It is worth mentioning that in mycology the term ‘species complex’ has a long tradition and is being used in the literature with increasing frequency. It is very useful. This isn’t a zoology-only issue. Sequence data often show that what we thought were single widely distributed species are actually multiple related cryptic species. Sometimes the related species are allopatric and sometimes sympatric. Sometime members of a complex can be macroscopically identical (and sometimes even microscopically identical), whilst others easily separated.
On iNat there are vast numbers of macro-fungal observations incorrectly assigned at species level where we know that complexes are involved. It is very hard to shift observer’s from their ‘pre-molecular’ concepts and names used in guide books. The species complex provides a painless way of injecting a bit more scientific rigor. Although correcting the identifications can be an uphill struggle against the CV.
In iNat the term Species Complex has a specific definition in the curator’s guide.
https://www.inaturalist.org/pages/curator+guide#complexes
Allopatry is not part of that definition.