HBW 9 - Foreword on ornithological nomenclature by Richard Banks

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Ornithological nomenclature is a branch of zoological nomenclature, and is thus “the system of scientific names applied to taxonomic units ... of extant or extinct” birds (International Commission on Zoological Nomenclature [ICZN] 1999: Art. 1.1). The words “ nomenclature” and “ taxonomy” are often used interchangeably, but if nomenclature is taken as the application and use of scientific names, taxonomy is the study of populations to determine which of them are sufficiently distinct to merit scientific names. Systematics, then, may be considered the study of the relationships between, and classification of, those named taxonomic units. It is impossible to discuss nomenclature without also discussing taxonomy, and it is nearly if not actually impossible to write more than a few sentences without using the words in different and overlapping ways. Nomenclature is the result of taxonomic decisions or actions.
 
Writing an essay on a subject that has been around as long as nomenclature is not as easy as one might think. In reviewing literature to develop ideas that I wanted to write about, I found that nearly everything I considered discussing has already been said, much better than I could possible hope to write it. For example, the development of the International Code of Zoological Nomenclature (hereafter, the Code) and of the earlier American Ornithologists’ Union [AOU] Code dedicated to avian nomenclature are well and extensively chronicled in introductions to those documents (ICZN 1961, 1985, AOU 1886). Further, Bock (1994) has given a detailed history of nomenclature, emphasizing the family-group level. Melville (1995) has traced the history of the Commission. My only hope for a semblance of originality is that many readers of this Handbook will not have ready access to, or will not have found the time to read, that historical information. Here I can hope only to summarize, and to avoid plagiarizing, those important documents. If there is anything of interest in this discussion of the development of rules for avian nomenclature, I recommend that you delve into the sources just cited.
 
 
Beginnings of Ornithological Nomenclature

There is no record of when members of some early population of mankind first agreed that a particular sound that they each made would invoke the concept of some particular kind of bird and distinguish it from other kinds of birds. It might have been to designate a scavenger that competed with them for the remains of carcasses, or the imitation of a nocturnal sound associated with a form occasionally seen flitting across the moonlit sky. When all those in the community used the same sound — a grunt, or syllable, or “word” — for the same avian concept, avian nomenclature had begun. And when members of two communities met and realized that they used different sounds for the same bird, or the same sound for different birds, problems in avian nomenclature had begun. These primitive designations eventually developed into what are now called Common or Vernacular names, of which there can be one or more sets for each human language. There are still differences, and to some extent problems, between and even within languages, despite efforts to standardize names (e.g., Eisenmann & Poor 1946, Smith 1992; see entries under “Name” in Campbell & Lack 1985).

 
Early technical nomenclature fared no better as it developed from vernacular nomenclature. Some vernacular names from Latin and Greek, in particular, became the basis for scientific names because writings by the early philosophers and scientists who used those languages have persisted. The first modern naturalists are generally perceived to have been scholars, educated in the Latin and Greek languages as a matter of course, using Latin as the primary language of science. Man’s nature is to group things, and the early writers whom we might consider the first scientists grouped objects, including kinds of birds, that seemed to share characteristics. Thus many Latin vernacular names came to be used as group names, now considered generic names. Each of the great early naturalists used meaningful group names and specified kinds within the group by a series of descriptive or geographical modifiers. Many —probably most — species of birds, as well as other organisms, received more than one such “scientific” name, usually (but not always) bestowed by different workers studying different material at different times and places.
 
Linnaeus is credited with having originated the binomial system of nomenclature used today in all phyla of biological life. In this system, the scientific name of a species of organism is composed of two parts. The first word is the name of a genus, with a capital initial letter. The second word is the species name, written entirely in lower case letters; Recommendation 28A of the Code urges authors not to use a species-group name as the first word of a sentence, in order to avoid having to capitalize the initial letter. All names at the generic rank or lower are printed in italics to set them apart from other text. Linnaeus began using generic names in botany as early as his Genera Plantarum in 1737, and some zoologists were also using generic names as early as the 1730s. He promulgated rules for binomial nomenclature in 1751 and further developed the concept with his Species Plantarum in 1753. With the 10th edition of Systema Naturae in 1758, Linnaeus consistently used binomial nomenclature for all animals, and the practice took root from that moment, though with some notable exceptions (see, e.g., Bruce, HBW 8, pp. 17-20). However, naturalists in the century after the 10th edition often coined their own binomial names for species, with little knowledge of, and perhaps regard for, names set forth by others. There were no consistent rules for uniform application of names. Of course, in today’s world of instant worldwide communication, it is often easy to forget the complications and time involved in past times in the spreading of word from one part of the world to another.
 
Origins of the Code
 
Ornithologists have had much to do with the formulation of rules embodied in the present code of nomenclature. The British Association for the Advancement of Science appointed a committee to develop some rules to regulate zoological nomenclature. The committee included Charles Darwin, among other notables of the day. Ornithologist (and geologist) Hugh E. Strickland was the “ reporter” for the committee, probably the secretary in modern terminology, and probably the primary author of the resulting “Series of Propositions for Rendering the Nomenclature of Zoology Uniform and Permanent.” This report was adopted by the British Association in 1842. It was soon adopted also by the American Association for the Advancement of Science and by similar bodies in other nations. Modified in various ways through the decades, the Stricklandian Code, as it became known, was followed “with more or less reservation and evasion by naturalists at large” into the 1880s (AOU 1886: 4).
 
When the American Ornithologists’ Union was founded in 1883, one of the first committees established was that on Classification and Nomenclature. At that time, American ornithologists had their choice of at least four differing lists of American birds, by Spencer Baird from 1858, Robert Ridgway in 1880, and Elliot Coues in 1873 and 1882. The task of the committee (which included both Coues and Ridgway) was to amalgamate these lists into one that would be acceptable to all North American workers. The committee found it necessary first to examine the principles of zoological nomenclature, and the rules and practices of avian nomenclature in particular. This led to the formation of a “Code of Rules” for the guidance of the committee in fixing the name of every North American bird. The “Principles, Canons, and Recommendations” that formed the AOU Code of Nomenclature were published as a preamble to the first Check-list of North American Birds in 1886. Because this code was the first dedicated particularly to avian (rather than all zoological) nomenclature, and because it had an influence on the development of the present International Code of Zoological Nomenclature, we may examine it in some detail.
 
The AOU Committee took the Stricklandian Code as its point of departure, intending “ to reaffirm and reproduce as many of its rules as may be desirable ... and then to build upon such a foundation with those additional recommendations and suggestions which in the judgment of the Committee are required to meet the demands of the present state of zoological science, and which seem most timely in view if its evident tendency, and probable progress in the future.” The main departures from the earlier Stricklandian Code were (1) the adoption of the date of the 10th edition of the Systema Naturae, 1758, instead of that of the 12th, 1766, as the starting point for the law of priority and therefore official nomenclature; (2) the rule that prior use of a name in botany does not make that name unavailable in zoology; and (3) adoption of the principle of trinomial nomenclature, providing for the nomenclatural recognition of subspecies. These departures are discussed in some detail below.
 
Linnaeus (and others) had used binomial nomenclature to some extent in earlier works, but it was not until the 10th edition of Systema Naturae in 1758 that the system of a distinctive generic and specific name for each species was used consistently in a single work. In the 12th edition, in 1766, many more species were included and names of some of the species in the 10th were changed. It is said that in the original draft of the Stricklandian Code, the number of the edition of Systema Naturae designated as the start of the law of priority, and thus binomial nomenclature, was left blank, and “twelfth” or “XIIth” was filled in by the committee approving the report. Even though it was recognized that binomial nomenclature had begun in earnest with the 10th edition, the 12th was maintained in the rules for many years because changing to the earlier date would require many changes of names and cause much confusion. The AOU committee, however, disagreed with that reasoning and selected the 10th edition. Its reasons were: (1) “the Xth edition is the one in which Linnaeus first introduced the binomial nomenclature, and in which its use is uniform, consistent, and complete;” (2) “This date [1758] admits to recognition the works of Artedi, Scopoli, Clerck, Pallas, Brünnich, Brisson . . . ”, who had published important binomial taxonomic works between the 10th and 12th editions of Linnaeus and whose names used by Linnaeus in the 12th would thus be attributed to him rather than to their true authors; (3) the 10th rather than the 12th was in fact accepted as the starting point by a majority of naturalists in North America and Europe; (4) using the date 1758 resolved many questions of synonymy or homonymy which arose because Linnaeus changed in the 12th edition some names he had used in the 10th (Sherborn 1899); (5) the context of the draft of the Stricklandian Code implied that the 10th edition was intended to be the starting point, but that the 12th was inserted arbitrarily when the edition number was left blank; and (6) adoption of the 10th edition required very few changes in nomenclature then in use in most fields of zoology. Recognition of the 10th edition as the starting point was accepted universally when the present International Code was formalized.
 
The Stricklandian Code related only to zoology, and was silent on any relationship with botanical nomenclature. The restriction to zoological nomenclature was affirmed in various committee decisions in following decades. The AOU Code also related only to zoology, and indeed specified that there was “no necessary connection” between the two nomenclatural systems, and that use of a name in botany did not preclude its use in zoology, or vice versa. This was accompanied, however, by a strong recommendation that zoologists avoid using names already in use in botany.
 
The AOU Code did not introduce the concept of the subspecies, but it was the “first formally to enunciate the principles of the new method” of trinomial nomenclature for those forms that are known to intergrade in physical characters. The trinomial system was not a replacement for, but an extension of, the binomial system, which was to continue in use for those forms that are not known to intergrade. Trinomial nomenclature consisted of dealing with an organism of a population known to intergrade with another by applying to it three names, “one of which expresses the subspecific distinctness of the organism from all other organisms, and the other two of which express respectively its specific indistinctness from or generic identity with, certain other organisms; the first of these names being the subspecific, the second the specific, and the third the generic designation ...” Adding a third part to the binomial name “amplifies, increases the effective force of, and lends a new precision to, the old system.” Most of us today would do well to reflect that the generic name indicates “identity” in certain distinctive characters with other species, the species name indicates “indistinctness” from populations that intergrade or vary clinally, and the subspecific name indicates “distinctness” of a population in morphological characters because of geographic and environmental conditions (AOU 1886: 16, 30-31). This might also be taken as an early formulation of the biological species concept. The third name used was, under the AOU Code, to be formed in the same way as, and subject to the same rules as, the specific name, as is the practice today when the two names are treated together as “species-group” names in the International Code of Zoological Nomenclature. The latter Code recognizes that the use of a name at the species or subspecies level reflects a taxonomic decision, and does not consider the use of a trinomial as a deviation from binomial nomenclature.
 
One may see other forms of a scientific name that appear to differ from the binomial form. The name of a subgenus (with a capital initial letter) may be interpolated, in parentheses, between the generic and specific names; it is not counted as part of the binomen (Code, Article 6). Amadon (1966, 1968) introduced the concept of a superspecies, consisting of closely related but geographically separate allospecies. The name of the superspecies (the senior of the allospecies names) would be placed in square brackets before the name of the species. This system has been adopted by Sibley and Monroe (1990), among others. Similarly, Amadon and Short (1976) advocated the designation of megasubspecies, to be indicated (where used) by a species-group name interpolated in parentheses before a species name, to set apart a group of subspecies sometimes or potentially recognized as the species level. This burden on the concept of a binomial name has not come into general use, although it survives in the “group” names used by Sibley and Monroe (1990) and the AOU (1983, 1998). These interpolated names, when used, relate to classification rather than nomenclature, and are not counted as part of the binomial or trinomial name.
 
In addition to the Stricklandian and AOU Codes, national codes were adopted in France and Germany in the late nineteenth century. With the convening of the first International Congress of Zoology in 1889, a set of rules was proposed, but not adopted, for international use. A set of French rules was adopted at the second Congress (1892), and at the third Congress (1895) an international commission was appointed to study all existing rules and to develop a truly international code (see Melville 1995). At the fifth Congress in 1901, parts of that commission’s report were accepted, and that action is regarded as the adoption of a code, published in 1905 as the Règles internationales de la Nomenclature zoologique in French, with English and German translations. The Règles have been modified and amended throughout the century, but in essence they are still in effect today as the International Code of Zoological Nomenclature, now in its fourth edition. The full history of the present Code has been set forth in greater detail in the prefaces and introductions to the various editions of the Code (ICZN 1961, 1985, 1999) and by Bock (1994). The Commission continued under the auspices of the International Congresses of Zoology until they ceased in 1972, when authority for it was transferred to the International Union of Biological Sciences (Melville 1995).
 
The International Trust for Zoological Nomenclature was established in 1947 to handle the finances of the Commission. The Trust is a registered charity under United Kingdom law and thus is free of taxes on income, including that from sales of publications such as the Code (Melville 1995). The Trust still is largely dependent on contributions. It exists to manage funds in support of the Commission, and serves as its publishing arm. It publishes the quarterly Bulletin of Zoological Nomenclature and the Official Lists and Indexes of Names in Zoology as well as the Code. At the time of writing, the Trust has announced a plan to raise a significant endowment to ensure its continued ability to support the work of the Commission.
 
Applying the Code: Rules and Categories
 
The Code is based on several principles, some of which follow almost precisely those listed by the AOU in 1886. The Code does not infringe on an individual’s taxonomic judgement. Nomenclature does not determine the rank given to any assemblage of animals, but rather, through the process of typification, provides the name to be used for a taxon at whatever limits or rank are given to it. Every name covered by the Code is permanently attached to a name-bearing type. For species and subspecies, the type is a single specimen (preferably) or a particular set of specimens. For genera and subgenera the type is a species, and for families the type is a genus. The Code does not apply to groupings above the family level. The Principle of Priority determines (with some exceptions) what name is valid in any rank in which a population or assemblage is assigned by the individual taxonomist or systematist. Such an assemblage can have only one valid name, and the same name cannot be used for more than one taxon.
 
The goal of the Code is to promote stability in nomenclature; the primary way this is accomplished is by the Principle of Priority. The first name properly applied to a taxon remains the correct name for that taxon. The beginning date for purposes of priority is 1 January 1758, deemed to be the date of publication of the tenth edition of Linnaeus’s Systema Naturae. For this reason, Linnaeus is credited with naming more currently recognized (by Sibley and Monroe 1990) species of birds than anyone else — about 710 (A. P. Peterson, pers. comm.). To be “available”, a name must be properly formed and published in accord with criteria set forth in the Code (Art. 10). New names proposed after 1999 must be explicitly indicated as being new (Art. 16). This new provision is intended to prevent the accidental naming of a form, as has happened in the past at times when a name and sufficient diagnostic information has been published in a newspaper or other news item about a discovery of a new species.
 
Names at the family-, genus-, and species-group level are based on types. Family-group names are composed of the stem (or root) of the name of the type genus with a suffix appropriate to the level of the name— -oidea for a superfamily, -idae for a family, -inae for a subfamily, -ini for a tribe, and -ina for a subtribe (Art. 29.2). A family-group name can be used at any, or all, of these levels, but not all levels need to be used in any classification. If two or more genera, each being the type genus of a family name, are combined into a single family, the earliest name at the family-group level has priority and cannot be replaced by a later-proposed family-group name. Bock (1994) has provided a detailed analysis of family-group names in birds, including a few exceptions to the law of priority at that level.
 
The type of a genus (or subgenus) is a species, but the name of the genus is not based on the name of the type species. In most of the recently named genera, the type species was designated when the genus was named. In many early works (e.g. Linnaeus), generic names were used without a type species being indicated, as the concept of types for genera was not introduced until the Stricklandian Code appeared. If a genus was established for a single species, that species is the type by monotypy. To be sure of stability of generic names, type species for other genera were established by subsequent designation, many of those in birds being proposed by G. R. Gray (1840, 1855). In instances where the name of an included species was used also in a generic sense (often by Brisson), that species became the type species by tautonomy. This becomes rather more complicated in the case of “Linnaean tautonymy”: when a new genus is first introduced, if one of the species originally included in it has as one of its listed synonyms a pre-1758 single-word name that is identical to the name of the new genus, it becomes the type species. For example, among the eleven species in Linnaeus’s (1758) genus Strix was one he named stridula. His reference base for that species was a pre-binomial, seventeenth-century use of the name “Strix” by Aldrovandus, where the single word was used to denote a particular species. Thus, stridula is the type species of Strix by tautonomy, although it is now considered to be a synonym of Strix aluco. If two authors name genera with the same type species, the later-named genus is a junior objective synonym. If two authors name genera with different type species that are later considered to be congeneric, the later name is a junior subjective synonym of the first that might be used at a subgeneric level or again at the generic level if the two species are again determined to be distinct at that level. Thus, the level of a genus-group name depends on the individual ornithologist’s classification of the type species. Although a few species of birds distinctive enough to warrant separate generic status may yet be discovered, and new genera might be erected for species already known but in the future considered to warrant generic separation, for instance on biochemical grounds, it is reasonably safe to say that generic names in birds are now well established, although the number to be recognized will continue to fluctuate as the relationships of species are re-evaluated. Charles Sibley once told me that there are more names of genera available for hummingbirds than there are species in that family.
 
The type of a species-group name is an individual bird (holotype) or a series of individuals (syntypes). For species-group names proposed after 1999, a holotype or a series of syntypes must be designated and, if preserved specimens, the name of the collection where the specimens are or will be deposited must be given (Article 16). As the name-bearing specimen, the type defines the species (or subspecies). Non-taxonomists may tend to think that the type specimen is a “typical” member of the species, but no individual can really be typical in all respects. A species is composed of individuals of both sexes and of several age groups that represent the entire range of variation in the species in size, proportions, color, vocalizations, and behavior. No holotype can demonstrate all this variation; it is doubtful that a type series can do so. Still, a type specimen should be easily recognizable as a member of the species for which the name stands.
 
If a name is based on a series of specimens, with no one designated as the holotype (Articles 72, 73), all members of the series are syntypes. If one individual is designated as holotype, the others in the series are paratypes. It sometimes happens that a type series is composed of members of more than one species or subspecies. If an individual has been designated as a holotype, that specimen is the standard of the name. If there is no holotype and the identity of the taxon is in doubt, one of the syntypes may be designated a lectotype; it serves the name-bearing function of the holotype. The other syntypes then become paralectotypes. If no name-bearing type or member of the original type series is believed to be extant, and it is necessary to fix the identity of a taxon, a neotype may be designated. Designation of a lectotype or neotype is seldom necessary in ornithology, and these actions are strictly regulated by the Code (Articles 74, 75).
 
The type locality of a species is the locality from which the name-bearing specimen(s) originated. If no holotype has been designated, the type locality encompasses the localities of all syntypes. Under certain circumstances, a stated type locality may be modified (restricted) or corrected. For example, many South American birds have Bogotá [Colombia] as the originally designated type locality, but Bogotá was the place from which specimens taken in a large surrounding area were shipped to Europe, not necessarily the precise origin of the specimens (Chapman 1917). If the type locality of a species is general or vague, a student of geographic variation who wishes to name additional subspecies of the species must attempt to make the original type locality more specific or restricted. Linnaeus (1758) based the name of the American Blue Jay, now Cyanocitta cristata, on a painting by Mark Catesby, giving the locality only as “America septentrionali,” or northern America. That locality was restricted to “Carolina” (AOU 1910) and further restricted to “southeastern South Carolina” by Oberholser (1921) when he named the more northern birds Cyanocitta c. bromia.
 
Historically, many species of birds were first named on the basis of illustrations. Linnaeus (1758) named many species on the basis of paintings by Catesby, Edwards, and others. Although the painting (or other illustration) is often spoken of as the type, the actual type is the bird that was illustrated. The identity of the population from which the illustrated bird originated is in most cases known or at least accepted by now, but nomenclatural problems can arise if concepts of geographic variation change. The name of the Black-bellied Whistling-duck, Dendrocygna autumnalis, was based by Linnaeus (1758) on a plate and description by Edwards (1751) from the West Indies, possibly Jamaica. Most authors considered the illustrated bird to be representative of the populations in Central and North America, and a second species, Dendrocygna discolor, later considered a subspecies of D. autumnalis, was described from South America by Sclater and Salvin (1873). Subsequent re-examination of patterns of variation and of distribution led to the realization that Edwards had actually illustrated a bird of the South American form, hitherto known as discolor, that had been translocated to Jamaica. As a result, the first species-group name, autumnalis, replaced the name discolor for South American birds, and a much later name, fulgens, had then to be applied to the Central and North American birds (Banks 1978; compare treatments of the species by Peters (1931: 153) and Johnsgard in Mayr and Cottrell 1979: 430).
 
A tendency has developed in recent decades to name species or subspecies of birds without a preserved specimen, basing the name instead on living birds or on photographs (e.g., Welch and Welch 1988). The negative aspects of that practice were discussed by Vuilleumier and Mayr (1987) and by Banks et al. (1993, for many others), and recommendations were proposed to avoid future such occurrences. The most recent Code (ICZN 1999) states (Art. 72.10) that “Holotypes, syntypes, lectotypes, and neotypes are the bearers of the scientific names of all nominal species-group taxa (and indirectly of all animal taxa). They are the international standards of reference that provide objectivity in zoological nomenclature and must be cared for as such ... They are to be held in trust for science by the person responsible for their safe keeping.” A wild bird that is photographed can be the “type” of a name — but it can fly or even walk away, never to be seen again. In that instance, there is no person responsible for its safe keeping. The person who houses the photograph cannot be responsible for the individual that was the subject of the photograph. The person who established the name based on an itinerant individual bird cannot logistically or reasonably assume responsibility for the safe keeping — whatever that concept may entail — of a wild bird. One might conclude that it is irresponsible to designate a type that cannot possibly be provided any degree of safe keeping by anyone. If a wild bird that is temporarily restrained for the purpose of photography becomes the type of a name based on a photograph, it is not responsible safe keeping of the “specimen” to release it into the wild. Payne (1989) has discussed an instance of a name based on photographs.
 
When a name is based on a photograph, the type is the individual photographed; after a period of time, the type is “lost.” Therefore it would be permissible to designate a specimen with those characteristics as a neotype under the appropriate condition, when “an author considers that a name-bearing type is necessary to define the nominal taxon objectively” (Article 75.1). Thus, if a species is revised and the status of a name or of a taxon based on a photograph is in doubt, the reviewer can designate a neotype. If this is done, the photograph on which the name was based loses its value. Thus, any photograph of a bird is liable to become worthless from a nomenclatural standpoint. Perhaps one of the strongest arguments against the use of photographs in this way comes from recent advances in the form of digital photography, which would make it all too easy for the unscrupulous to “invent” a species simply by manipulating photographs on a computer.
 
Applying the Code: Naming Birds
 
Most genera and species of birds have already been described and named; indeed, many have been named several times. Mayr (1957) suggested that probably no more than 20 species would be named in the next decade. Even though he later (Mayr 1971) realized that the number of new species was “by no means nearly exhausted,” and new species are being found until this day, the primary taxonomy of birds (except fossils) must be nearing an end. Most work in avian nomenclature in the future will not involve the coining of new names, but rather will concern the proper treatment of names of populations whose taxonomic status is changed because of new evidence about their relationships. Much of this will involve the elevation of what are now considered subspecies to the species level, the moving of a species from one genus to another, or moving a genus (with most or all of its included species) from one family to another. Each of these actions has been taken recently (Banks et al. 2003) to reflect new information provided by studies of genetics. The name of the population moves with it, but taxonomic changes may necessitate nomenclatural modifications. If a species is moved from one genus to another, the spelling of the species name, or that of a subspecies, may have to be changed slightly to reflect agreement in gender with the name of the newly assigned genus. For example, if the Snowy Owl, long known as Nyctea scandiaca, is transferred to the genus Bubo, as recommended by Wink and Heidrich (1999), the name becomes Bubo scandiacus. There is a possibility that the species (or subspecies) name might already be (or have been) in use in the newly assigned genus, in which case an older name may have to be resurrected or a new name may have to be coined. When the Fork-tailed Flycatcher, known as Muscivora tyrannus (Linnaeus, 1766), was moved into the kingbird genus Tyrannus by Smith (1966), the combination Tyrannus tyrannus (Linnaeus, 1766) was preoccupied by Tyrannus tyrannus (Linnaeus, 1758) and the flycatcher became known as Tyrannus savana Vieillot, 1808, using the next available specific name.
 
On the assumption that few new species names will be coined, it seems unnecessary to write a great deal about how that should be done. LeCroy and Vuilleumier (1992) have published guidelines for that procedure that should be consulted by every­one contemplating naming a new species. Helbig et al. (2002) give suggestions for the determination of the rank at which a new (or old) form might be recognized. The Code (ICZN 1999) sets forth the rules of nomenclature in sometimes excruciating detail. An ornithologist who spends much of his professional time on taxonomic and nomenclatural matters should become (if not already) conversant with the Code. Those ornithologists who find it necessary as a result of their studies to propose a nomen­clatural change should become familiar with the Code or form an alliance with one who is knowledgeable, or both. Editors of journals that publish papers about birds should be alert to changes in nomenclature that may form a part of newly submitted manuscripts, and should refer such papers to a colleague who is trained and competent in nomenclatural matters.
 
Perhaps the hardest to reach with an admonition is the worker who is barely aware that a code of nomenclature exists, and who in excitement at finding something new inadvertently publishes enough information about his or her find in a non-typical publication outlet (such as a newspaper), thereby almost or actually constituting a naming of a taxon. Article 16 of the current Code (fourth edition, 1999) sets forth very explicit requirements for new names published after 1999, which should avoid accidental namings. It is best if a scientific name is not mentioned before the intentional formal description of a new taxon. It might find its way into print, where, even if not accidentally validated, it will be a nomen nudum, a new name unaccompanied by a description or definition (Article 13). For example, when a population of Sage-grouse was discovered in Colorado, USA, that was notably smaller than typical Sage-grouse (Centrocercus urophasianus), a decision was made to refer to it by the name minimus. The combination Centrocercus minimus was used at least twice in papers about the biology of the population (e.g. Commons et al. 1997) and once as a passing reference to identify a picture of the bird before the name was formally proposed as a new species (see Banks et al. 2002: 899). However, a nomen nudum is not available and has no standing in nomenclature, and thus can be used later for the same concept (Code, Glossary), as in this case by Young et al. (2000), when the new Sage-grouse was formally named.
 
A name that is found to be based on a hybrid is not valid and cannot be used for any taxon, even one of the parental species (Articles 17.2, 23.8). Such a name remains available, however, and can be a homonym (see below). Rasmussen and Collar (1999) determined that the name of the supposedly endangered parrot species Psittacula intermedia (Rothschild, 1895) was used for birds of hybrid origin. This is not a valid species, and the name intermedia cannot be used again in combination with that generic name (or the former generic name Palaeornis, in which it was originally described, should that name be revived). What might seem contradictory is that the “availability” of the specific name in this instance means that it cannot again be used in combination with either generic name; those combinations are “taken” and cannot be used for a different entity. The second use of the combination would create homonymy, use of the same name for two different taxa. This contrasts with the Sage-grouse example in the paragraph above.
 
A few basic rules must be mentioned, to aid in the naming of new species and generic transfers. A genus-group name is, or is treated as, a Latin noun in the nominative singular (Art. 11.8). A Latin noun connotes a gender (masculine, feminine, or neuter), and the gender of a genus-group name is determined by provisions set out in Article 30. Recently, David and Gosselin (2002b) have reviewed currently used generic names of birds and have determined or verified their gender by strict interpretation of those provisions. For any generic names proposed in the future, the derivation and gender should be specified. If new information on relationships necessitates the splitting of a genus and the revival of an old generic name, the gender of that name will need to be evaluated carefully.
The name of a species, or subspecies, must be (or have been) published in combination with a generic name and must be an adjective or participle in the nominative singular, a noun in the nominative singular standing in apposition to the generic name, a noun in the genitive case, or in some instances an adjective in the genitive case (Art. 11.9). A species-group name that is a Latin or Latinized adjective, or a participle in the nominative singular, must agree in gender with the generic name with which it is combined, and if transferred to a genus of a different gender must be changed to agree with the newly combined genus, as mentioned above. A species-group name that is a noun in apposition is invariable and does not necessarily agree in gender with the generic name. A name that is not Latin or Latinized does not change and need not agree in gender with the generic name. As with genera, rules for determining the nature of species-group names are detailed in the Code (Art. 31). Even so, some of the rules are difficult to apply properly, especially if one does not have a working knowledge of classical languages. David and Gosselin (2000, 2002a) have reviewed most current species-level names and have determined which should be considered invariable.
If the same name is applied to more than one entity at the same taxonomic level, the names are homonyms. The name proposed later, or junior homonym, is said to be “preoccupied” and must be replaced by another name. If one must coin a name for a new genus, therefore, one must be certain that it has not been used previously — not only in ornithology but in any animal group. In naming a species or subspecies, one must be certain that the name has never been used in the genus. It is best if the name has not been used in a closely related genus, to reduce the risk of creating secondary homonymy if the genera are later merged.
 
To avoid the inadvertent use of a generic name that has already been used, one may consult the official list of names that have been ruled on by the International Commission on Zoological Nomenclature (ICZN 1987, 2001). Avoiding homonyms at the species-group level is possible by being familiar with the names in use in the genus, as a specialist should be, or by consulting synonymies in such works as the Catalogue of Birds in the British Museum or Ridgway’s Birds of North and Middle America, as far as it goes. One must avoid not only names that are currently accepted as valid for a taxon, but any name that is available even if presently considered a synonym of a current name. John Penhallurick of Australia is working on a bird data project (http://worldbirdinfo.net/ ) that will eventually list all combinations of generic and specific names of birds that have been used. When completed, this will be an extremely valuable tool, among other things for avoiding the creation of homonyms.
 
There are a few situations in birds where more than one spelling of a name is, or might be, in use. Browning (1989) showed that Swainson’s generic name generally rendered as Ptilogonys was originally spelled Ptiliogonys. However, Swainson himself in various writings used both spellings, and the original form has not been used since 1887. Sibley and Monroe (1990) suggested that Ptiliogonys should be considered an incorrect original spelling and Ptilogonys a justified emendation, a course of action followed by the American Ornithologists’ Union (1998). Under the present fourth edition of the Code (1999), the concept of “ prevailing usage” (Art. 23.9.1) allows Ptilogonys to be considered valid because the original spelling has not been used after 1899 (Browning 1989) and the present spelling has been used consistently.
 
In my view, the concept of prevailing usage is, in addition to being contrary to the principle of priority, difficult to apply in ornithology. The concept is defined (ICZN 1999, Glossary) as “ that usage [including spelling] of the name which is adopted by at least a substantial majority of the most recent authors concerned with the relevant taxon, irrespective of how long ago their work was published.” Explicit rules are set forth in Article 23.9. In many fields of zoology, names are mentioned only infrequently in the literature and then only by specialists who consciously decide at the time of writing which spelling to use. Even in those fields, it may be difficult to know where all uses of a name occur and to determine which of two alternatives was used by a majority of authors. In ornithology, names may be used in dozens or hundreds of non-taxonomic papers, field guides, and faunal lists by non-specialists who may use a particular spelling merely because it was used in some other recent paper, with no conscious consideration of articles of the Code and presumably with little nomenclatural “concern” for the particular taxon.
 
A new name should be proposed only when the author is certain that the population to be named is distinct from all other avian populations at the level at which it is named. Names based on minor variants or on samples that are too small to show distinction convincingly are probably destined for synonymies, and in essence do nothing but clutter the literature. In the past, it was possible to name a population that the author believed might prove to be distinct, as Baird (1859) did with Myiarchus pertinax of Baja California, Mexico. Such “conditional” names are not valid if proposed after 1960 (Code, Article 15).
 
Although it may be presumed that ornithologists believe that species they describe and name as new actually are “new” and distinct at the species level, the record shows that many are mistaken. In 1934, Meise (1938a) provided an analysis of 600 new species named from 1920 to 1934. He considered (Table 1) that only about 25% of the names proposed in that time were valid at the species level. Periodically since that time, new species names have been evaluated, by Meise (1938b) and by ornithologists at the American Museum of Natural History, New York (see Table 1 for references). From 1920 to 1990, more than 900 new species names were proposed, of which only about 30% were considered to be valid at the species level when analysed. The rates for valid species for any period may be slightly different because of differing taxonomic concepts. Some taxa recognized as valid species originally might now be considered only subspecifically distinct, or vice versa.
 
The number of species described per year declined greatly after 1941 (Table 1), perhaps a response to greatly reduced collecting during and after World War II, but remained relatively stable in the last part of the century. The proportion of species that were generally deemed valid soon after their descriptions increased in that period, and is now probably something in the order of 60-65%. Similarly, the annual number of newly described species that were considered valid by initial reviewers has held rather steady in the last half century, at about 3 per year. Most of the rest of the new names are considered synonyms of names already in use, while some are reckoned valid at the subspecies level. A few are invalid names, based on hybrids or otherwise not in compliance with the Code.
 
Norbert Bahr (pers. comm., June 5, 2003) has compiled a list of new taxa of birds described since 1970. Among the nearly 1300 taxa validly described are 170 named as new at the species level by 2000. In that 30 year period, the rate of naming of new species was 5.7 per year. The proportion of those described that are generally considered distinct at the species level has not been evaluated, but if it is the same as for 1981-1990 it would yield about 3 species per year.
 Bahr’s figures suggest that about 1100 birds were newly described at the subspecific level in 1970-2000, a rate of about 37 per year. To my knowledge, there has been no independent evaluation of the validity of most of those names, and opinions are likely to vary widely.
 
What’s in a name?
 
What should be the source of a name for a bird population? This is entirely at the discretion of the namer. The Code is silent on the source of the name, but it should not have been used previously in the same (or a closely related) genus. Frequently used, now as in the past, are names to honor people, names based on geography, and words that are suggestive of the bird or its characteristics (behavior, ecology, voice). Less frequently used are terms that indicate supposed relationships or similarities to other birds. The third edition of the Code (1985) gives recommendations (Appendix D) for the formation of specific names in most of these categories, unfortunately not reprinted in the fourth edition. Recommendations in the Code do not have the force of rules, but life is easier for all of us if they are followed. The Code (Article 31, 1999) does give specific rules for the formation of species-group names formed from personal names, or patronyms.
Alan Peterson (pers. comm.) has provided a list of species names used in currently recognized bird species, in order of frequency. The top 30 names, including those used 16 or more times, appear in Table 2. This list suggests the features of birds that are most important in their recognition or definition. These are size, color, features of the head, including the bill, and geographic origin.
 
The name minor is the most frequently used descriptor of size, occurring 26 times. At the other end of the scale, major is used for 15 species. If maximus and minimus (for adjectives that have variable endings to indicate gender, I give only the masculine in this section, to include also feminine and neuter endings) are taken into account, small birds slightly outnumber large ones, but there are many other words used to indicate size or relative size.
 
People who have named birds have been impressed by the variety, or lack of variety, of color on their subjects. The number and variety of colors has been important — unicolor and bicolor each appear 21 times, tricolor 16 times, and quadricolor and quinticolor each twice. The name concolor (9 times) presumably is the same as unicolor, suggesting that relatively drab birds outnumber multicolored ones, until versicolor (16), discolor (= variegated) (5 times) and multicolor (4) are considered.
 
The basic colors of birds are also reflected by their names. The most frequently used color descriptor is cinereus (40), followed by olivaceus (30), niger (27), fuscus (26), and viridis (25). I have not attempted to determine how frequently these colors occur in compound words.
 
Except for a notation of a crest (cristatus, 30) crown (coronatus, 22), or tail (caudatus, 11) the names of body parts generally do not appear without modifiers. Features of the head seem to be the most remarkable. Roots indicating head characteristics such as - ceps (135), - cephal- (116), and - capill- (71), often combined with color-indicating prefixes, are most frequent. The nature of the bill, - rostr- (182), in size, shape, or color, is often noted. The presence of a collar (collaris 103, torquatus 49) is also a frequently noted distinguishing character, alone or with a modifier.
 
Many species are known for where they occur or were first found. Senegal is the locality most frequently noted in a specific epithet, with 18 names in some form, mostly senegalensis. Six of the 13 species with the epithet senegalensis were named by Linnaeus (1766) in the 12th edition of Systema Naturae, suggesting that he had a fixation on that locality. However, all are based on the same names used by Brisson, whose pre-1766 work was not consistently binomial, denying him modern credit for names proposed in them. A similar situation holds for the frequently used (16 times) name madagascariensis, with variants. Linnaeus named 5 of 14 species with that epithet in 1766, and Gmelin added two in 1789, all using a name previously used by Brisson. Other place names with multiple uses are americanus (16), mexicanus (16), and nipalensis (16).
 
The individual most honored by having bird species named after him is P. L. Sclater, whose name is the basis of the current valid species name for 18 species (Table 3). The index volume for the Peters check-list (Paynter 1987) lists 74 species level entries based on Sclater’s name, although a very small number of these may perhaps honour his son, W. L. Sclater. Some of the other 56 entries represent synonyms of presently accepted species names as combined with other generic names, whereas others are presently recognized at the subspecific level. A quick review of that index volume suggests that John Gould, with more than 40 entries, should be among the most recognized in avian nomenclature, but there are actually only three currently valid uses of his name as a species name. Perhaps somewhat ironically, neither Linnaeus nor Gmelin, compilers of the Systema Naturae, has a bird species validly named in his honor.
 
From the data base on his web site (www.zoonomen.net), Alan Peterson has tabulated the names of authors credited with establishing the largest numbers of names of currently recognized (Sibley and Monroe 1990, updated) bird species (Table 4). As the author of the first work to be considered for the law of priority, Linnaeus understandably takes top place, being credited with about 710 current species names. Not all of the 710 date from the 10th edition of the Systema Naturae, however. Some are from the 12th edition and a few are from other works. Even so, this is less than 10% of the approximately 10,000 species now recognized. Statius Muller (1776), in a supplement to a German edition of Linnaeus, and J. F. Gmelin (1788/89), primarily in a 13th (= 14th, see Iredale 1958) edition of Systema Naturae, added 433 species, so it can be said that Linnaeus’s work and expansions on it account for about 1143 names. A few other authors actively provided names for birds in the period between the 10th and 12th editions — Scopoli, Brisson, Pallas, and Brünnich, for example — and a few others, such as Latham, before the turn of the nineteenth century. Perhaps as many as 1400 species had been named by that time. There was then a quiet time in naming new bird species that lasted from shortly after Gmelin’s 13th edition until about the 1820s, when Vieillot began to name a large number of taxa. Publication of large numbers of names continued until about 1900. There was some slackening until about the 1940s and World War II, after which the number of new names has been moderate and fairly regular.
 
Conclusion
 
This essay has covered only a few of the 90 articles of the International Code of Zoological Nomenclature. The Code is a complex document that still requires interpretation and refinement. It is not important that every ornithologist or birder who finds, or thinks he finds, a new taxon be an authority on the Code, but everyone who wants to name a new species or subspecies should be aware that there is a Code, and be willing to seek assistance in complying with it. Editors, in particular, should be alert to possible taxonomic implications in papers that they receive for publication, and be certain that at least one referee or reviewer is familiar with this aspect of our science. In the not-too-distant past there have been instances of birds being named, or almost named, by accident or in a non-scientific publication. Certain provisions of the current Code are designed to decrease the likelihood of that happening by requiring an explicit statement that a taxon is new, and that a type be designated and the place of its deposit be indicated. With just a little co-operation and forethought we can be assured that ornithological nomenclature will retain the high standards it is known for.
 
 
Richard C. Banks
National Museum of Natural History
Washington DC
USA
 
 
 
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