Biodiversity databases store taxonomic information alone or more commonly also other information like distribution (spatial) data and ecological data, which provide information on the biodiversity of a particular area or group of living organisms.
Species-focused databases contain information summarised at the species-level.
Some species-focused databases attempt to compile comprehensive data about particular species (FishBase), while others focus on particular species attributes, such as checklists of species in a given area (FEOW) or the conservation status of species (CITES or IUCN Red List).
Nomenclators act as summaries of taxonomic revisions and set a key between specimen-focused and species-focused databases.
They do this because taxonomic revisions use specimen data to determine species limits.