How many new fungal species are described each year

The mean of about 3,900 new species a year comes from more than 7,800 names published across 2024–2025. It is the rate of scientific description, not the rate at which species come into being. Most organisms described existed earlier but had not been collected, recognised as distinct or formally named. The panel has high confidence in the sourced two-year total and calculated mean, but it does not pretend to know a separate result for each year.

The annual result also depends on how the counting is done. Databases record new names, new combinations and other nomenclatural acts, but only some of them are descriptions of a new species. A later revision may merge two names or split an old taxon. Simply subtracting the state of the database on two days therefore does not give a clean number of discoveries without checking the kind of each record.

Growth is driven by studies of the tropics, of microscopic groups and of environmental DNA, but a formal description requires more than a sequence alone. A diagnosis is needed, a comparison with relatives, designation of type material and publication in accordance with the rules of nomenclature. The bottleneck is often not the taking of a sample but the time of experts able to work up a given group, and access to comparative material.

Extrapolation illustrates the problem but is not a calendar forecast. At a mean of 3,900 names a year, moving from about 155,000 named species to half of the 2.5-million working estimate would still take close to 280 years if the rate and definitions stayed constant. In practice methods, funding and automation will change, as will the estimated total itself. The statistic should therefore be read as a measure of scientific throughput, not a completion date for the catalogue.

A two-year result, not two annual measurements

Kew reported in 2026 that more than 7,800 fungal species were named across 2024 and 2025. Dividing that total by two gives a mean of about 3,900 per year; it does not state that exactly this many were described in either individual year. For comparison, the 2023 report used a baseline of about 2,500 names per year.

The name count does not measure field expeditions alone. It also includes the splitting of species complexes, revisions of collections and lineages detected through molecular data. The current pace cannot safely be projected unchanged for centuries or treated as a completion date for the fungal catalogue.

Three figures, three contexts

About 2,000 a year was an older, broadly rounded editorial shorthand. Kew’s 2023 report gave about 2,500, while its 2026 release reported more than 7,800 across the preceding two years. The current panel shows only the mean derived from the latest of those values: about 3,900 per year.