No single list of all the world’s species’ names has been agreed by scientists. Some taxa have no list, and some, especially the more popular mammals and birds have several. In a recent paper, we proposed a plan to address this that involves collaboration between the species experts (taxonomists) and users. Users include the taxonomists themselves and people managing pests and pathogens, food products from agriculture, aquaculture and fisheries, ecologists, conservationists.

Because species have been described in thousands of publications, sometimes the same species has been described many times with different names, it has been difficult to track how many species have been named. New databases, like the World Register of Marine Species (WoRMS) and Catalogue of Life (for all species), have brought considerable order to the names. Now, almost all (85-90%) valid names are in one place and their status can be studied. However, partial alternative lists exist in older literature and unpublished which may differ in which names they apply to particular species and may ‘split’ or ‘lump’ species.

Especially in popular groups like birds and mammals, experts may argue about whether similar organisms are one or more species. In other cases, users are unaware of the latest updates to species taxonomy and/or fail to apply the correct names. This is important because one of the species may be threatened with extinction but if lumped with another or considered a sub-species it may be overlooked. While waiting for further research to clarify the species relationships between disputed species, this paper proposes a way for the scientific community to work together to provide the best advice to those who use species names, such as in trade, agriculture, fisheries, pest management, and nature conservation.

The plan does not try to freeze names because of the nature of scientific discovery. Rather it recognises the need for transparency and traceability of information on what species exist and how they are named and encourages more research into Earth’s biodiversity. It sets out ten principles for how a world list may be governed so as to provide timely advice on the application of species names.

Abstract of the paper “Principles for creating a single authoritative list of the world’s taxa”

“Lists of species underpin many fields of human endeavour but there are currently no universally accepted principles for deciding which biological species should be accepted where there are alternative taxonomic treatments (and by extension which scientific names should be applied to those species). As improvements in information technology make it easier to communicate, access and aggregate biodiversity information, there is a need for a framework that helps taxonomists and the users of taxonomy decide which taxa and names should be used by society, while continuing to encourage taxonomic research that leads to new species discoveries, new knowledge of species relationships, and the refinement of existing species concepts. Here we present ten principles that can underpin such a governance framework, namely

(i) Species lists must be based on science, and free from non-taxonomic considerations and interference;

(ii) Governance of species lists must aim for community support and use;

(iii) All decisions about list composition must be transparent;

(iv) The governance of validated lists of species is separate from the governance of the names of taxa;

(v) Governance of lists of accepted species must not constrain academic freedom;

(vi) The set of criteria considered sufficient to recognise species boundaries may appropriately vary between different taxonomic groups but should be consistent where possible;

(vii) A global list must balance conflicting needs for currency and stability by having archived versions;

(viii) Contributors need appropriate recognition;

(ix) List content should be traceable;

(x) A global listing process needs both to encompass global diversity and accommodate local knowledge of that diversity. We conclude by outlining issues that must be resolved if such a system of taxonomic list governance, and a unified list of accepted scientific names generated, are to be universally adopted.”

Examples

A common misconception is that experts disagree, but actually there is no dispute about the vast majority of species. However, emotions can run high when charismatic species of conservation importance are involved, such as giraffes, antelopes and elephants:

The photo with two animals is from Kenya and shows the reticulated giraffe G. c. reticulata. The photo with the eight animals is from Namibia (Angolan giraffe). As a subspecies it is called Giraffa camelopardalis angolensis. Depending on the taxonomy, the two are also considered distinct species as Giraffa angolensis and G. reticulata respectivly. Giraffe taxonomy is being debated, with the traditional classification recognizing a single species and other classifications recognizing up to eight distinct giraffe species. Photographs: Frank E. Zachos (Angolan giraffe: Namibia, 2010; Reticulated giraffe: Kenya, 2013). The photographs can be published under the Creative Commons by Attribution License (CC-BY).

Klipspringer was once one species with 11 sub-species, but now may be several species.  Photo: Frank E. Zachos, CC-BY.

Depending on which source you go to you may find African elephants considered one species or two: the African bush elephant (Loxodonta africana) and forest elephant (Loxodonta cyclotis). The WWF and IUCN only recognise one Loxodonta africana. Wikipedia recognises two. Photo: Frank E. Zachos, CC-BY.

Asian elephants, Elephas maximus in Kuiburi National Park in Thailand. It has been shown that the Borneo pygmy elephant is distinct genetically and physically from other Asian elephants (above photo), and thus should be called sub-species E. m. borneensis or perhaps species E. borneensis. Yet most online websites still consider it a population of Asian elephants E. maximus (which has two subspecies E. m. indicus and E. m. sumatrensis). Photo: Frank E. Zachos, CC-BY.

Reference

Garnett ST, Christidis L, Conix S, Costello MJ, Zachos FE, Bánki OS, Bao Y, Barik SK, Buckeridge JS, Hobern D, Lien A, Montgomery N, Nikolaeva S, Pyle RL, Thomson SA, van Dijk PP, Whalen A, Zhang Z-Q, Thiele KR. 2020. Principles for creating a single authoritative list of the world’s species. PLoS Biology 18(7): e3000736. https://doi. org/10.1371/journal.pbio.3000736

University of Auckland media release