Field of Science


Here are the answers to yesterday's quiz:

1. Current rank-based taxonomy is based on seven primary ranks. Which two were not used by Linnaeus?

Okay, that was an easy one to start off with. Linnaeus didn't use "families" or "phyla" (and for animals, he only recognised six "classes" - mammals, birds, amphibians [including reptiles], fish, insects [including other arthropods] and "worms" [pretty much anything soft and squishy, and not necessarily even worm-like]).

2. What are the five codes of biological nomenclature currently in action?

Mike Keesey even had the titles - International Code of Zoological Nomenclature, International Code of Botanical Nomenclature, International Code of Nomenclature of Bacteria (now the International Code of Nomenclature of Prokaryotes, in light of the increasing tendency not to refer to archaebacteria as 'Bacteria'), International Code of Virus Classification and Nomenclature, and International Code of Nomenclature of Cultivated Plants. The last one, if you were wondering, covers the registration of names for varieties bred in horticulture, such as a cauliflower Brassica oleracea 'Snow Ball'.

3. Name one group of organisms not governed by any of these five codes.

Since the bacterial code went its separate way from the botanical code, fossil prokaryotes have been left effectively homeless. The botanical code no longer regulates prokaryotes except for Cyanobacteria (so those fossil prokaryotes identified as cyanobacteria would still be regulated), while the bacterial code is effectively inapplicable to non-living taxa (it requires deposition of a sample of the living type strain in at least two collections in two different countries for a taxon to be valid). Mike's guess that stem-biotes were the organisms in question is therefore partially correct, because it is possible (albeit probably not ever demonstrable) that a fossil prokaryote could be a stem-biote.

4. What is the earliest publication using binomial nomenclature to be currently recognised by the ICZN?

This was meant to be a trick question, but sadly no-one fell for the trick. While the 10th edition of Linnaeus' Systema Naturae, published in 1758, is the official starting point for binomial nomenclature under the ICZN, Andreas Johansson correctly pointed out that one earlier publication, Clerck's 1757 Svenska Spindlar uti sina hufvud-slågter indelte samt under några och sextio särskildte arter beskrefne och med illuminerade figurer uplyste - Aranei Svecici, descriptionibus et figuris æneis illustrati, ad genera subalterna redacti, speciebus ultra LX determinati (usually referred to simply as Aranei Svecici, for obvious reasons), has been accepted by the ICZN as admissible (and officially takes priority over Linnaeus). You can read the entirety of Aranei Svecici online through this site.

5. When and what was the earliest formal zoological nomenclatural code proposed? What was the earliest botanical code?

Mike did refer to the 1842 Strickland Code, but unfortunately for Mike the object of the Strickland Code was zoology, not botany. As I previously alluded to at the beginning of an earlier post, botanists at the time rejected the idea of extending the Strickland code to cover their territory (the open-access article linked to at that post also transcribes a large part of the Strickland Code, for anyone interested in reading it). The first Botanical code to be formally adopted was the Lois de la Nomenclature Botanique published by Alphonse de Candolle in 1867. Ironically, while the zoologists had a twenty-five-year head-start over the botanists in establishing a code, it was the botanists that actually paid attention to theirs, while the Strickland Code ending up largely falling by the wayside. As such, botanical nomenclature ended up becoming a lot more stabilised a lot earlier than zoological nomenclature.

6. What do the letters 'VP' and 'AL' mean as part of a bacterial name?

Originally, bacteria were dealt with using the Botanical Code, but as time went by it became increasingly clear that the provisions of that code were not suitable for working with prokaryotes (which are mostly distinguished by chemical rather than physical characteristics), with thousands of excess names for bacterial taxa having been proposed for which no-one had the slightest idea to what they referred, and eventually a separate Bacterial Code was established. Those bacterial taxa that had been well-characterised were listed in the Approved Lists of Bacterial Names, published in 1980, and any taxa from before 1980 that were not on the Approved Lists were effectively null or void. Any bacterial name published after 1980, in order to be valid, had to be either published or validated in the International Journal of Systematic Bacteriology (now the International Journal of Systematic and Evolutionary Microbiology). To indicate the mode of validation, the full citation for a bacterial name will have the letters 'AL' or 'VP' as a superscript against the publication date - 'AL' indicates a name was on the Approved Lists (in which case it takes priority from the original date of publication), while 'VP' (for 'Valid Publication') indicates that it was validated by publication in the IJSEM (in which case it is dated from it appeared in that journal, no matter how much earlier the name may have appeared elsewhere).

7. Kathablepharis and Katablepharis are different spellings for the name of the same organism. Each is the one spelling that must be used, while the other spelling is invalid. Explain.

Mike was halfway there with this one - Katablepharis is a protist that has been treated by different authors using both the zoological and botanical codes. Its name was originally published as Kathablepharis by Skuja in 1939, but the correct Latinisation should have been Katablepharis. In such cases, the botanical code requires that the name be corrected, but the zoological code requires that the original spelling be maintained. Hence the correct name of this organism ended up being spelt differently depending on which code it was being treated under.

8. The name Oedicnemidae was published by Gray in 1840. The name Burhinidae was published by Mathews in 1912. Both refer to the same family, for which the valid name is Burhinidae. Why?

Okay, take a deep breath. This one gets a little involved, but the situation it refers to is actually not that uncommon. Genus- and species-level nomenclature can be confusing enough, but sometimes family-level nomenclature is just plain evil.

It used to be the tradition that when the type genus of an animal family was synonymised with another genus, the name of the family also changed to match. So when Oedicnemus was synonymised with Burhinus, Oedicnemidae became known as Burhinidae. Where this gets confusing is that the altered name continued to take its priority from the original name - so the name Burhinidae would be treated as dating from 1840, when Oedicnemidae was published, even though the name Burhinidae itself never actually existed until 1912. When the modern Zoological Code was first published in 1961 (well, before that, even), it was realised that this was far too complicated and confusing a way to do things (especially in cases of debated synonymy), and so the current rule was introduced that family names were determined only by their own priority, and the synonymy of its type genus did not affect the validity of a family name. However, because the ICZN does not mess with past actions when introducing new rules, if a family name was changed under the old tradition before 1960, it retained the new name. So the then-current name Burhinidae stayed Burhinidae, and didn't have to revert to the probably long-forgotten name Oedicnemidae.

9. If two or more taxa have the same name, and fall under the scope of the same code, then their names are homonyms, and only one can be valid. Pupa affinis Rossmaessler 1839, Pupa affinis Aradas & Maggione 1843 and Pupa affinis (Adams 1855) are all names for animals, but they are not considered homonyms. How is this possible?

Mike got this one right off the bat. The three names are not counted as homonyms because they are not actually in the same genus - they are in three different genera that had each been named Pupa. The genus names have to be corrected because they are homonyms, but the species that were published in association with those genera can keep their original names.

Picture credits (from top to bottom): Dante being examined on theology in heaven, from Il Paradiso, via here.

The Beaver's Lesson, from The Hunting of the Snark.

Examition of a Witch, by T. H. Matteson, via here.

"Lojban" from xkcd.

Satan in Heaven, from Paradise Lost, via here.


  1. Quick clarifying question -

    You state in the answer to #9: "The genus names have to be corrected because they are homonyms, but the species that were published in association with those genera can keep their original names"

    You are suggesting that (hopefully) someday the three different organisms will have different genera, but will keep the same species epithet?

  2. Five out of nine! Damn, that was hard.

    (And the reason I have the codes' titles memorized is because they're some of the only "authorities" in the database of my Names on Nodes project at present.)

    Interesting on #8.

  3. Jim: Yes, that is what I meant (though I expect the replacement genera names are already out there). Sorry if I wasn't clear.


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