I’m trying to make sense of how iNaturalist models taxa, as part of a broader attempt to look at how other databases and projects such as Wikidata model taxa and taxonomic names. I’m hoping for some clarification here - for some background see Taxonomic concepts continued: iNaturalist. (I asked this question on Twitter https://twitter.com/rdmpage/status/1295629542867054592 but was encouraged to ask it here instead)
In some databases every different taxonomic name gets an identifier, regardless of whether it refers to the same species for not. In other databases, the identifier for a taxon remains unchanged, even if the name changes. Most databases seem to be somewhere in between.
Originally I thought a /taxa/ URL in iNaturalist modelled a taxon, such as a species. For example, the “Thrush-like Schiffornis” Schiffornis turdina https://www.inaturalist.org/taxa/8793 has been split into five taxa, one of which bears the same scientific name ( Schiffornis turdina https://www.inaturalist.org/taxa/513975). Given that the composition of Schiffornis turdina has changed, there is an argument to be made that its taxon identifier should change, which is what iNaturalist does, so 8793 becomes 513975.
But then there are cases such as Heraclides rumiko 428606, which iNaturalist has moved to the genus Papilio, becoming Papilio rumiko, so 428606 becomes 509627. This suggests that the iNaturalist /taxa URLs don’t identify taxa, because Heraclides rumiko and Papilio rumiko are the same species (there’s some disagreement in the literature over whether Heraclides should be a separate genus to Papilio, but not that there is a species rumiko). Likewise, the transfer of the African piculet Sasia africana 18393 to Verreauxia africana 792894 doesn’t change anything about the African piculet, but simply reflects a proposal to have it in its own genus distinct from Sasia.
So, in summary, is there some place I can go to find out more about the rationale for how iNaturalist assigns identifiers (the number after /taxa/) to the taxa in its database? Specifically, why do these change when the taxonomic name changes?