You might sometimes encounter various confusing GBIF keys when using GBIF or rgbif,
All GBIF taxonomic keys are id numbers used in place of words to identify species or some other taxonomic group.
A taxonKey is the primary id number used in GBIF to id a species (or some higher group). These are the id numbers found in the GBIF backbone taxonomy. Often you will see them in the URL of an occurrence search: https://www.gbif.org/occurrence/search?taxon_key=7412043. These are the most important keys and usually what other keys map back to (rule of thumb: “all keys lead to taxonKeys”).
Using rgbif or GBIF API, you might encounter a usageKey. This key can be treated as equivalent to a GBIF taxonkey in the context of the GBIF Backbone. I have never found a usageKey in the wild that was not equivalent to a GBIF taxonKey, but it might exist.
Sometimes you might find a speciesKey in a download or somewhere else. This key is the key for the species and is often equivalent to the GBIF taxonKey in the context of the GBIF Backbone. If the record is not of rank SPECIES, it won’t have a speciesKey. The same goes for the other GBIF ranked keys: genusKey, familyKey, classKey, orderKey, phylumKey, kingdomKey. These are also equivalent to their corresponding GBIF taxonKeys when the taxa is that rank.
A nubKey is a GBIF taxonKey found in the context of another checklist. For example, the checklist WORMS has 154946057 as its key for Animalia, but a nubKey of 1, which is the GBIF taxonKey for Animaila. It is called a “nubKey” rather than a taxonKey for legacy and compatibility reasons.
parentKey: in the context of the GBIF backbone the parentKey, is the GBIF taxonKey of the nearest higher rank (genus, family, order, class ect…). For example, the parentKey of Arthropoda (54) is Animaila (1). However, in a checklist that is not the GBIF backbone these numbers will be different.
Let me know if you have encountered any other keys that you find confusing…