Taxonomy

Introduction

The naming of organisms – nomenclature – is governed by International Committees which provide rules such as the International Code of Nomenclatural for algae, fungi and plants (ICN), the International Code of Zoological Nomenclature (ICZN), the International Code of Nomenclature of Prokaryotes (ICNP), the International Code of Virus Classification and Nomenclature (ICVCN), the International Code of Nomenclature for Cultivated Plants (ICNCP), the International Code of Phylogenetic Nomenclature (PhyloCode). The categorizing of organisms into groups – taxonomy – has no formal rules but is considered to be integral to scientific freedom ensuring the application of current concepts to increasingly significant data. Nevertheless, a certain amount of governance of taxonomic lists seems to be needed for international cooperation such as the Convention on Biological Diversity (CBD) because competing classifications can cause confusion among users of scientific taxonomic names. In this session, members of the International Committee on Bionomenclature (ICB) which encompasses the BioCode and the above special codes on nomenclature, want to provide their experience with governance and set the baseline for further discussions with the members of the group initiating governance of taxonomic lists.

1. Frank Zachos (Natural History Museum Vienna, AT): The incommensurability of the species category and the need for standardised taxonomic lists

Taxonomy is arguably the most fundamental biological discipline as everything "downstream" of it depends on some kind of classification. It is time that taxonomy was also appreciated as such by other biological disciplines. However, it suffers from an inherent limitation, namely that it entails the imposing of an essentially discrete system (species or no species) on a fundamentally continuous process (evolution). This is neither taxonomy's fault nor can it be fixed objectively. It must be accepted and dealt with, which means that there will always be a grey area in which assignment of individual organisms to one species is equally defendable as assignment to two (or even more) species. In this grey area, taxonomic decisions are still based on scientific and testable data but also include an executive decision as to which way classification should go (lumping or splitting). As a consequence, the species category (not the species taxon) includes some unavoidable level of arbitrariness, introducing an apple-and-oranges problem into all analyses that use the species category as the currency in comparative and conservation biology. I will briefly explicate this incommensurability problem and argue that where complete objectivity cannot be reached, consistency should be the aim, and importantly this means that taxonomic lists need to be standardised as far as possible, which is where the follow-up talk by Stijn Conix will take over.

2. Stijn Conix (Centre for Logic and Philosophy of Science, KU Leuven, BE): Basic principles for an authoritative global list of species

Building on Frank Zachos’ talk on the incommensurability problem of species classifications, I will make a case for an authoritative global list of species as an attractive solution to this problem. To do this, I will first briefly elaborate on how the lack of such a list causes problems for end-users of taxonomy. I then propose six basic principles that should guide the construction of an authoritative global list of species, and point to crucial questions that need to be addressed when constructing such a list. Finally, I address two important objections one might raise against an authoritative species list: first, that it poses a threat to the autonomy of taxonomy; and second, that it adds a superfluous bureaucratic burden to a discipline already lacking funds and manpower.

3. Wolf-Henning Kusber (Botanic Garden and Botanical Museum, Freie Universität Berlin, DE): Does algal nomenclature provide what taxonomic governance needs?

The name registration of algal names available at www.phycobank.org is in line with the provisions of the International Code of Nomenclature for algae, fungi, and plants (ICN). PhycoBank has been set up to serve the taxonomic community. This nomenclature based information system can feed names backbones but will and should be taxonomical neutral. However, it administers nomenclatural as well as taxonomic information which is needed for any taxonomic work respectively taxonomic governance. Examples from micro algae are here chosen because of the taxonomic challenges in a group of organisms invisible without a microscope, as compared to higher plants, birds or mammals. Experiences with names and taxa of the Red Lists for major indicator groups reveal difficulties as well as pitfalls in comparing European Lists. Analyses of taxonomic concepts may help to compile regional, national and international data.

4. David L. Hawksworth (The Natural History Museum, London, & Royal Botanic Gardens, Kew, UK): Revolutionizing the naming of fungi

Although not belonging to the plant kingdom, fungi and fungal-like organisms have traditionally been treated under what was the International Code of Botanical Nomenclature. The nomenclatural needs of mycologists diverge from those of botanists, and the revisions of the Code to deal with issues such as the use of cultures as types and the separate naming of different morphos of the same species had to be addressed. With less than 8 % of the fungal species on Earth named, the priority has been to limit time reworking the names of the past. To that end, in 1981 the concept of “sanctioning” was introduced to protect names in selected key early 19^th century works against any earlier competing names, which was extended in 2017 to cover names on lists developed and approved by specialist working groups, and the mandatory registration of all newly proposed names became a requirement from 2011 – and of new typifications of already existing names from 2019. Further, the name of the Code was changed to the International Code of Nomenclature for algae, fungi, and plants in 2011. It was further agreed in 2017 that provisions in the Code relating only to fungal organisms would be voted on at International Mycological and not International Botanical Congresses and included in a separate Chapter of the Code. This model has enabled mycologists to retain control of matters relating to fungal organisms, while at the same time adhering to the same general principles relating to other groups covered by the Code. The mycologists have thus effected a revolution in how fungal organisms are named but within a much broader general nomenclatural framework. This could perhaps serve as a model to be emulated by, for example, algologists (including cyanobacteriologists) and palaeobotanists which also have special requirements developing dedicated Chapters with provisions debated and voted on at pertinent specialist international congresses.

5. John McNeill (Royal Botanic Garden, Edinburgh, UK): Stability in biological nomenclature

There are two components to stability in biological nomenclature, the material being named and the rules governing the naming. This presentation will address both elements. The rules governing the naming of taxa, accepted groupings of animals, fungi, plants and prokaryotes, are well-established and, in their slightly different ways, provide effective mechanisms to ensure that no names need change except as a result of new scientific research. Unfortunately not all biologists take full advantage of these mechanisms and it is certainly the case that the application of many of them, such as the conservation and rejection of names or the suppression of works, can be very time-consuming and a distraction from biodiversity research. Various initiatives have been proposed to ensure nomenclatural stability in a more efficient way. For names falling under the jurisdiction of the International Code of Nomenclature for algae, fungi, and plants (ICN), provision for lists of protected names (NCUs) was proposed and developed, but, despite such a list (for names of Angiosperm families) having been in the Code since 1961, the proposal was firmly rejected by the XVI International Botanical Congress (IBC) in St Louis in 1999. However, following the adoption by the XVIII IBC in Melbourne in 2011 of the “one fungus one name” rule, this same principle was adopted by providing for lists of names of fungi, protected against unlisted names. Some such lists have been published and others are in active preparation; their success would suggest that the principle might well be reconsidered for all groups falling under the ICN. Recent controversy on the so-called “governance of taxonomy” is focussed on the other component involved in nomenclatural stability, the material being named. The assumption that has been claimed to underpin all conservation policy and legislation that “species are fixed entities” represents a fundamental flaw. It will be argued that all taxonomic groupings are human constructs, useful when they reflect the products of evolution. The concept of species is particularly useful only because very often it does reflect well the pattern of variation found in nature – but, given the diversity of breeding systems and other evolutionary processes, no one set of criteria can possibly define species in a way that usefully reflects variation; indeed in a few evolutionary situations, the concept itself is not even very useful. This does not, however, mean that lists of “accepted” names for particular groups cannot and should not be developed. Some consideration of the history of and prospects for such lists will be given.

6. Thomas Pape (Natural History Museum of Denmark, Copenhagen, DK): Catalogue of Life, ZooBank and mandatory registration of animal names

An unambiguous naming of “things” is vital for human communication, which is essentially why we have scientific names for biological taxa, and why the formation and use of these names are regulated by specific provisions. A Catalogue of Life with the name of those species, for which a scientific name has been established, obviously is able to serve society in many important ways. For a Catalogue of Life to become consistent, authoritative and sustainable, we need to know which scientific names are in existence, and we need mechanisms that will capture newly proposed names. Currently, the CoL contains the accepted name of about 1.7 million extant species, which may be 75% of the named planetary life. These names are assembled from 173 source databases that are individually maintained under various quality assessment criteria.

The International Code of Zoological Nomenclature has recently taken the step to split governance for electronic publications between the scientific works themselves and the official ICZN register (ZooBank; http://zoobank.org/). Currently, the requirement for registration is mandatory only for digital works, but the ICZN is working towards making the registration of all newly proposed scientific names in our official register, i.e., ZooBank, mandatory. Separating a registry-based nomenclature (legislation) from a publication-based taxonomy (science) comes with many advantages, but it gets complicated particularly for those nomenclatural acts where taxonomic relevance and especially taxonomic quality (however measured) is an integral part of those acts.

General Programme