Eva van Emden, Freelance Editor

Certified Copy Editor and Proofreader

eva@vancouvereditor.com

March 14, 2011

Science writing and editing: How to write scientific names

The Latin scientific name of a species, be it plant, animal, bacterium, fungus, etc., is a two-part name consisting of the genus name first (by the way: one genus, two genera) and the species name second. For example, the domestic cat is known as Felis catus. Although the genus name can be used on its own (there are several other species in genus Felis, for instance the wildcat, Felis silvestris), the species name never appears on its own.

The basic rule for writing a scientific name

  1. Use both genus and species name: Felis catus.
  2. Italicize the whole name.
  3. Capitalize only the genus name. (In the past you would capitalize the species designation if it was derived from a proper name, e.g., Megalonyx Jeffersonii, but now the species designation is always lowercased: Megalonyx jeffersonii.)

Rules for abbreviating the genus name

After the first use, the genus name can be abbreviated to just its initial: F. catus.
  1. When a section of the text might be displayed on its own, you might want to spell out the name in full the first time it appears there. For instance, some academic journals require that you write out the genus in full the first time it is used in the abstract, and in all tables and table captions.
  2. When you introduce the name of another species in the same genus, you can use the abbreviated genus name for the new species:1 The domestic cat is species Felis catus. Both F. catus and its wild relative, F. silvestris . . .
  3. If you are discussing two species that belong to different genera that nevertheless start with the same letter, say, Leopardus pardalis, the ocelot, and the Canada lynx, Lynx canadensis, it is better not to abbreviate their genus names.
  4. Abbreviations of more than one letter: I’ve seen a few instances of two-letter abbreviations of genus names, for instance Au. afarensis and Ar. ramidus for Australopithecus afarensis and Ardipithecus ramidus, and I’ve seen discussion of two- or three-letter genus abbreviations for some taxonomic groups. Butcher’s Copy-editing2 says they are to be avoided, but they’re permissible to avoid ambiguity.3 I recommend checking with your target publication to see whether they allow this style.
  5. Sometimes the full genus name isn’t spelled out on first use. Some organisms, such as the famous study organisms E. coli and C. elegans, are so well known that it’s common in informal discussion to just use the abbreviated version of the name.

Names of taxonomic levels above the genus level

The names of higher taxonomic levels (family, order, class, phylum or division, and kingdom) should be capitalized but not italicized (see Chicago 8.125 and Butcher’s 13.5.1). Common names derived from taxon names, for instance “felines” for members of the family Felidae, are not capitalized. A common name that is derived from a genus name, such as gorilla, is not capitalized either (see Chicago 8.126).

Names of taxonomic levels below the species level

Below the level of species there are subspecies and varieties.
  1. The subspecies name is italicized.
  2. In zoology, the subspecies is not indicated by any label; it just follows the species name: the European wildcat is Felis silvestris silvestris. If the subspecies name is the same as the species name, it can be abbreviated: Felis s. silvestris.
  3. In botany, the subspecies is indicated by “subsp.” or “ssp.” (Butcher’s recommends subsp.4): Juncus effusus subsp. solutus. The “subsp.” label is not italicized.
  4. The name of a variety is italicized, but the “var.” label is not: The insecticide BTK is produced by Bacillus thuringiensis var. kurstaki.

Unknown or unspecified species

When referring to an unidentified species, use the abbreviation “sp.”: The meadow contained several sedge plants (Carex sp.). The plural form is “spp.”: The forest floor contained several species of pixie cup lichen (Cladonia spp.). The “sp.” and “spp.” labels are not italicized.

The species author and the sp. nov. tag for introducing new species in the literature

When a species is being formally introduced in a scientific paper the name of the author (the person who first described the species in academic literature) is usually given.
  1. The author name is not italicized: The straightleaf rush is Juncus orthophyllus Coville.
  2. The name may be abbreviated. Carolus Linnaeus, a biologist who is such a hero his name was Latinized, gets the abbreviation “L.”: The European meadow rush is Juncus inflexus L.
  3. If the author name is in parentheses, that indicates that the species was originally assigned to a different genus.
  4. The abbreviation “sp. nov.” indicates that a species is being introduced in the literature for the first time. Do not italicize “sp. nov.”: “Pyrococcus furiosus sp. nov. represents a novel genus of marine heterotrophic archaebacteria growing optimally at 100°C

References

Chicago Manual of Style

More help with writing scientific papers

For some more help with formatting and style in scientific writing, see “Making your science papers look good.”

Notes

1 Butcher’s Copy-editing 4th Edition, p. 328
2 Judith Butcher, Caroline Drake, and Maureen Leach, Butcher’s Copy-editing, 4th Edition. Cambridge University Press, 2006. ISBN: 9780521847131
3 Butcher’s Copy-editing 4th Edition, p. 328
4 Butcher’s Copy-editing 4th Edition, p. 329

27 comments:

  1. Thank you so much for this valuable resource!

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  2. Thanks for the reference. Fyi, it's Canada lynx, not Canadian lynx. The same is true for the Canada goose.

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    1. Thanks for the comment! I've made the change.

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  3. When you cite only the genus name, I think it is not italicized. What do you do?

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    1. Chicago style italicizes the genus name when it's used on its own (see 8.119). For example "it belonged to the genus Smilodon."

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  4. What if I want to write the latin name in the title, JUNCUS INFLEXUS L. or JUNCUS INFLEXUS LINNAEUS? Because as far as i'm concern we are not allow to use abbreviation in title.

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    1. Yes, I think whether you abbreviate or spell out "Linnaeus" just depends on your publication's preferred style. I definitely see some people spelling out Linnaeus in titles, so you'll be in good company.

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  5. Thanks for your useful comments. I was looking for the rule that says when (in your reference list) you write the title of a book that includes the scientific name and the title is supposed to be in italics, then the scientific name is written in non-italic font, when all the other words are in italics. Can you confirm this?

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  6. I understand the 'spp.' does not have to be underlined. What about the genus before the 'spp.'? E.g. in Eimeria spp., do I have to underline the 'Eimeria' alone when writing or not?

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    1. Yes, you have to underline Eimeria.

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    2. Yes, as Ricardo says, when Eimeria appears alone or in "Eimeria spp.," it should be in italics. If you're underlining instead of using italics, then underline. (As a side note, I recommend using underlining only when you're not able to use italics, for example if you're writing by hand or using a typewriter.)

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  7. I hope you will keep sharing more interesting posts.

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  8. Hi Eva, Thanks for posting this article. I need some help: what does ¨f¨ mean in Columba livia f. domestica? Thanks!!!

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  9. I arrived here because as a proofreader for a large international publisher I was trying to determine how to correct a book title containing a scientific name: The Diverse Faces of Bacillus Cereus. Ultimately I decided that the title as displayed on an accompanying cover image of the book, where it appears as The Diverse Faces of Bacillus cereus (with "Bacillus cereus" italicized and the species name set in lowercase), was correct. Do you concur? Thanks for your help!

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    1. Yes, I think that's a good decision. Chicago's guideline is to lowercase the species name in a title-case headline, and it also suggests maintaining the italics in the title (setting them in roman type if the rest of the title is in italics, or italics if the rest of the title is roman).

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    2. Thanks, Eva! I appreciate your prompt response. (And I'm relieved I made the right decision!)

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  10. Would any one be able to explain to me exactly why some things have to be italicized?
    Is it for clarification?
    Cheers

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    1. Good question. I think the short answer is that it's a widely-used convention, so following it helps your reader understand your writing easily. But italicizing the scientific name fits in with the common style convention of italicizing foreign words, since the scientific name was traditionally in Latin.

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  11. Anybody recognize "Colegii Blosoromii Insula' Longa' "?
    It's the name of a college on a medical school diploma, possibly in Europe.

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  12. Nice informative post! Another question is: in the title of an article, when reporting both the common and scientific name, which format is better?

    ...common name (Genus species)
    vs.
    ...common name, Genus species
    vs.
    ...common name Genus species

    In the above, Genus species are italicized of course. I prefer to include both the common and scientific name so that the audience doesn't need to look it up if unfamiliar (e.g., red swamp crayfish, Procambarus clarkii) but which of the above presentations is best is quite unclear to me - perhaps it doesn't matter...

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    1. I prefer the parentheses, but I think the comma will probably also be reasonably clear. There's no rule or convention as far as I know.

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  13. When the genus name is used alone, i.e. "... several Brassica species...", should it be italicised? kthxbi

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    1. If you're using the genus name alone as a genus name then it should be italicized: "Brassica campestris and other species of Brassica." But if you feel that in the context, brassica is being used as a common name, then I would lowercase it and not use italics: "Many brassicas have yellow flowers."

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  14. I'm querying about thesis title which request to capitalize. Example, should it be ''EVOLUTION OF ESCHERICHIA COLI'' or ''EVOLUTION OF Escherichia coli''

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    1. If the style of the document requires the title to be in all capital letters, then I would put the genus and species in full caps, as in your first example.

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  15. how to properly write this:
    Cymbopogon citratus (DC.) Stapf

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  16. I am of the opinion that when scientific names are written in capitals, they should not be in italics.

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