Commonly Encountered Taxonomic and Systematic Abbreviations

There are no hard-and-fast rules about the use of "cf." and other abbreviations. However, the following usages are very widespread in biologic circles, and are required by some journals:

Etheostoma blennioides: The identification is certain.

Etheostoma cf. blennioides (or cf. E. blennioides): The identification is uncertain because the material is fragmentary or otherwise flawed.

Etheostoma aff. blennioides (or aff. E. blennioides): The material is good enough to identify, but may belong to an unnamed species related to M. blennioides.

Etheostoma blennioides?: Definitely Etheostoma, but may not be blennioides.

Etheostoma? blennioides: Definitely blennioides, but this species may not belong to Etheostoma (for instance, the taxonomy of this genus may need revision.)

?Etheostoma blennioides: Both genus and species are in doubt.


You will occasionally see other abbreviations, especially in the older and more technical literature. Schenk and others (1948, Procedure in Taxonomy, p. 27-29) list three pages of Latin words and abbreviations, including the following, which have modified slightly:

aff. = affinis = having affinity with but not identical with

auct. = auctorum = of authors [that is, of various authors]

cf. = confer = to be compared to

emend. = emendatio = emended

f. = forma = form

fide = trusting [the written word of]

gen. et sp. nov. = genus [novum] et species nova = new genus and species

ibid. = ibidem = the same [reference]

incertae sedis = of uncertain position

in litt. = in litteris = in correspondence

lapsus calami = a slip of the pen

loc. cit. = loco citato = [in the] place cited [to the page]

mihi = [belonging] to me (i.e., my new species)

nob. = nobis = [belonging] to us

nom. nov. = nomen novum = new name

nom. nud. = nomen nudum = nude name (new name given without an illustration or description)

non = not

nec = nor

non vidi = I have not seen [it]

non viso = not seen

nov. = novum = new

olim = formerly

op. cit. = opere citato = [in the] work cited

partim = part

passim = here and there

pro parte = in part

q. v. = quod vide = which see

s.l. = sensu lato = in a broad sense

s.s. = sensu stricto = in the strict sense

sic = thus; [this is] so (that is, exactly as shown)

sp. = species = species (singular)

spp. = species = species (plural)

sp. nov. = species nova = new species

subgen. = subgenus = subgenus

supra cit. = supra citato = cited above

teste = according to [the spoken word of]

vide = see


Schenk, Edward T., McMasters, John H., Keen, Myra A., and Muller, Siemon William, 1948, Procedure in taxonomy (2nd edition). Stanford, California, Stanford University Press, vii + 93 p.

Also, an exclamation point (!) is occasionally used to indicate that the author has seen a particular specimen, not just read about it.