This is what I could find so far. Is there any such databases I am missing? Additionally, where can I find up to date (valid, extant) species numbers for taxa that may not have dedicated databases such as many insect and mite taxa?
Iāve got a layout of the resources i use for iNat curation (etc) of arthropods here on my wiki userpage. Itās biased to the terrestrial, hence the diverse Crustacea for example are essentially none. I was only recently beginning to build for the āmitesā etc which still seem mostly published checklists rather than online
See https://en.wikipedia.org/wiki/User:Sjl197
There you can see several other websites that use same underlying architecture (e.g. āWorld of Copepods Databaseā and āDecaNetā for biggies in the Crustacea) then updated into WoRMs, and then Catalog of Life [which should then be influencing GBIF etc]. Else also as said WoRMs includes many with freshwater and terrestrial lineages such as Isopoda - just have to often be careful with their setup filters - thereās a toggle option to only display āmarine onlyā taxa, which i think is the default.
Anyway, as many Crustaean are well done on WoRMs (from itās sources, and then integrate data well out from that into other online initiatves), thatās why iād not broken down detail of sources for Crustacea on my own wiki page. The crustacean lineage that i remain wary about via WoRMs and other sources are the Diplostraca (or wider Cladocera) which about a year ago i saw really messy conflicting implementation through WoRMS, but i now see link above for Cladocera says āunder constructionā. Else Itās only a small number of taxa in the grand scheme (about 1500 spp), just beware.
For the mites (etc) the WoRMs database has a few, but i think not updated in an age. For several lineages, i look to updates on ITIS, which then feeds into Catalog of Life. [See especially on the summary page of updates at https://www.itis.gov/whatsnew.html]
One addition for the āmitesā is if interested in good sources for the Parasitiformes - i recently did some curatorial update for iNat scheme with Argasidae. I actually found that what was on english wikipedia was actually far more consistent with all the recent literature than any of the supposed āchecklistsā etc on any of the supposed bigger ātaxon aggregatorā websites (e.g. CoL, GBIF etc), and the wikipedia efforts where mostly down to one user! I just made a few additional updates and tweeks [See https://en.wikipedia.org/wiki/Argasidae] The same user had built in the same for Ixodidae [https://en.wikipedia.org/wiki/Ixodidae], although i havenāt looked into iNat updates for those. Absolutely crazy that for one of the few arthropod lineages where thereās likely millions of $$$ are spent annually across the globe on agroecology, disease management etc and human heath that the most current (and complete) checklist seems to be by a single user on wikipedia!
Excuse the double reply, but World Odonata List and Odonata Central seem to use slightly different taxonomies, with the latter recognizing Protoneuridae while the former does not. Which is better used?