Frequently asked questions

1. Species epithets ending in i/ii

In his monumental work “Bibliographia araneorum” (1945-1961), Bonnet analyzed this case carefully and replaced all “-ii” endings of species epithets dedicated to persons by “-i” (except in original names of persons ending with “i”, e.g. Pavesi, Kulczyński, Canestrini etc.). He also gave an exhaustive grammatical / linguistic explanation (Bonnet 1945: 114ff). The vast majority of arachnologists took over his nomenclature that can now be considered as “common usage”. In 2014/15, when the World Spider Catalog was started in his current web-based format, a discussion came up again whether these endings should be altered to the original spelling, according to ICZN article 33.4. This led to intensive discussions with colleagues from all over the world, unequivocally showing to us that practically nobody wants to alter the names commonly used since Bonnet. Therefore, also for the sake of nomenclatural stability, we decided to leave the names as they are used since 1959 at latest (when vol. 2 of “Bibliographia araneorum” was finalized) by the vast majority of authorities in arachnology. The only exception is Heliophanus kochii because this is covered by a decision of ICZN (1990a: Opinion 1611).

2. Why does WSC not include new faunistic records?

The World Spider Catalog gives a very brief description of the geographic range of a species. This shall provide a general guide and no attempt has been made to ensure that these records are comprehensive. Therefore, new faunistic records will usually not be included. Also, the WSC is not a catalogue or checklist for each country. The taxonomic references are listed, but one cannot find country-wise references in the WSC.

3. Early view status of a publication, DOI links and upcoming papers

For the most recent publications, DOI links are added to the references. In older papers (before 2014) the DOI links are added only cursorial [you may send such additions to]. In the list of the upcoming papers ( articles, which are not published with their final pagination ('early view'), are only listed, when DOI links are active and they are peer-reviewed already. Only papers which have their final pagination will be included into the WSC and are available as PDF for WSCA members.

4. Why are subfamilies, tribes, subgenera etc. not considered in the WSC?

Admittedly, there are several reasons why the inclusion of subgenera, tribes and subfamilies into the World Spider Catalog would be desirable. However, the World Spider Catalog team only has limited financial resources and these are more or less sufficient to cover the present running costs. Including and adapting names of the family- and genus-group other than genus and family names is beyond our current capability. In addition, the World Spider Catalog is a tool for taxonomy, not for phylogenetics of spiders, and in the Introduction chapter of the World Spider Catalog, it is clearly stated that the usage of the World Spider Catalog does not unburden researchers from consulting the classical literature, including the volumes of Bonnet and Roewer, that can be easily accessed through the World Spider Catalog. Finally, we feel that creating too many new superspecific names in the age of highly dynamic phylogenies brings more confusion than stability into spider taxonomy. In the present situation it is more desirable to use terms with no nomenclatural relevance, like species groups instead of new subgenera (e.g. “Pardosa lugubris species group”) and vernacular names for clades (e.g. “spiny leg clade”), and we highly recommend such a usage.

5. Why no colon to distinguish primary and secondary citations?

Article 51.2.1 of the International Code of Zoological Nomenclature recommends that “The name of a subsequent user, if cited, is to be separated from the name of the taxon in some distinctive and explicit manner”. While the citation of the article where the taxon has first been described (primary citation) has to be added without colon or other characters, all other citations (secondary citations) should be separated by a colon or comparable characters. The World Spider Catalog does not follow this article because (1) it is only a recommendation and it may be discussed how meaningful this is; (2) the Code applies only to taxonomic publications, whereas the World Spider Catalog is an internet-based database; (3) neither Roewer, Brignoli nor Platnick followed this recommendation; (4) adding a colon for secondary citations would require too much handwork because this process cannot easily be automatized; (5) however, we believe that the user can easily distinguish between primary and secondary citation.

6. Why are some “grammatically incorrect“ species epithets corrected and some not?

It may be difficult to distinguish if a species epithet is a noun (not declined) or an adjective (declined according to the gender of the genus name). Also the gender of the genus name may be difficult to know if not given by the genus author (see ICZN Article 30, especially It should be kept in mind that the “original spelling” is protected in many cases (ICZN Article 32.3), thus supporting nomenclatorial stability. Further, it is stated that incorrect transliteration or Latinization is no reason to correct a name and the code explicitly allows different writings or formations of the stem of a word (ICZN Article 31.1.). Cases, in which corrections are allowed, are listed in ICZN Articles 32.5 and 34.2. If endings of specific epithets dedicated to persons and built in genitiv are wrong in respect to the gender of the persons, this is interpreted as a 'lapsus calami' (ICZN Article 32.5.1.) and corrected. Other corrections are only accepted by the World Spider Catalog when they are proposed with convincing argumentation in a publication.

7. Why is COI barcoding not useful on genus level?

In many cases COI (cytochrome oxidase one) barcoding is an excellent tool to separate species but it is generally advised, to add other characters, either further molecular markers or morphological pattern. On genus or higher taxonomic level, COI barcoding alone is meanwhile considered as not useful for several reasons:

  • Due to its maternal inheritance as a mitochondrial gene, strong differences between resulting gene tree and real phylogeny have been found (e.g., Edwards & Bensch (2009) Molecular Ecology 18: 2930-2933, doi: 10.1111/j.1365-294X.2009.04270.x)
  • Widely spread endosymbionts such as Wolbachia lead to introgression of mtDNA from other species and falsify the results (e.g., Klopfstein et al. (2016) Zoological Journal of the Linnean Society 177: 541-557, doi: 10.1111/zoj.12380).
  • COI on genus level is usually strongly saturated, making phylogenetic trees unreliable (long branch attraction). Intensive sampling and adding as many taxa as possible may help to counter this a bit (e.g., Quicke et al. (2012) Molecular Ecology Resources 12: 676-685, doi: 10.1111/j.1755-0998.2012.03143.x).
  • Databases such as BOLD or the NCBI databases contain also species that are not correctly identified. Relying exclusively on such databases and/or including low numbers of specimen may result in error-prone and misleading phylogenies.
  • A further good argumentation can be found here:

In conclusion, COI barcoding should be imbedded into a set of other markers and/or morphological data. Intensive sampling, high taxa density and a selection of reasonable outgroups are important. The isolated usage of COI barcoding does not qualify for good laboratory practice, it is therefore rejected by experts in this field, and the WSC will normally not take over such results.

8. Are references listed as a, b, c in chronological order?

If an author produces several publications per year, the World Spider Catalog lists them as a, b, c. This system goes back to Roewer’s catalogue (1942, 1955a) and is not necessarily in chronological order. With more recent publications, we try to keep the chronological order, but this is not always possible. There are several reasons for this: In former times, Roewer did not follow a strict order or the information on the exact publication date was not available. If it turned out (just to give an example) that a publication was not published in December (e.g., as 1963c) but only in January 1964 it had to be moved to 1964 and received the next available letter, thus it could become 1964f. We want to avoid confusion and do not “correct” the sequence within the a-b-c system, once a publication is listed in the WSC. This means that within the a-b-c numeration, you should only conclude that b was published before c, when the publication date on the PDF or other information supports this.