Photomicrograph of Basiceros enana, a newly discovered extinct dirt ant species preserved in Dominican amber, formed from tree resin that fossilized millions of years ago. (Image Credit: Gianpiero Fiorentino (NJIT))NewsletterSign up for our email newsletter for the latest science newsA golden opportunity in the Caribbean has led to the discovery of an extinct “dirt ant” that has been confined within a piece of amber for 16 million years. Dirt ants (Basiceros) are true experts of camouflage that can blend in with the ground, and now, a fossilized member of the group is shedding light on their complex evolutionary history. A recent study published in the Proceedings of the Royal Society B describes the species as Basiceros enana and its link to modern dirt ants. Although the species disappeared sometime during the Miocene epoch (23 million years to 5.3 million years ago), the new fossil specimen could still provide insight into solving local extinction issues that have become increasingly relevant in the modern age.Preserved in Amber Modern dirt ants — able to hide in dirt using particle-binding hairs on their bodies — inhabit rainforests ranging from Costa Rica to southern Brazil. The realization that one extinct ant species in the genus used to live in the Caribbean has brought a fresh heap of questions for researchers to answer.The researchers found the adult B. enana specimen preserved in 16-million-year-old amber from the Dominican Republic, which was essentially tantamount to finding buried treasure.“Dirt ants are rare finds in the wild. Finding one today is exciting given how well they stay hidden, but captured in amber, it's like finding a diamond,” said corresponding author Gianpiero Fiorentino, a Ph.D. candidate at the New Jersey Institute of Technology, in a statement. “This fossil is singularly distinct from all its modern relatives and reshapes the evolutionary history of Basiceros.”The researchers say that the existence of Basiceros on the islands may have been enabled by ancient land bridges that dirt ants could have used to travel from the mainland to the Caribbean. Visualizing the Caribbean Dirt AntTo inspect the fossil in more detail, the researchers turned to advanced imaging and 3D reconstruction techniques. Since the ant was protected inside the amber, its physical characteristics could be gleaned in great detail. The researchers then compared it with all of the known modern dirt ant species and traced its evolutionary lineage through molecular dating analyses. One of the major differences between B.enana and modern dirt ants is their size. B. enana is much smaller, measuring only 5.13 millimeters in length, while modern dirt ants can reach nearly 9 millimeters in length. Scientists previously assumed that all dirt ants were once much larger and had shrunk over time, but the study upends this notion, suggesting that the ants nearly doubled in size over the span of 20 million years.Despite the contrast in size, B. enana displays some familiar dirt ant traits. It likely had the same ability to become nearly invisible to predators and prey (called crypsis). It would have accomplished this feat with the help of long “brush hairs” and shorter “holding hairs” that could adhere soil and leaf litter particles to its exoskeleton. “What this shows is that playing dead and hiding pays off,” said Fiorentino in a statement. “Uncovering a unique fossil like this helps us understand how long organisms may have been employing this strategy, though the presence of these characteristics does not necessarily guarantee they behaved in this way.”A Blueprint for BiodiversityThe camouflaging prowess of these ants couldn’t save them from severe ecological changes during the Miocene, however. “Their extinction could have come down to a loss of available niches or interspecific competition. These ants are predators, and an overall trend that we see from the Caribbean is a loss of predator ant diversity,” said Fiorentino in a statement. “Over a third of ant genera have gone extinct on the island of modern-day Dominican Republic since the formation of Dominican amber."The researchers say that B. enana could provide a framework for understanding how local extinction should be addressed in the future, as biodiversity continues to suffer in neotropical environments like the Caribbean. Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article: Proceedings of the Royal Society B. Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.1 free article leftWant More? Get unlimited access for as low as $1.99/monthSubscribeAlready a subscriber?Register or Log In1 free articleSubscribeWant more?Keep reading for as low as $1.99!SubscribeAlready a subscriber?Register or Log In