sentences:  There are an estimated 14M mainly unpublished species, however this number is not certain as there is a lack of data on the possible number of undescribed insect, nematode, bacteria, fungus and many other species.In 2015, an expert panel presented a consensus hierarchical classification of life, including some sectors not yet represented in the published "Catalogue".In the same year, the Catalogue of Life, Barcode of Life Data System, Biodiversity Heritage Library, Encyclopedia of Life, and the Global Biodiversity Information Facility met to consider building a single shared authoritative nomenclature and taxonomic foundation "Catalogue of Life Plus" that could be used to order and connect biodiversity data, including content not yet in CoL but available via other sources, to serve both the users of the present "Catalogue" and users of extended taxonomic content (such as GBIF) using a common infrastructure.