Taxon Version key relates to a taxonomic concept so this is the most important key. A Taxon Version Key can be used in many lists so can be used by mutiple Taxon List item keys. The NBN Atlas and most other system use just the Taxon Version key.
The Taxon key is a bit meaningless as it just links to a name and on its own tells you nothing.
All Taxon Version keys have a Recommended Taxon Version key. The Nameserver tables holds the Taxon Version Key and the Recommended Taxon Version key. If the Recommended TVK is not the same as the Taxon Version key in Nameserver then the Taxon Version key represents a junior synonym. This is how the UKSI manages name changes, splits etc. with Nameserver linking older taxonomic concepts with the latest ones. There is also the Organism table which hold the just the Recommended Taxon Version keys arranged in a hierarchy.
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