53 2 May 2004 485 491 Dayrat al A new species nomenclature Suggestions for a new species nomenclature Beno t Dayrat1 Christoffer Schander2 Kenneth D Angielczyk1 1 California Academy of Sciences Golden Gate Park San Francisco California 94118 U S A bdayrat calacademy org author for correspondence 2 University of Bergen Department of Biology Postbox 7800 NO 5020 Bergen Norway The PhyloCode Cantino de Queiroz 2003 which intends to replace the current international codes of nomenclature bacterial botanical and zoological or ICNBa ICBN ICZN is a rank free system in which traditional Linnaean categories such as genus family or order are abandoned It is important to note that the current version of the PhyloCode is a rank free code of nomenclature only and not a set of rules for rank free classification although we are in favor of both rank free nomenclature and classification to avoid any confusion concerning ranks Only two types of taxa exist under the PhyloCode species and clades and the terms species and clade refer to different kinds of biological entities not ranks Note 3 1 1 most recent revision December 21 2003 Because the PhyloCode governs only the naming of organisms and not classification species names should not convey information or misinformation about supra specific classification However the current binominal species nomenclature which is based on a combination of a generic name and a specific epithet by its very nature conveys information about supra specific classification Therefore it is not compatible with the independence of names and classification proposed in the PhyloCode Furthermore the use of binominal species names also is not compatible with the absence of a mandatory genus rank under the PhyloCode Cantino al 1999 These issues are especially problematic because the current draft of the PhyloCode only governs clade names it does not deal with species names We are promised p 3 that rules governing species names will be added in the future but an official schedule is not provided We assert that the PhyloCode should not be implemented if no method for naming species is proposed currently this implementation is scheduled to occur with the publication of the symposium volume based on the First International Phylogenetic Nomenclature Meeting which will be held in July 2004 Paris Otherwise we may face the paradoxical situation where the PhyloCode would oblige systematists to continue using the current rank based codes for species names There are two main classes of possible methods for naming species in the PhyloCode those that maintain a binominal form and those that are epithet based For the reasons mentioned above i e distinction between names and classification and the absence of a mandatory genus rank and thus generic names we reject the binomial based methods that have been proposed for use with the PhyloCode The potential for confusion is particularly striking in the case of the creation of new species names Therefore we argue that the solution is for species names to become epithet based A problem that must be solved in this context is how to guarantee the uniqueness of epithet based species names considering that many species share the same epithet We present an epithet based form of species name that is fully compatible with the rank free system of the Phylocode in which the genus rank does not exist Also it guarantees uniqueness in all situations However we do not intend to argue that species names under the PhyloCode must follow the method we describe although we find it convenient Instead we wish to stimulate a needed debate on the form of species names in a rank free system The absence of rules for species names in the PhyloCode A discussion of species nomenclature is conspicuous in its absence from the current draft of the PhyloCode Several issues could account for the delay in proposing a form for species names For example there is disagreement on whether or not species should be considered biological entities distinct from clades and several authors have suggested that the status of species as a special biological entity be abandoned in Phylogenetic Nomenclature e g Mishler 1999 Pleijel 1999 However the form of species names is independent of one s opinion on the distinction of species and clades and consensus must be reached on the rules for naming the least inclusive taxa regardless of whether they are species least inclusive clades or fundamental units A related debate concerns how species names should be defined e g Lee 2002 This question is of primary importance because it will determine if species names will be based on type specimens as in the current codes or by means of phylogenetic definitions similar to clades in the PhyloCode Moreover it is related to broader issues such as the applicability of phylogenetic methods at the intra specific level where 485 Dayrat al A new species nomenclature according to the Hennigian framework relationships are tokogenetic not phylogenetic Finally no method for naming species that agrees with the rank free PhyloCode has been agreed upon although several possibilities have been described Cantino al 1999 Our goal is not to discuss the conceptual issues surrounding the nature of species but rather to address the form that species names should follow in the PhyloCode This must be dealt with regardless of whether species are qualitatively different than higher clades or if phylogenetic definitions should be provided when establishing species names Furthermore a convincing form of species name is critical to impel taxonomists and users of taxon names to adopt the PhyloCode On uniqueness homonymy synonymy In the current codes uniqueness applies to all so called legitimate ICBN ICNBa or available ICZN names All of the current codes prohibit homonymy both primary and secondary and this framework guarantees that a particular combination of a genus name and species epithet is unique In the context of the current codes the uniqueness of names is a nomenclatural issue that should not be confused with the notion of correct ICBN ICNBa or valid ICZN names A valid or correct name is the name selected among all the available or legitimate names that refer to the same taxon The selection of valid or correct names is regulated by a set of nomenclatural rules such as priority but it also depends on taxonomic knowledge All available or legitimate names that are not valid or correct are synonyms Uniqueness also is one of the
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