Single ant species unmasked as 26+ distinct species: Australian savannas may harbor world's richest ant fauna
image: The ant Melophorus dicyrtos from Australia's monsoonal (seasonal) tropics represents dozens of species. It is further documentation of undescribed ant hyperdiversity in the region, which appears to harbour the world's richest ant fauna.
Credit: Alan N. Andersen, François Brassard, and Benjamin D. Hoffmann.
Date: May 16, 2026
Darwin, Australia: For decades, the Amazon basin has been universally regarded as the global epicenter of ant diversity, with an estimated 2,000 species. However, new research published in Biological Diversity upends this paradigm by demonstrating that Australia’s vast tropical savannas harbor vastly more ant species than previously recognized. The study focuses on Melophorus dicyrtos, a common ant species described in 2017 and thought to occur widely across northern Australia.
Using an integrated approach combining mitochondrial CO1 DNA barcoding, detailed morphological analysis, and geographic distribution data, the research team analyzed 74 specimens collected from across the Australian monsoonal tropics. They identified 26 distinct species within what was previously considered a single taxon, with both Poisson Tree Processes (PTP) and Bayesian PTP (bPTP) statistical analyses supporting these delimitations. The species are grouped into nine major genetic clades, each exhibiting unique morphological characteristics, particularly in mesosomal (thorax) structure.
The researchers found that species diversity is heavily concentrated in higher rainfall regions, with 13 species recorded in the Northern Territory’s Top End alone and six in far North Queensland. Remarkably, eight species co-occur in just the Kakadu and Nitmiluk National Parks region, with four species endemic to Nitmiluk National Park. Based on sampling coverage and high species turnover rates across the landscape, the team estimates that the total size of the M. dicyrtos complex exceeds 50 species.
This finding is not an isolated case. Previous studies by the same team have shown that several other widespread Australian ant “species” are actually complexes containing dozens or even hundreds of cryptic species. Collectively, these results indicate that the total ant fauna of monsoonal Australia is at least twice, and likely several times, the previous estimate of 1,500 species. This would make it the most species-rich ant fauna on Earth, surpassing even the Amazon basin.
“Our findings highlight a profound underestimation of global insect diversity, particularly in understudied savanna ecosystems,” said lead author Professor Alan Andersen of Charles Darwin University. “Monsoonal Australia’s ant diversity has been overlooked simply because most species remain undescribed. This has major implications for biodiversity conservation and our understanding of global biogeographic patterns.”
The study underscores the critical need for comprehensive taxonomic work using modern integrative approaches to uncover the true extent of Earth’s biodiversity, especially in regions facing increasing threats from climate change and habitat loss.
Original Source
Andersen, Alan N., François Brassard, and Benjamin D. Hoffmann. 2025. “Unrecognised Ant Megadiversity in the Australian Monsoonal Tropics: The Melophorus dicyrtos Heterick, Castalanelli and Shattuck Complex.” Biological Diversity 2(1) : 44–53.
https://onlinelibrary.wiley.com/doi/10.1002/bod2.70003
Keywords
ant diversity, CO1, species complex, species delineation, species richness, unrecognised diversity
About the Author
Alan N. Andersen (First author), professor at Charles Darwin University, former Chief Research Scientist and Officer-in-Charge of CSIRO’s Tropical Ecosystems Research Centre (1995-2016). His research focuses on global ant community ecology, ants as bioindicators, tropical savanna ecology, and fire ecology and management.
François Brassard (First author and corresponding author), Research Associate at Charles Darwin University, Australia. His main research interests include ant ecology, evolution, biogeography, photography, and taxonomy. He has published over 20 peer-reviewed academic papers with a total of 287 citations.
Benjamin D. Hoffmann (First author and corresponding author), Research Scientist at Charles Darwin University and CSIRO Darwin Laboratory, Australia. His research focuses on the biology, ecology, impacts and management of invasive ants. He has published over 90 peer-reviewed academic papers, with an h-index of 36 and a total of 4918 citations.
About the Journal
Biological Diversity (ISSN: 2994-4139) is a new open-access, high-impact, English-language journal, devoted to advancing biodiversity conservation, enhancing ecosystem services, and promoting the sustainable use of resources under global change. It features innovative research addressing the global biodiversity crisis.