Why do some scientific names have cf. in them?

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Lots of fishkeepers mistakenly think that cf. in a scientific name means "colour form" but it has a rather different meaning, as Matt Clarke explains.

The abbreviation cf. comes from the Latin word conferre, which means “compare to” or “confer.” It’s not short for colour form, as some mistakenly believe.

The use of cf. in a scientific name (for example Schistura cf. balteata - the loach pictured above) means that the person using the name is saying the fish should be compared to a given species, as it might not be exactly the same species.

It’s a way of applying a provisional name to a species and is most frequently used when new fish are discovered that look slightly different to the form normally encountered. It indicates that the fish might be a variant of the same species, but could also turn out to be something completely different.

Another term species affinis is also used to perform a similar role and is sometimes seen in scientific names using the abbreviation aff (or ‘sp. aff.’). For example, Danio sp. aff. rerio.

Both are examples of ‘open nomenclature.’ Another example of this is the use of a question mark, ie. Devario anomalus? (a Devario, but species uncertain) or Devario? anomalus? (to indicate both an uncertain genus and an uncertain species).

This item was first published in the October 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.