 2nd declension have different endings in the three genders. In the 3rd declension the situation is more complicated, as there are adjectives that don't change with gender, others that do and some that are identical in the masculine and feminine gender and different in the neuter. Table 1 gives some examples. Note that comparative adjectives are also listed. It is recommended always to look up an adjective in a dictionary before using it for the formation of a name. (b) Participles are treated as if they are adjectives, i.e. they fall under Rule 12c (1) of the Code. (c) Infinitive (also named 'present') participles in the singular do not change with gender. According to the four conjugations of Latin they end in -ans (first conjugation, e.g. vorans devouring, from vorare to devour, voro I devour), -ens (second conjugation, e.g. inhibens inhibiting, from inhibere to inhibit, inhibeo I inhibit), -ens (third conjugation, e.g. exigens demanding, from exigere to demand, exigo I demand), -iens (third conjugation, e.g. faciens making, from facere to make, facio, I make), -iens (fourth conjugation, e.g. oboediens obeying, from oboedire to obey, oboedio I obey).
Note. Knowledge of the ending of the first person singular in the present is decisive. (d)Perfect participles change their endings with gender and are handled like adjectives of the first and second declension, e.g. aggregatus (masc.), aggregata (fem.), aggregatum (neut.) (aggregated, from aggregare to get together), flexus, flexa, flexum (bent, from flectere to bend), latus, lata, latum (carried, from the irregular verb ferre to carry), diminutus, diminuta, diminutum (smashed, from diminuere to smash). (3) Nominative nouns in apposition as specific epithets (a) Nominative nouns in apposition must make sense to be acceptable. In grammar, apposition means 'the placing of a word or expression beside another so that the second explains and has the same grammatical construction as the first'; i.e. the added nominative noun has an explanatory specifying function for the generic name, thus, e.g. Desulfovibrio (f) In cases of very frequent family names where the honoured person is not easily identifiable, first and family name may be contracted without connecting vowel or hyphenation, but otherwise treated like a single family name. Examples: Owenweeksia, Elizabethkingia.
*This name of Lithuanian origin is not a genuine Latinized name. If it were, the genus names 'Zeikia' or 'Zeik(i)ella' might have been possible.
(4) Personal names in specific epithets (a) To form specific epithets from personal names there are principally two possibilities: the adjective form and the genitive noun form. The adjective form has no means to recognize the sex of the honoured person, which, in principle, is not necessary for nomenclatural purposes. The personal names receive appropriate endings according to the gender of the generic name as indicated in Table 3. Thus an adjective epithet is formed that has the meaning of 'pertaining/ relating/belonging to... (the person)'. (b) When the genitive of a Latinized personal name is formed for a specific epithet, the sex of the person to be honoured may be taken into consideration as indicated in Table 4. On the basis of classical, medieval and Neo-Latin usage, any of the forms of Latinization listed in Table 4 may be chosen. As evident from Table 4, the formation of specific epithets from personal names as genitive nouns poses certain problems only with names ending in -a and -o.

E. Formation of Prokaryote Names from Geographical Names
(1) The formation of prokaryote names from geographical names has no geopolitical meaning, i.e. such names cannot be used to express geopolitical claims. (2) Unlike epithets derived from personal names, epithets on the basis of geographical names cannot be formed as substantives in the genitive case. They must be adjectives and are usually constructed by adding the ending -ensis (masculine or feminine gender) or -ense (neuter gender) to the geographical name in agreement with the latter's gender.
Only if the name of the locality ends in -a or -e or -en, these letters are dropped before adding -ensis/-ense (e.g. jenensis from Jena, californiensis from California, drentensis from Drente, bremensis from Bremen). If the locality's name ends in -o, the ending becomes -nensis/-nense (e.g. the name of the Japanese city Sapporo: sapporonensis, sapporonense).

F. Formation of Names for Prokaryotes Living in Association or Symbiosis with Other Biota
(1) For the formation of names for prokaryotes that live in association or symbiosis with plants, fungi, animals or other prokaryotes it is important to know the exact meaning of the nomenclatural name of such a partner and how it was formed (adjective, genitive noun, etc.). (2) The easiest way of forming such specific epithets is the use of the genitive case of the generic name of the associated organism in question, e.g. suis, equi, bovis, muscae, muris, aquilae, falconis, gypis, elephantis (of the pig, horse, cow, fly, mouse, eagle, falcon, vulture, elephant), or fagi, quercus (4th declension genitive, spoken with long u), castaneae, aesculi, rosae, liliae (of the beech, oak, chestnut, horse chestnut, rose, lily). G. Names Originating from Languages Other than Latin or Greek Only Latin gender endings are permitted. Greek endings must be transformed into Latin endings. Example: The formation of the epithet simbae from the East African Swahili word simba, lion, for a Mycoplasma species was not necessary because in this genus the corresponding Latin epithet leonis (of the lion) had not been used before. (2) When it becomes unavoidable to use a word from another language the word stem must be identified before Latinization. Example: The Arabic word 'alkali' (al-qaliy, the ashes of saltwort) from which the element kalium (K; English, potassium) received its name. As the -i at the end of the word belongs to the stem it is wrong to speak and write of alcalophilic instead of alkaliphilic microbes. (3) Typical usages of the other language should not be carried over into Latin.
Example: The English suffix -philic (e.g. hydrophilic: friendly to water, water-loving) is an English transformation of the Latin -philus, -a, -um (originating from Greek philos, friendly). Therefore the ending -philicus must be avoided and -philus be used instead.
(4) National foods or fermentation products (e.g. sake, tofu, miso, yogurt, kvas, kefir, pombe, pulque, aiva, etc.) often do not have equivalent Latin names and if typical micro-organisms found in them or causing their fermentations are described, they may be named after them. These names cannot be used unaltered just as specific epithets in the form of nominative substantives in apposition. They are properly Latinized by forming a neuter substantive from them by adding -um (e.g. sakeum, tofuum, kefirum, pombeum, etc.) and the use of the genitive of that (ending -i) in the specific epithet (e.g. sakei, tofui, kefiri, pombei, etc.).

H. Formation of Prokaryote Names from Names of Elements and Compounds Used in Chemistry and Pharmacy
(1) The vast majority of names of chemicals are Latinized as neuter nouns of the 2nd declension with nominatives ending -um, genitives in -i. The following groups belong in this category: (a) Most of the chemical elements with the exception of carbon (L. carbo, carbonis) phosphorus (L. phosphorus, phosphori) and sulfur (L. sulfur, sulfuris) have the ending -(i)um with the genitive ending in -(i)i; nitrogen may also be called azotum besides nitrogenium, calcium may also be called calx (genitive calcis). (b) Names of chemical and biochemical compounds ending in -ide (including anions), -in, -ane, -ene, -one, -ol (only non-alcoholic compounds), -ose (sugars), -an (polysaccharides) and -ase (enzymes) are Latinized by adding the ending -um or by replacing the -e at the end by -um as appropriate. (c) Acids are named by acidum (L. neuter noun, acid), followed by a descriptive neuter adjective, e.g. sulfurous acid acidum sulfurosum, sulfuric acid acidum sulfuricum, acetic acid acidum aceticum. Latinized to -is, with the genitive -itis, e.g. nitrite becomes nitris, nitritis. The English ending -ate is Latinized to -as, with the genitive -atis, e.g. nitrate becomes nitras, nitratis. (4) Only a few chemicals have names that are Latinized in the 1st declension as feminine nouns, ending in -a with a genitive in -ae. Besides chemicals that always had names ending in -a (like urea), these are drugs found in classical and medieval Latin, such as gentian (gentiana) and camphor (camphora), and further modern drugs, whose Latin names were formed by adding -a, like the French ergot becoming ergota in Latin. An important group of this category are alkaloids and other organic bases, such as nucleic acid bases and amino acids with English names ending in -ine.
In Neo-Latin this ending is -ina, with the genitive -inae. Examples: betaina, -ae; atropina, -ae; adenina, -ae; alanina, -ae. (5) Names of pharmaceutical and chemical products or their registered or unregistered trade names are Latinized following the instructions given above. (6) For their use in prokaryote generic names and specific epithets, word stems and genitives of Latinized chemical names are the basis. In principle they are then treated like any other word elements.

I. Arbitrary Names
(1) The basis for arbitrary names are Rules 10a and 12c of the Code: 'genus names or specific epithets may be taken from any source and may even be composed in an arbitrary manner'. They must, however, be treated as Latin. (2) When proposing arbitrary names or epithets, authors should aim at short, elegant, easily spelled and pronounced ones.
Note. With arbitrary genus names the gender must also be indicated.

APPENDIX 10. INFRASUBSPECIFIC SUBDIVISIONS
The designations of these taxa are not covered by the Rules of this Code, but this Appendix is included to encourage conformity and to clarify the application of these designations (see Rule 14a, b).

A. Definitions
The term infrasubspecific subdivision (or division) has been used in two ways to denote both terms and taxa. It is preferable to distinguish them as given below. Infrasubspecific "subdivision" has been used rather than "division" to avoid any confusion with the taxonomic category "division" (divisio).
Note. Infrasubspecific subdivisions are not arranged in any order of rank, and may overlap one another.
(1) Infrasubspecific taxa. An infrasubspecific taxon is one strain or a set of strains showing the same or similar properties, and treated as a taxonomic group.
The sets of properties used may be of a similar kind but are not necessarily the same.
Example: The susceptibility to a different phage may be used to define another phagovar of Staphylococcus aureus, e.g., phagovar 42D.
Infrasubspecific taxa based on different sets of properties may overlap; e.g., one serovar may contain strains belonging to different phagovars.
(2) Infrasubspecific terms. An infrasubspecific term is used to refer to the kinds of taxa below subspecies.
If a species has not been divided into subspecies, the infrasubspecific terms may be applied to other subdivisions within that species. The subdivisions so named would still be infrasubspecific subdivisions for nomenclatural purposes until such time as they may be raised to subspecific or specific rank.
(3) Use of other terms. Infrasubspecific form has been used to refer to a bacterial strain, but this use should be avoided.
A culture of bacteria is a population of bacterial cells in a given place at a given time, e.g., in this test tube or on that agar plate. It may have a longer duration, e.g., desiccated cultures.
A clone is a population of bacterial cells derived from a single parent cell.
A strain is made up of the descendants of a single isolation in pure culture. A strain is usually made up of a succession of cultures and is often derived from a single colony. The number of bacteria which gave rise to the original colony is often unknown. Most bacterial strains are not known to be clones.
Individual is a term with little meaning in bacteriology and has been applied to a single bacterial cell or to a bacterial strain; therefore, it is best to avoid the use of this term. Table 1 contains some of the terms which are commonly used, and the preferred name appears in the first column. The introduction of the suffix "-var" or "-form" to replace "-type" is recommended to avoid confusion with the strict use of the term "type" to mean nomenclatural type (see Rule 15).

B. Infrasubspecific Terms
The term "type" in bacteriology should be used strictly for a nomenclatural type (Principle 5 and Chapter 3, Section 4). It should not be used to designate a division of a species nor to designate taxa based on antigenic characters.
The term "group" is informal and has no nomenclatural standing. It may prove useful to designate informally a set of organisms having certain characteristics in common, provided that it is used with care and exact definition to avoid ambiguity. It should not be used to avoid the use of the correct name of a taxon such as genus or species.
However, it may be useful when the bacteriologist does not wish to give a formal name to a set of bacteria until further studies have been made but wishes to publish his results and seek the opinion of others.

C. Nomenclature of Infrasubspecific Taxa
An infrasubspecific taxon is designated or cited by the name of the species followed by the infrasubspecific term used to designate this infrasubspecific subdivision followed by the infrasubspecific designation.
Reference strains of infrasubspecific taxa may be designated.
D. Nomenclature of Strains A strain may be designated in any manner, e.g., by the name of an individual, by a locality, or by a number. 1999-2002 van Niel Prize recipient, L. Wayne The committee's nomination for this session was L. Wayne (USA) for his contribution to the biology of Mycobacterium and to bacterial systematics in general. L. Wayne was duly awarded the van Neil Prize. The announcement was made during the IUMS Congress, and the Committee extended their congratulations to L. Wayne on this much-deserved award.

APPENDIX 13. ACTIVITIES OF THE CONGRESSES
The minutes of the meetings of the International Congress for Microbiology (and later, the International Congress of Bacteriology and Applied Microbiology) of the International Union of Microbiological Societies contain a detailed history of the evolution of this code of nomenclature. This appendix contains a summary of the activities of each congress and special meetings of the Judicial Commission. Following each summary is a bibliography of all references cited. Prior to the Sixth International Congress for Microbiology, the official record is contained here and in the first issue of the International Bulletin on Bacterial Nomenclature and Taxonomy. Conference proceedings have also been cited in retrospect, as they may contain more details on early unpublished work on the Code.

First International Congress for Microbiology
Paris, France 1930 The desire that special attention should be paid to the peculiar needs of bacteriology was voiced at the First International Several resolutions prepared by the Commission were approved unanimously by the Plenary Session. These resolutions (in their English text) were as follows: (I) The founding of the International Society for Microbiology and the establishment of Congresses of Microbiology make possible for the first time adequate international cooperation relative to certain problems of microbial nomenclature. It is clearly recognized that the living forms with which the microbiologists concern themselves are in part plants, in part animals, and in part primitive. It is further recognized that insofar as they may be applicable and appropriate the nomenclatural codes agreed upon by international Congresses of Botany and Zoology should be followed in the naming of microorganisms. Bearing in mind however the peculiarly independent course of development that Bacteriology has taken in the past fifty years and elaboration of special descriptive criteria which bacteriologists have of necessity developed, it is the opinion of the International Society for Microbiology that the bacteria constitute a group for which special arrangements are necessary. Therefore, the International Society for Microbiology has decided to consider the subject of Bacterial Nomenclature as part of its permanent programme. (II) The International Society for Microbiology is of the opinion that the interests of bacterial nomenclature will best be served by placing the subject in the hands of a single International Committee, under the aegis of the International Society for Microbiology, adequately representative of all departments of Bacteriology, on which experts from all spheres of bacteriological research may work together. It is recognized that the subject of bacterial nomenclature is of so wide a nature that unless the personnel of an International Committee formed to deal with it is representative of all aspects of bacteriology, it is not likely to carry weight. Such a representative committee, to be called the Nomenclature Committee for the International Society for Microbiology, is hereby authorized and constituted. (III) The Nomenclature Committee for the International Society for Microbiology shall be constituted as follows: (a) Two permanent secretaries shall be elected: one primarily to represent medical and veterinary bacteriology, the other primarily to represent the other phases of bacteriology. The following individuals are hereby appointed secretaries. Society and by such of the various National Societies affiliated with the International Society as may desire representation thereon. Not more than three members may be thus chosen to represent a single nation. In addition, in order that the Committee shall be truly representative of all interests, the Committee is authorized to add such members as may be deemed desirable. (IV) The duties of the Nomenclature Committee shall include the following: (a) Through the secretaries the members of the Committee shall be circularized with reference to such problems of bacterial nomenclature as may arise, and shall endeavor to reach an agreement. No action relating to nomenclature shall be considered complete and operative until it has been considered by all members of the Committee, until adequate publicity has been given with respect to actions proposed, until approval has been given by a majority of two thirds of the members of the Committee, and until a report has been made to the next succeeding International Congress for Microbiology and opportunity thereby given for objection, modification or rejection by action of the Congress. (b) The Committee shall consider, among others, problems such as criteria to be employed in classification, adoption of names for species and genera conservanda, type species (including their identification and preservation), the encouragement of monographing of special groups or genera of bacteria by those best qualified to do the work, the enlargement of the scope and usefulness of the various type culture collections by more adequate support, and the preparation and publication of such Committee and Subcommittee reports as may be advisable. (V) Copies of these resolutions shall be submitted to the appropriate sections of the International Botanical Congress, Cambridge, 1930. It is the hope of the International Congress for Microbiology that the members of the International Botanical Congress who are interested in bacterial nomenclature will see the advisability of the special questions of nomenclature of bacteria being considered by a single international authority and that they will suggest names of members of the Botanical Congress willing to serve on the committee who, in their opinion, would add to its strength and authority. (VI) In view of the adequate provision made for special regulations relating to the bacteria, and the feasibility of designating genera conservanda among the bacteria by international agreement, it is believed that the greatest stability will be conferred by the adoption of the publication of Species Plantarum by Linnaeus in 1753 as the point of departure for bacterial nomenclature. The adoption of this date is recommended. It is further suggested that no present action be taken with reference to a list of genera conservanda for the bacteria. (VII) Among the most important agencies working toward satisfactory nomenclature and classification of bacteria are the several type culture collections. These constitute invaluable repositories and much of the future development of bacteriology will depend upon their adequate growth, support and utilization; in some cases at least they should develop into research institutes of high grade. It is urged that the coordination and cooperation existing among these institutions be extended the better to serve the interests of bacteriology in its theoretical, medical and other economic aspects. It is further urged that all bacteriologists publishing descriptions of new species or important strains of bacteria deposit pure cultures of such with a culture collection that they may be made available to others interested. Particularly is it urged that the adequate financial support of these culture collections by official agencies, by educational and research institutions and by the research foundations constitutes an important and immediate need.
It will be noted that in the action of the A further specific action of the Nomenclature Committee and of the London Congress had to do with the duplication of generic names in the Protista, the group ordinarily defined to include the protozoa, algae, fungi and bacteria. Inasmuch as bacteria are usually included among the plants, and subsequent plant homonyms are regarded as illegitimate, the principal interest is the suppression as illegitimate later homonyms in the protozoa and the bacteria. Prof. F. Mesnil proposed and the Nomenclature Committee and the Congress agreed that generic homonyms are not permitted in the group Protista; further that it is advisable to avoid homonymy amongst Prostita on the one hand, plants or animals (Metazoa) on the other.
The Committee and Congress also acted favorably on a proposal by Prof. R. S. Breed relative to non-capitalization of specific epithets in names of species of bacteria.

Ninth International Congress for Microbiology Moscow, Union of Soviet Socialist Republics 1966
The Moscow Congress marked a change of direction in the philosophy of bacterial nomenclature. Change was in the air, and this is illustrated by the decision of the virologists (represented by the Subcommittee on Viruses of the International Committee on Nomenclature of Bacteria) to prepare their own rules of nomenclature. This led to the establishment at the Moscow Congress of a separate International Committee on Nomenclature of Viruses. This move was largely due to the feeling that viruses were of such a special nature that a new and different system of nomenclature should be introduced, and partly because Linnaean binary names were considered to be inappropriate [1][2][3]. The first report of the Virus Committee was published in 1971 [4]. At the Moscow Congress, the Judicial Commission was presented with a considerable list of proposed changes to the Bacteriological Code [2,3,5], of which the most lengthy were proposals to regulate the nomenclature of infrasubspecific forms, forms that had previously been subject only to recommendations on good practice. These proposals had, at Montreal, been deferred for further study, and it now became evident that they posed many difficulties that could not be avoided without consultation with epidemiologists, geneticists, biochemists, and others. These proposals were again referred back for further study.
The Commission discussed again the need for the regulation of names of sections, subsections, series and subseries. It became clear that these categories were used almost only within one genus, Streptomyces, whose taxonomy and nomenclature were increasingly at odds with modern practice in the rest of bacteriology. A feeling grew that it was a retrograde step to recognize complex rules for such categories if their need was diminishing, as awareness grew that many forms recognized as separate species of Streptomyces were more likely to be infrasubspecific variants. At its next meeting, the Commission agreed to remove from the Code the provisions that controlled the names of these categories, and this has been done in the present Code.
The revisions made at Moscow made it necessary to publish a new edition of the Code [6].
The question of old and useless names was considered at length. The device used by the Zoological Code-whereby names disused for 50 years could be considered to be forgotten names (nomina oblita) and thereafter ignored-was not thought useful. There was the risk of discovering later that such a name had been used in this period, thus necessitating reinstatement.
Another suggestion was that there should be block conservation of well-established names in certain publications of international repute. This had the disadvantage that much detailed taxonomic work would be required before such names could be conserved, and that there would be numerous appeals where the publications were perpetuating obvious errors.
The idea of a new starting date was then discussed. Similar suggestions had been raised in the past, but the important innovation was the proposal that an Approved List be prepared containing all names of taxa with current usage, and that at some given date in the future all other names should lose their standing in nomenclature. The Approved List would then be the basis for the nomenclature of the future. It was realized that the object of the change would be defeated if the old names were not available for re-use, because search of literature would still have to be made to avoid earlier homonyms, but on closer examination it was felt that the re-use of old names should not lead to major confusion. In the event, this radical proposal was accepted and is thought to be workable [2]. Only a few changes were made to the Code, mostly of an editorial nature [1][2][3]. The application of Rules 16 and 27, dealing with validation of names effectively published outside the IJSB, was clarified.
A proposal was published that the Cyanobacteria (Blue-Green Algae) should come under the provisions of the Bacteriological Code [4]. This was discussed at length by the Judicial Commission and the ICSB. There are difficulties in reconciling the application of the Bacteriological and Botanical Codes to these organisms, the great majority of which have been studied and named according to botanical precedent. Few of them are yet in culture, and the Botanical Code has not permitted living types (i.e., type cultures). It was therefore decided to refer the matter to the officers of the Botanical Code, with whom discussion continues, and it is hoped that a satisfactory conclusion may be reached in due course. Meanwhile it was noted [2] that workers who consider cyanobacteria to be bacteria may name them in accordance with the Bacteriological Code. As none were to be included in the Approved Lists of Bacterial Names, their nomenclature under the Bacteriological Code would start from names validly published in the IJSB after 1979 under Rules 27 and 28.
A draft of the Approved Lists had been published in the IJSB in 1976 [5], which initiated widespread consultations in the bacteriological community and resulted in the 1980 Approved Lists.