"The Catalogue of Life (CoL) is the nearest thing to a comprehensive catalogue of all known species of organisms on Earth. Continuous progress is made towards completion, and this edition contains 1,639,016 living and 5,763 extinct species. Please note that this is probably just over three quarters of the world's known species. This means that for many groups it continues to be deficient, and users will notice that many species are still missing from the Catalogue.
The present Catalogue is compiled with sectors provided by 157 taxonomic databases from around the world. Many of these contain taxonomic data and opinions from extensive networks of specialists, so that the complete work contains contributions from more than 3,000 specialists from throughout the taxonomic profession. Species 2000 and ITIS teams peer review databases, select appropriate sectors and integrate the sectors into a single coherent catalogue with a single hierarchical classification."
1,639,016 living and 5,763 extinct species (2016-10).