The taxonomic backbone in SCAN is from ITIS. There are a number of people that have taxonomic editing rights and have added to certain groups. The only two significant additions have been North American Lepidoptera from Greg Pohl et al 2016 and the World Spider Catalog.
For an example on how best to provide SCAN with the capacity to update taxonomy tables, below is the original file Greg Pohl provided for North American Lepidoptera and the ensuing csv file created from Greg’s file to upload and update the Lepidoptera taxonomy.
Original Pohl et al., 2016 Excel file
SCAN format for updating taxonomy table
Pohl, G.R., Patterson, B. and Pelham, J.P., 2016. Annotated taxonomic checklist of the Lepidoptera of North America, North of Mexico. Working paper published online by the authors.