Known only as a name

605 of the 21,572 species here have a name, a family, and nothing else. Nobody has measured one, weighed one, recorded what it eats, photographed one under a licence anyone may reuse, or assessed it for the Red List.

They are not missing because this encyclopedia failed to look. Every free machine-readable source was asked for every one of them. They are missing because the work has not been done. A reference that quietly dropped them would look more complete and be less true.

Each of these still has an entry, because a species is not deleted for being obscure. The entry says what is known, which is its name and where it sits, and says plainly that the rest has not been recorded. See how to read an entry.