It doesn’t appear to be that this code is outdated, because it was last updated in 2025. In 2025, just like now, stateofmatter was called stateofmatter, not root, subkingdom didn’t exist (apart from in a few inactive taxa), and subterclass and complex existed.
I don’t understand how subterclass and complex are functional ranks when they’re not included here.
Also, why can’t we use stateofmatter, root, or subkingdom in observation search?
I have no actual idea - I’m not familiar with the underlying code. But these seem to be internal API / code names - and it’s not surprising that some of them are displayed differently or are just placeholders.
I expect that it was originally called root (for obvious reasons) but that didn’t make sense to display to end users. And there are some ranks that seem to be placeholders.
But a very good question about where subterclass and complex come from. Those seem to be 11 and 44 respectively. I suspect they’ve been added in later in another place, and this file has not been kept up to date.
I would prefer “root” honestly. I really do think it’s the best name for the rank. “stateofmatter” is nonsense. Everyone knows the states of matter are solid, liquid, gas and plasma.
“Complexes” are informal categories often used by biologists to include creatures that are closely related and very similar in some way. iNaturalist uses this category for groups of organisms that look so similar they’re very hard to identify to species from photos we see on iNaturalist. In order to fit this category into the existing taxonomic framework, iNaturalist requires that each complex also be a clade. This limitation is sometimes frustrating. For example, I wish that the “yellow-faced” bumblebees could be united in a complex but are not more closely related to reach other than they are to other, different-looking species. However, this limitation does is allow the complex to be slipped into the formal taxonomic framework without causing conflicts. Overall, I think iNaturalist’s use of complexes is useful.