For the first time, scientists have discovered the head of a 6.5-foot-long arthropod after centuries of finding only incomplete fossils. Live Science
The face of Arthropleura, a car-sized, millipede-like creature, has finally been revealed through two well-preserved fossils, offering a clearer understanding of the largest arthropod to have ever lived. This enormous creature existed between 346 million and 290 million years ago during the late Paleozoic era, thriving in the warm, oxygen-rich atmosphere near the equator. With its ability to grow up to 8.5 feet long and weigh over 100 pounds, Arthropleura has fascinated scientists for centuries.
Despite being known to paleontologists since the 18th century, a major piece of the puzzle was missing—the head. Without a complete skull, it was challenging for scientists to fully understand Arthropleura’s evolutionary placement and its connections to modern-day arthropods like millipedes and centipedes. The recent discovery of the head, with visible features such as mandibles and eyes, has helped researchers finally unlock some of these mysteries. As paleontologist Mickaël Lheritier from a French university stated, this discovery offers key insights into where this giant creature fits in the evolutionary timeline.
Arthropleura’s body had long perplexed scientists. While it shared characteristics with modern millipedes, there were enough differences to fuel debates about whether it was more closely related to millipedes or centipedes. These two groups, though similar in appearance, diverged from each other about 440 million years ago—well before Arthropleura emerged. Paleontologists were unsure of Arthropleura’s exact position in the evolutionary tree until the recent discovery of its fossilized head.
The blue-colored stalked eyes of Arthropleura hint that its young may have lived in water before growing into land-dwelling adults. Live Science
James Lamsdell, a paleontologist not directly involved in the study, acknowledged that this new discovery appears to resolve the ongoing debate. The fossilized head provides strong evidence that Arthropleura belongs to the millipede family, though it still possesses some puzzling features. The fossils, discovered in France, were analyzed using CT scans, which revealed details like stalked eyes, curved antennae, and small mandibles—features that combine traits seen in both millipedes and centipedes.
The stalked eyes, in particular, have raised new questions about Arthropleura’s lifestyle and environment. Stalked eyes are typically found in aquatic animals such as crustaceans, rather than terrestrial ones like millipedes or centipedes. This suggests that juvenile Arthropleura may have lived in water before transitioning to a fully terrestrial life as adults. However, this theory is still up for debate, as Lheritier noted that the presence of stalked eyes in such a creature remains a mystery. It is possible that as Arthropleura grew older, it lost its stalked eyes as it adapted to living on land.
Although some questions remain about Arthropleura’s life stages and aquatic habits, scientists have now largely placed it within the millipede family. This discovery sheds new light on how this massive creature lived and evolved millions of years ago, and it marks a major step in understanding the evolutionary history of arthropods.
