Taxonomies
Biological taxonomy is not fixed, and opinions about the correct status of taxa at all levels, and their correct placement, are constantly revised as a result of new research, and many aspects of classification will always remain a matter of judgement. The ITIS database is updated to take account of new research as it becomes available, and the information it yields is likely to represent a fair consensus of modern taxonomic opinion. Inevitably, however its information cannot be final, and is likely to be more reliable for some groups than others.
So says Wikipedia, in discussing ITIS, the Integrated Taxonomic Integrated System. Who knew that the USDA was in charge of calling us homo sapiens?