A team of paleontologists at the Shenzhen Campus of Sun Yat-sen University, along with a researcher from the State Key Laboratory of Cellular Stress Biology, has made a remarkable discovery: the oldest known fossil record of larval neuropterans. This groundbreaking find, unearthed in the Daohugou Beds of Inner Mongolia, China, provides new insights into the evolutionary history of lacewings—an ancient group of insects that have existed for hundreds of millions of years.
Lacewings belong to the order Neuroptera and are characterized by their delicate, veined wings, which can reach impressive spans of up to 65 mm. Today, they are primarily found in North America and Europe, though fossil evidence suggests they were once widespread across Asia as well. Previously, the oldest known lacewing fossils were dated to approximately 165 million years ago, but this new discovery pushes the known history of these insects even further back in time.
The fossil was discovered by Bai Bingyang, an excavator at the dig site, and immediately caught the attention of researchers due to its exceptional preservation and unique features. Unlike modern lacewing larvae, which are typically small and inconspicuous, this fossilized specimen was remarkably large and had a distinctive long neck, making it stand out among previously identified neuropteran fossils.
The fossil was embedded in a layer of compressed tuffaceous siltstone, a sedimentary rock that forms in volcanic ash-rich environments. This indicates that the ancient lacewing lived in an ecosystem shaped by frequent volcanic activity, likely near a lake or river system. The presence of other ancient insect fossils in the same rock layer suggests that this was once a thriving habitat for various arthropods.
One of the most striking features of this newfound lacewing species is its elongated neck, which gives it a giraffe-like appearance. Measuring 41.2 millimeters in length, the neck would have provided a significant advantage in hunting. Unlike modern lacewing larvae, which actively roam in search of prey, this ancient species may have adopted an ambush strategy—concealing itself behind tall plants or other natural cover while using its long neck to spot and strike unsuspecting prey.
The researchers also examined the fossilized stylets, which are sharp, protruding mouthparts used by lacewing larvae to stab and inject digestive enzymes into their prey. The stylets in this specimen were positioned at the tip of its elongated neck, further reinforcing the idea that this species was an efficient predator. This adaptation likely allowed it to capture a wider range of prey than its modern relatives, making it a formidable hunter in its ancient ecosystem.
Today’s lacewing larvae typically inhabit moist environments, such as leaf litter near mountain streams, and spend their early stages of life underwater. However, analysis of this fossil suggests that Palaeoneurorthus baii, as the species has been named, may have lived at the bottom of a shallow lake. This hints at a potentially aquatic or semi-aquatic lifestyle, differing from the purely terrestrial habits of most modern lacewings.
The discovery of Palaeoneurorthus baii is more than just an exciting addition to the fossil record—it provides crucial evidence about the evolutionary adaptations that helped ancient neuropterans survive in diverse environments. The presence of an elongated neck and specialized hunting mechanisms suggests that these insects developed unique traits in response to specific ecological pressures, shedding light on how they thrived during the Jurassic period.
This find also underscores the importance of the Daohugou Beds as one of the world’s most significant fossil sites. Known for its exceptionally well-preserved fossils, this region has yielded a treasure trove of ancient life, including dinosaurs, early mammals, and diverse insect species. Each new discovery from this site adds another piece to the puzzle of prehistoric ecosystems, helping scientists reconstruct the complex web of life that existed over 165 million years ago.
The researchers involved in this study emphasize that this discovery challenges previous assumptions about the evolutionary history of lacewings. It suggests that ancient neuropterans were far more diverse in form and behavior than previously thought. While modern lacewings have evolved into relatively uniform shapes and behaviors, their ancestors appear to have experimented with a wide range of body structures and hunting techniques.
Further studies will be required to fully understand the evolutionary implications of Palaeoneurorthus baii. Paleontologists plan to continue excavations in the Daohugou Beds to search for additional fossils that might provide even more context for the evolutionary journey of lacewings and other ancient insects.
This discovery is a reminder of the vast and largely unexplored history of insect evolution. While dinosaurs and large prehistoric mammals often dominate popular discussions of paleontology, insects like lacewings have played an equally crucial role in shaping Earth’s ecosystems for hundreds of millions of years. Each fossilized insect tells a story of adaptation, survival, and change—stories that scientists are only beginning to piece together.
More information: Xuheng Du et al, Giant Jurassic dragon lacewing larvae with lacustrine palaeoecology represent the oldest fossil record of larval neuropterans, Proceedings of the Royal Society B: Biological Sciences (2023). DOI: 10.1098/rspb.2022.2500