Insights from Zootaxa on potential trends in zoological taxonomic activity
© Tancoigne et al; licensee BioMed Central Ltd. 2011
Received: 19 October 2010
Accepted: 18 March 2011
Published: 18 March 2011
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© Tancoigne et al; licensee BioMed Central Ltd. 2011
Received: 19 October 2010
Accepted: 18 March 2011
Published: 18 March 2011
An opinion currently shared by taxonomists and non taxonomists alike is that the work of inventorying biodiversity is unbalanced: firstly, in favour of countries in which taxonomy has been studied for a long time, and, secondly, in favour of vertebrates. In the current context of threats of species extinction, access for taxonomists to biological material and information becomes crucial if the scientific community really aims at a better knowledge of biological diversity before it is severely and irreversibly impoverished. We performed an analysis of 748 papers published in Zootaxa in 2006 and 2007, as well as 434 questionnaires sent to their authors to test these opinions. A generalization of these results to zoological taxonomy as a whole is discussed.
We found that the disequilibrium is not exactly what it usually considered to be. The USA, China and Brazil are currently the three leading countries in zoological taxonomy. Each of them presents, however, a different pattern. Taxonomists from Asia and South America are younger and mainly work in universities, not museums. A bias in favour of vertebrates still exists if we refer to the effort invested in each group to produce taxonomic data, but not to the number of papers. Finally, we insist on the idea that "describing a species" is very different from "knowing a species".
The taxonomic involvement of a country, in terms of manpower and funding, appears to be a key factor in the development of fruitful taxonomic research. This message seems to have been understood by the countries that recently decided to increase considerably their taxonomic involvement. It still has to be received by those who did not.
Taxonomy is the disciplinary field of biology in charge of collecting, studying, describing, classifying and naming living organisms and taxa. It is a fundamental discipline for biology as a whole. It is thus crucial that taxonomists be given access to biological material and information. Previous studies [1–4] and widespread opinions [5, 6] nevertheless postulate that access to specimens is unbalanced, both as regards the different regions of the world and the taxonomic groups. First, countries and areas where researchers have historically worked for a longer time on zoological taxonomy (Europe, North America and Australia) would therefore dominate zoological taxonomy. Second, the attention paid to Vertebrata would be higher than for other taxa, especially Arthropoda.
Yet, a quick search of all papers describing new species in the Web of Science in 2006 reveals that Brazil and China are among the top five publishing countries (USA: 25%, China: 13%, Germany: 8%, Japan: 7%, Brazil: 6%).
So, as concerns the distribution of zoological taxonomy, where are we now? No recent quantitative study exists at the world scale. Such surveys were either limited to a taxon [3, 7–11], or a country [12–22], or they offered a summary of fragmented information [23–25].
However, today a mega-journal of taxonomy, Zootaxa, provides a worldwide coverage and deals with numerous zoological taxa. In 2004, it published far more pages than the combined total published in the ten core journals in systematic zoology . It contributed 13% of all new taxa of animals indexed in the Zoological Record since 2004 . An analysis of this journal could therefore produce a useful and relevant insight on today's taxonomical practices in zoology.
Is zoological taxonomy still mostly practised in countries that have historically been taxonomically active?
Is zoological taxonomy still unbalanced in favour of vertebrates, vs. arthropods?
In conclusion, we will discuss the possible generalization of our results to taxonomy as a whole.
We determined the countries and areas in which (1) more works are published in zoological taxonomy; (2) most of the active taxonomists are working; (3) foreign taxonomists are mainly received; (4) taxonomists are involved in collaborations; (5) more species are described from other areas; (6) types specimens are kept; and, finally, (7) research is carried out in museums, which are traditional institutions for taxonomic research [9, 15, 28–30].
The disequilibrium in favour of vertebrates can be documented in terms of either taxonomic production (publications, pages, new species), or in the means employed for the studies (number of taxonomists, of specimens, of characters...). Therefore, we gathered additional information on (8) the taxa to which are devoted the higher number of publications, pages, new species as well as the taxa represented by the highest numbers of (9) taxonomists, (10) characters and (11) specimens used.
We chose to work on the years 2006 and 2007 because they were those when most articles had been produced at the time of our study (n = 2138). We randomly selected 748 articles among all those published in Zootaxa during this period. We devised a method to fix the sampling size. This method is explained below. Then we used three main procedures to obtain the data from our sample: data extraction from literature, data mining on databases and a questionnaire sent to each author of the sample who had provided an email. The data obtained from the articles or the questionnaire were entered into a database built using Access2002.
The 748 articles studied were written by 1778 authors. Once multiple authorships were removed, 1384 authors remained, 1025 of whom had mentioned an e-mail address in the paper. A questionnaire had been sent via e-mail in May 2008 to 10% of these 1025 authors for a preliminary study. It received 56 answers and comments from authors from most parts of the world (except Africa). Our questionnaire was considered approved and it was then sent once again in May 2009 to the 939 remaining authors. It was rejected by 105 mailboxes and received 434 answers in all (56 in 2008 and 378 in 2009). Its answer rate was thus 47%. We used EmailQuestionnaire software to send our questionnaire .
Data extracted for each article, author, institution, new species and specimen involved
ZR ID number
Number attributed by the Zoological Record
Internet link to the pdf article on the Zootaxa website
Number of pages
n = (ending page - beginning page) + 1
ZR + H
Delay of publication
Number of days between acceptance and publication
ZT + H
Category of document
Category of work
We distinguished six categories of works. additional data: addition of sounds, karyotypes, redescriptions, chorology, phylogenies to the knowledge of a taxon, without new taxon description; checklists or catalogue of species/types; regional fauna: taxonomic revision at regional scale; taxonomic revision: each taxon or types reviewed, or at least 3 different kinds of analyses done (e.g. morphological studies plus distribution plus karyotype of a taxon); taxonomic work on isolated taxa: single or multiple descriptions of new taxa, new descriptions plus new records of the taxon; theoretical works: biographies or nomenclatural changes only, or theoretical work on taxonomy and nomenclature
Whether authorship is in alphabetical order or not. Names beginning by "De", "Van", are considered at letters "D" or "V".
Phylum as provided by ZR indexation
The most inclusive taxon treated in the article
Level of work
Level of the most inclusive taxon treated in the article. Species level: any level up to and including species level; genus level: any level from species level up to and including genus level; family level: any level from genus level up to and including family level; above family level: any level above family level
The most single inclusive area treated in the article. We used political boundaries of studied areas instead of biogeographical ones, in order to study the relationship between laboratories and studied areas
Level of geographic delimitation
We used four levels of area: locality level, regional level, country level, major area level. We used other when the study involves more than one major area. Oceans and seas were treated as regions and affiliated to a country or a continent when specified in the article
Number of references
Whether the article is in free access or not
List of the articles written by the author in Zootaxa
Position in the article
Institution of the author for the paper concerned. The ZR provides the address of the first co-author; the other ones were added from the paper itself. Whenever the author is affiliated to several institutions, this information was retained
ZR + H
Some email addresses were provided by the ZR; others were found in the article
ZR + H
Amateur, Doctoral student, Established taxonomist researcher, Established non-taxonomist researcher, Master student, Postdoctoral, Retired researcher, Technician
Country of birth
Master (four or five years of faculty), PhD (or equivalent), Other, No degree
The names of all institutions were checked to suppress duplicates
ZR + H
Five categories of institutions were recognized: Museum, University, Institute, Private, Other institution
ZR + H
The affiliation of a country to a major area followed the CIA World Factbook data 
Level of the institution
Some institutions are subordinate to others, which may (or may not) appear in the address given by the author(s). For each of them, the following information was checked using their web sites:
1: whether the institution is autonomous
2: whether it is subordinate to another institution
3: whether it is subordinate to two other institutions
Name of the superordinate institution if relevant
List of the specimens involved
Whether allotypes are designated or not
Whether numerous developmental stages are involved or not
Methods used for tree construction
Parsimony, Bayesian/maximum likelihood, Distance, Combined methods
Morpho-anatomical, Molecular, Bio-acoustic, Karyological, Other
Specimens used to describe a new species
Number of specimens
Number of specimens of each type for each new species
Kind of specimen
Holotype, Syntype, Neotype, Paratype, Other specimen
Place of collect
Collecting locality as stated in the paper, with GPS coordinates if available. Localities were distinguished through their names or through their GPS coordinates. Each locality was referred to a country and a realm whenever possible. The geographical delimitations used are the same as for the publications
Institution of conservation
Institution where specimen(s) is/are kept
Year of collect
For holotypes only
For holotypes only. Male; Female; Hermaphrodite; Unknown when the information is lacking. Because many authors do not indicate the sex when they use juveniles, we also added the category Juvenile
Each country was affiliated to a region through the data of the CIA world factbook . Major regions are abbreviated the following way: Af (Africa), As (Asia), E (Europe), M (Middle East), N (North America), O (Oceania), S (South America). Given the small amount of papers from Central America, this region was grouped with South America.
Authors (i.e. names on paper) and taxonomists (i.e. real persons) were distinguished. For example, a taxonomist who writes two articles represents two authors.
The number of publications per major region or country was computed fractionally. For example, an article written by two authors from Asia and one author who mentioned two addresses, one in South America and one in Africa, counts for 0.5 for Asia, 0.25 for South America and 0.25 for Africa. The number of publications per category of institution was also calculated fractionally. For example, an article written by two authors from the University of Sao Paulo and one author who mentioned two addresses, one in the University of Sao Paulo and one in the American National Museum, counts for 0.75 for Brazilian universities and 0.25 for North American museums. The number of type-specimens per category of institution is calculated directly. For example, a new species with one holotype kept in the University of Sao Paulo and 54 paratypes kept in the American National Museum counts 1 for North American museums and 54 for Brazilian universities. The number of taxonomists per major region or country was calculated fractionally once duplicated authors (authors with same name and address) had been removed. For example, if an author mentioned two addresses in two different major regions s/he counts 0.5 for each region. The collaboration indicator of the Observatoire des Sciences et des Techniques (Paris, France) was used to study collaborations: (number of publications of a region A with an other region B)/(total number of publications of region A). For instance, an article written by one author from Asia and two from South America counts for one co-publication between Asia and South America.
All the data was analysed with the free statistical software R  and packages ade4 , RODBC , vcd [37, 38] and FactoMineR . We used correspondence analysis (CA) to summarize the data's structure and identify similarities between the variables of a contingency table . CA measures the distances between the row and column points and presents the inter-relations of variables in calculated dimensions that outlines maximum of variance (VARIMAX rotation). The analysis determines which category values lie close together and which are far from each other. These can be seen on a correspondence map, where the row and column categories are plotted along the computed factor axes. Spatial proximity between categories does not imply a correlation between the categories but instead a strong specific link in relation to these factors. This graphical method is based on a χ2 test that measures the deviation to independence model. We also performed χ2 statistical tests to compare proportions when it was needed.
Our choice to work on Zootaxa inevitably represents a bias. Because our questions treat the different areas of the world and taxa, two possible biases concern the representativeness of (1) the taxa studied in Zootaxa and (2) the regions where the studies were carried out.
Publications dealing with species are predominant in Zootaxa (74% of the works analysed). Only 17% of the papers deal with taxa between genus and family, and 9% with taxa above family level. Therefore, so-called "α-taxonomy", "microtaxonomy" , or "eidonomy"  is predominant. Works on isolated taxa (single species descriptions, etc.) are the most numerous (57%), followed by taxonomic revisions (17%), additions of new data for taxa already known (11%), regional faunas (8%), checklists or catalogues of species/types (4%) and theoretical works (3%). These terms are defined in Table 1.
Dimension 2 separates M from the other categories because no individuals belonging to the (65, 90] category answered our questionnaire. The supplementary data show that the (25, 35] category was related to technicians and postdocs, whereas (55, 65] was related to established taxonomic researchers, established non-taxonomic researchers and amateurs. These data suggest that the population of taxonomists is younger in As and S.
Let us now consider the twelve questions that we posed above.
Relationships between studied regions and regions of researchers' labs
Studying regions (%)
Studied regions (%)
The number of publishing taxonomists per country is the highest for Europe (27%), then for South America (24%), North America (21%) and Asia (20%). Germany is the first country of Europe (20%); Brazil is the first country of South America (61%), the USA of North America (79%) and China of Asia (51%).
Concerning geographic mobility, 10% of the 427 authors who answered the question were not working in their country of nationality. Most were fully qualified researchers (69%), followed by predoctoral students (29%) and postdoctoral students (9%). Europeans are those who move the most (53%). Europe and North America are the areas with the highest rates of authors originating from other areas (37% and 25%, respectively). Unfortunately, our results on taxonomists' mobility do not allow us to know whether the weak mobility of taxonomists from Asia and South America to Europe, North America and Oceania is due to short-term mobility (which cannot be measured from our data) or to a more general lack of mobility.
Authors from ENO area do not predominantly sign the publications as first authors (χ2 test, P = 0.054).
The percentages of single-author articles is greater in ENO (28%) than in AsS (12%; χ2 test, P = 9.49e-08).
From a zootaxonomic point of view, Asia and South America are the most studied regions (see Table 2-B). Altogether they account for 50% of the publications and 61% of the new species. Latitudes are provided in the publications for 667 of the new species. Most of them (77%) come from latitudes higher than 10°, equally distributed between North and South. The remaining 23% are also equally distributed North and South (χ2: P > 0.05).
The supplementary data of Figure 6 show that holotypes are not always kept in the areas they come from. Authors from ENO area keep their holotypes as well as the holotypes from Africa and Middle East which they have studied in collaboration. On the other hand, authors from Asia and South America keep their holotypes even if studied in collaboration with authors from Europe, North America or Oceania.
The proportion of museums in authors' affiliation decreases to 33% (AfEO), 3% (AsM) and 7% (SN) when the institution that subordinates the museum is taken into account. The proportion of universities also increases to 44% for AfEO, 70% for AsM and 67% for SN.
Noteworthy is the high proportion of museums (55%) and private collections (21%) for AfEO. 28% of the types kept in European private collections are holotypes and syntypes; 72% are paratypes.
Proportion of publication and new species for each taxon
% of publication
% of new species
It is thus not surprising that newly described species are mainly arthropods (81%) and vertebrates (8%). Many (51%) of the new species are described in taxonomic revisions, and only 35% in isolated works.
The supplementary data of Figure 8 show that the category Arthropoda is linked to few authors categories, whereas Vertebrata is linked to categories with more than three authors.
In the Vertebrata, a new species is described on average by 3.4 authors, whereas the figure is 0.9 in the Arthropoda. Thus, for an equal number of taxonomists, taxonomists working on arthropods describe more new species than taxonomists working on vertebrates.
The supplementary data of Figure 8 show that the variety of characters used to describe the new species is higher for vertebrates. Whenever non-morphological characters are used in Vertebrata descriptions, these are mainly molecular or bio-acoustic.
No significant difference between taxa was found in this respect. One species out of five was described from one specimen only (20%), or known from one locality only (21%). As much as 53% of the new species were collected from more than 2 localities. Two species out of five were described from specimen(s) of one sex only. Nine species out of 10 were described on the basis of a single stage of development (no significant difference between taxa). These figures vary when the year of collection is taken into account. New species known only from 1 specimen represent 64% of the new species with holotypes collected before the median year 1999. They represent 33% of the new species with holotypes collected after 1999 (n = 1261, P = 5.83e-08).
This study of Zootaxa's 2006-2007 publications supports the idea that zoological taxonomy is still more developed in countries that have historically been taxonomically active. Taxonomists from Europe, North America and Oceania are the only ones to collaborate largely with those from other regions, and they do so with all regions in the world. They also remain the only ones to work on very wide geographical zones and to host researchers from abroad. A lack of studies in Africa has already been pointed out [11, 25, 43]. This lack still exists, as African regions are not well represented in our sample.
However, this study also shows that Asian and South American countries appear to play a prominent role in zoological taxonomy today. Their high number of publications, the fact that they keep their own specimens and the median age of their respondents show that they have a developed and active community of taxonomists. Previous studies on taxonomists' age could not be used for a rigorous comparison because the enquiries were not carried out at the same time [15, 20, 23, 28, 44–46].
Are these results artefacts created by our choice of the journal Zootaxa? We do not think so, for several reasons. First, we previously checked that our sampling was not biased questioning this respect. Second, the taxonomic growth of the two main countries responsible for these results (China and Brazil) has already been pointed out in the literature [10, 47]. China's funding for research increased by 30% each year between 1998 and 2006, which benefited taxonomy: "The evaluation of the funded projects in the Division [of Zoology] shows that animal morphology and taxonomy are the main supported areas, accounting for half of the total funded" . In 2004, China became the fifth country in terms of number of publications. The number of students has been increasing everywhere in this country . An analysis of Brazil's scientific production carried out by The Observatoire des Sciences et Techniques (Paris, France) showed that it was quickly growing [50, 51]. The figures were even underestimated: a bibliometric study  showed that many Brazilian articles are published in Portuguese, in national journals. Thus they were not included in the calculation. Moreover, a recent study on amphibian taxonomic effort and expertise supports these results concerning China and Brazil . It also found that the continental distribution of authors in Zootaxa (n = 5663) was similar to the continental distribution of authors working on a given taxon (i.e. Amphibians, n = 647).
Another argument in favour of this idea involves the geographical origin of the new species. Surprisingly, no latitude preference was identified regarding the origin of the newly described species. This contradicts the widespread idea that latitudes close to the equator have a richer biodiversity . Why, then, do our data fail to find high proportion of new species in the belt of 10° above and below the equator?
In this respect we found that places where the highest numbers of species were described recently (China, Brazil) are also those with the highest number of taxonomists. A correlation exists between the number of taxonomists and the number of species known in a phylum . It is thus likely that the high number of newly described species in China and Brazil is a reflection of the taxonomic involvement of these countries, in terms of manpower and funding. Thus, if China and Brazil appear to be the most studied regions, this is not only because they are large countries with a rich biodiversity [55–57], but also because they have numerous taxonomists and have decided to invest in this branch of research.
Finally, it is striking that a high proportion of our respondents were professionals (fully qualified researchers, students) despite the high number of amateurs in entomology . Zootaxa would therefore reflect a biased sub-sample of the taxonomic community, including mostly professionals. One may wonder whether part of this phenomenon might be due to the fact that some amateur taxonomists, especially in entomology, tend to publish their works in their national languages in national periodicals whenever they still exist . Unfortunately, professional categories are not expressed the same way between studies, hence our figures are hardly comparable with previous works [15, 24, 28, 54]. We also have to keep in mind that the authors who provided their email addresses are mainly the corresponding authors - a factor that might influence our results.
On the basis of taxonomic output (number of publications, number of new species), arthropods, especially insects, appear to be much more studied than vertebrates. Vertebrates nevertheless concentrate a higher number of taxonomists, characters and methods used for each new species. Thus, even if more results are produced on arthropods, their study involves a lesser amount of means (number of taxonomists, number and diversity of methods used).
The long-studied vertebrates [2, 59] are nowadays studied with modern methods. Most of the time, these methods complement the morphological ones. As a consequence, morphological studies are a necessary step in any taxonomic work. They are not a sign of intellectual or technological backwardness when presented alone . They are a strong indication of the amplitude of our ignorance of the taxon in question. The data we gathered on the numbers of specimens, localities and kinds of characters used to recognize and describe a new taxon clearly show that we are very far from "knowing" a species once it has been "described" and named .
Moreover, the taxa which benefit from a high taxonomic involvement have nevertheless the lowest rates of description of new species. If we aim at increasing the number of known species as quickly as possible, taxonomists should give priority to taxa which do not require these new methods.
We do not think that these results are artefacts created by our choice to work on the journal Zootaxa. We previously checked that our sampling was not biased for this question and we already know that vertebrates have been studied for a longer time [2, 59]. Our observations match this idea.
This disequilibrium of the taxonomic effort in favour of vertebrates is problematic if we aim at better knowing that which we know the least. Insects represent 58% of the new described species and vertebrates 7.2%. Yet, according to some estimates (figures computed from the sum of the 'World Descr.' and 'Estimate World' figures for chordates and invertebrates in ), vertebrates would only represent 0.3% of the numbers of species that remain to be described, whereas insects represent 74%. Thus, this distribution of taxonomic effort between taxa is unsuitable when considering the needs [16, 23, 24, 54, 62]. The international and national scientific communities should hire more people to focus on arthropods, especially entomologists.
The nature of the works published in Zootaxa show that this journal gives priority to alpha-taxonomy. "Zootaxa considers papers on all animal taxa, both living and fossil, and especially encourages descriptions of new taxa" . We therefore consider our main results valid for zoological alpha-taxonomy.
We found that the disequilibrium does not correspond exactly to that usually admitted. The USA, China and Brazil are currently the three leading countries in zoological alpha-taxonomy. However, each of them presents a different pattern. Taxonomists from Asia and South America are younger and mainly work in universities, rather than museums. A bias in favour of vertebrates still exists if we refer to the effort invested in each group to produce taxonomic data, but not for the number of papers. Finally, we insist on the idea that "describing a species" is very different from "knowing a species". The taxonomic involvement of a country, in terms of manpower and funding, appears here to be a key factor in the development of fruitful taxonomic research. If we aim at increasing our knowledge of the species of the world, we still have much efforts to make in terms of the efficient distribution of the taxonomic effort between taxa.
We thank all those who took time out of their already busy schedules to fill in and return the questionnaire. Thanks to Zhang Zhi-Qiang, who encouraged this study, provided free access to Zootaxa's articles and provided critical comments on the work. We would also like to thank Sébastien Ballesteros, Julien Barnier and Gaël Millot for their statistical help. If any statistical mistake can be found in this paper, it must nevertheless be attributed to the authors. We would like to thank Sandra Dos Santos for her translations of the Portuguese papers and Annie Amirda, Julie Delacôte and Mark Judson for the English corrections. We would also like to thank Philippe Grandcolas, Aurélien Miralles, Antoine T. Mantilleri, Ferdinando Boero, Mark Judson and four anonymous referees for their critical comments.
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