Lichens are symbioses of fungi and algae (and/or cyanobacteria) that play important ecological roles and colonize many substrates, including fossils. They may serve as biological indicators of fossils in western North America and could be identified using remote sensing, according to new research.
Predominant colonization of dinosaur bones by lichens. Image credit: pickles etc.., doi: 10.1016/j.cub.2025.09.036.
“This study shows how modern organisms can help us find ancient ones,” said Dr Brian Pickles, a researcher at the University of Reading.
“What's remarkable is that these lichens, essentially miniature ecosystems, are based on the remains of dinosaurs that died more than 75 million years ago.”
“Using drones to detect spectral signatures of lichens has the potential to revolutionize the way paleontologists search for fossils.”
During the study, Dr. Pickles and his colleagues discovered that two types of lichens – Rusavskia Elegance And Xanthomendosis trachyphylla – colonized up to 50% of exposed fossil bones, but less than 1% of surrounding rock fragments.
This is likely because dinosaur bones provide the alkaline, calcareous, and porous substrate that lichens prefer.
“This pattern of lichen growth predominantly on fossil bones has been noted for decades but has not been quantified until now,” said Dr Caleb Brown, a researcher at the Royal Tyrrell Museum of Paleontology.
“When first encountering high concentrations of exposed fossil bones, such as bone beds, what is often noticed first is the 'meadow' of orange lichen rather than the bones themselves.”
Using drones with specialized sensors, the authors identified lichen-colonized fossils in aerial photographs with a pixel resolution of 2.5 cm.
Lichens have distinct spectral properties: lower reflectivity in blue wavelengths and higher reflectivity in infrared bands.
This method can provide significant benefits for paleontological exploration, especially in remote areas where traditional ground-based surveys are difficult.
This approach could speed up fossil discovery while reducing mine costs and environmental impacts.
The study is based on decades of informal observations by paleontologists.
In 1980, paleontologist Darren H. Tanke proposed that the orange pigmentation of lichens on Centrosaurus the bones could be discovered by satellites, a prediction that seems closer than ever now that they can be found using airborne drone technology.
“This drone survey lays the groundwork for mapping much larger areas using aircraft and satellites,” said Dr. Derek Peddle, a researcher at the University of Lethbridge.
“The new lichen indicators we have developed will help us find fossils across vast landscapes.”
“It’s exciting to combine our imaging technology with the expertise of this international team to advance dinosaur discovery through lichen remote sensing.”
teams paper was published this week in the magazine Current biology.
_____
Brian J. Pickles etc.. 2025. Drone remote sensing of lichens to detect dinosaur bones. Current biology 35 (21): P1044-P1045; doi: 10.1016/j.cub.2025.09.036
