Scientists Describe More Than 16,000 New Species a Year — and the Pace Keeps Accelerating
The age of species discovery is not winding down. A sweeping new analysis of roughly 2 million species’ taxonomic histories found that researchers are documenting new species faster than ever before, with more than 16,000 added each year between 2015 and 2020. The findings, and the staggering projections that accompany them, offer a data-rich foundation for anyone teaching or working in the life sciences.
The study, published in Science Advances and led by John Wiens, a professor in the University of Arizona Department of Ecology and Evolutionary Biology, tracked discovery trends across all major groups of living organisms — animals, plants, fungi, and beyond.
“Some scientists have suggested that the pace of new species descriptions has slowed down and that this indicates that we are running out of new species to discover, but our results show the opposite. In fact, we’re finding new species at a faster rate than ever before,” Wiens said.
How the Study Worked
The research team analyzed the taxonomic histories of approximately 2 million species spanning all major groups of living organisms. Rather than focusing on a single taxon or geographic region, they examined discovery trends across the full spectrum of known life.
Their analysis covered both the cumulative count of described species and the rate at which new descriptions are being published. That dual approach allowed them to project how much biodiversity likely remains undocumented.
Annual Discovery Rates, Broken Down
Between 2015 and 2020, the annual average of more than 16,000 new species included over 10,000 animals per year (dominated by arthropods and insects), 2,500 plants per year, and 2,000 fungi per year.
These are not marginal organisms slipping through classification cracks. As Wiens put it: “These thousands of newly found species each year are not just microscopic organisms, but include insects, plants, fungi and even hundreds of new vertebrates.”
Hundreds of new vertebrates annually. That single data point directly counters the intuition many biology students and working scientists hold that vertebrate taxonomy is essentially finished.
The Projected Gap Between Known and Unknown
The distance between currently described species and the study’s projections for total species richness is enormous.
Fish offer a clear example: approximately 42,000 species are currently described, but the study projects there may be as many as 115,000 fish species. For amphibians, roughly 9,000 species are described against a projected total of 41,000. The researchers suggested the final number of plant species could exceed half a million. And scientists have identified around 1.1 million insect species, though estimates suggest the true number could be up to 6 million or even 20 million, according to Wiens.
Wiens stated plainly: “Right now, we know of about 2.5 million species, but the true number may be in the tens or hundreds of millions or even the low billions.”
For anyone teaching biodiversity metrics or conservation biology, the implication is hard to overstate: the vast majority of Earth’s species remain scientifically unknown.
Molecular Tools and the Discovery Curve Ahead
The study also looked forward. Most new species are still identified by visible traits, Wiens noted. Morphological analysis has driven taxonomy for centuries, but it has inherent limitations, particularly with cryptic species — organisms that appear identical to known species but are genetically distinct.
“But as molecular tools improve, we will uncover even more cryptic species – organisms distinguishable only on a genetic level. This is especially promising for revealing more unique bacteria and fungi,” Wiens added.
The integration of DNA barcoding, whole-genome sequencing, and phylogenomic analysis into taxonomic practice is expanding the known tree of life, not merely refining it. The study’s projections account for this trajectory and suggest the discovery curve has not yet begun to plateau. For professionals and instructors working in genetics, microbiology, or bioinformatics, this dimension of the research carries particular weight.
What Comes Next
The research team plans to map geographic hotspots for undiscovered species and examine who is making these discoveries, according to the study. Those questions carry implications for how funding, fieldwork, and institutional support are distributed across the scientific community.
Wiens offered a parting frame for the work’s scope: “Even though Linnaeus’ quest to identify species began 300 years ago, 15% of all known species have been discovered in just the past 20 years. So much remains unknown, and each new discovery brings us closer to understanding and protecting the incredible biodiversity of life on our planet.”
Production of this article included the use of AI. It was reviewed and edited by a team of content specialists.
This story was originally published March 6, 2026 at 2:49 PM.
