How do people keep track of undescribed species?

If a species is known to exist but has no formal name/description, then what happens in the meantime? How do people like researchers navigate discussion of the species when it has no name? Are they given placeholder names? Who decides those? Is there a list of them somewhere?


At least for insects in North America, unnamed taxa often get a temporary placeholding name like “Sparklius n. sp. 1”. You’ll find these on such sites as BugGuide and Moth Photographers Group. However, within the iNaturalist taxonomic framework, there seems to be no way to add undescribed species with such ad hoc names. iNat can’t/won’t incorporate them. Such observations on iNat necessarily reside in the lowest available taxon (e.g. genus, species group, or section). To keep track of such observations on iNaturalist, what I’ve done on an interim basis is to add an Observation Field such as “Species Identification” to an observation (which is for the time being stuck at genus level) and use the temporary species name in that field (e.g. Sparklius n. sp. 1 on BugGuide). The latter should not be made up, but rather should fall in line with whatever temporary names are being used by authorities on those other platforms. Such observations thus become searchable/findable via that Observation Field while they await formal description.


If they are recognized in the literature, they are usually given a number or letter, such as Monadenia new sp. A or Helminthoglypta new sp. 3. Other times they are just referenced by common names, such as the Palomar Mt banana slug. Ideally these would be described, but researchers typically wait until they can thoroughly investigate the phylogeny and the literature before applying names. Often you will see these “placeholder” names referenced in later papers:

You can see how many “undescribed” species ended up getting lumped under this one name.

Whether or not there is a list of these depends on the group. If there is a checklist of known species, they usually include known undescribed species in my experience.


I see! I stumbled upon an observation earlier of a species that some in the comments have termed Pheidole epem121, which sent me down a rabbit hole in which I stumbled upon a list of taxa with designations I’m not quite used to seeing, ex. Pheidole cf. parva ZB42639 and Pheidole sp. JS130521_55. Are these also undescribed? What’s the significance of the numbers/letters chosen for each?


In Australia, for plants, we have a system called ‘phrase names’. This allows putative new species to be assigned formal, standardised names. An example is Leucopogon sp. Torrington (L.M.Copeland 3720). The name is usually constructed as:

[Genus] + [sp.] + [descriptive name] (this is usually either the ‘type’ location or a notable morphological feature) + [collector name] + [specimen number]

You can also have phrase name subspecies of described species, eg Acacia terminalis subsp. Long inflorescences (P.G.Kodela 307)

This is a useful system as the names are largely consistent (there’s a bit of variation with how some are constructed), but also because under Australian conservation legislation, even though these taxa aren’t described yet, assigning them a phrase name means they can be formally assigned a conservation status and afforded full protection if threatened. A lot of phrase name species, particularly in Western Australia, are only known from a very small range, eg a single mine site, so giving them a phrase name is great for conservation protection in the interim while we figure out if they are actually are a new species (or a subspecies, or just variation of an existing species).

On iNat, I made an observation field and project to keep track of these:


You might have to ask ant people about those, but morphotaxon looks to be a taxon based only on morphology, which may or may not be related to evolutionary history, DNA, biogeography, etc. They therefore may not be valid names, and should probably be avoided in our system.

cf means confer, in this case used to mean “maybe this species, but not sure”. The numbers are probably associated with DNA sequences/samples and may or may not have taxonomic significance. There’s a lot of questionable (and even incorrect) stuff on GenBank so you have to take everything there with a grain of salt.


Oh this was very helpful, thank you! :) I hadn’t considered specimen number being included. I’ll definitely be checking out that project as well!

Thank you! :)

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cf from Latin
Used as an abbreviation for compare


It varies by taxon. For instance, in the loricariid (armoured catfish) world, previously ndescribed species are given L-numbers.

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Following on from @thebeachcomber you can see an Abstract of a paper we wrote where we attempting to get an international Standard on this - still a long way to go.

Chapman AD, Mesaglio, T & Taseski G. (2022). Formulaic Unpublished Names: The need for a TDWG standard and for the inclusion of such names in apps such as iNaturalist. Biodiversity Science Information and Standards 6: e91062.


For anyone who didn’t know this, “sp.” following the name of a genus means the species name is unknown to the writer.

Sp. can be used for an unidentified species, I believe, and is also used when you do not know enough to identify something to species level.

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That is correct. And if you know that you are referring to more than one species, the plural is spp.

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I thought that meant subspecies, like if someone identifies a leopard as Panther pardus ssp. pardus

As you correctly typed, the abbreviation for subspecies is ssp., but Jason typed spp., not ssp.


@lynnharper is correct; they are different abbreviations.
ssp = subspecies
spp = plural unknown species


« ssp. » in zoology only (ICNZ).
For algae, fungi and plant (ICN), and also prokaryotes (ICNP), it is « subsp. ».

This one is more often used as a general “compare” scenario, in the sense that it’s in that genus and resembles a most likely species, but the ID may not be confirmed. It is uncommon in my experience to see it used to indicate a known undescribed species (in those cases, I see aff. more often, “affinity”, implying relation but likely distinction taxonomically).

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Here we often use ssp. as we do var. (three letter abbreviation), for botany, and otherwise zoology. I have only infrequently seen it spelled as “subsp.” even internationally, I wonder why ICN has gone this route.

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