Nine-Foot-Long Millipede

A long, long time ago, millipedes were nine-foot-long. Weighing in at 110-pounds, this creature is called Arthropleura and is the largest arthropod to ever live.

This all happened during the Carboniferous period, roughly 300 million to 360 million years ago. The Earth’s atmosphere at that time was rich with oxygen, making it possible for some animals to swell to monstrous size, such as dragonflies with two-foot wingspans.

However, Arthropleura fossils discovered since the 1800s were often only remnants of headless exoskeletons left behind during molting. A new study states researchers have finally pieced together what the animal’s head was like. The breakthrough came from two well-preserved juvenile Arthropleura fossils found in France. These specimens were less than two inches long, but they provided the first-ever glimpse of Arthropleura’s head.

Apparently, this insect’s head was a rough circle adorned with two antennae, a small mandible hidden underneath, and eyestalks protruding from the sides.

Arthropods, are a group of invertebrates that includes crustaceans, spiders, insects, centipedes and millipedes. There has been fierce controversy about Arthropleura’s position on the arthropod family tree since its discovery in 1854. Was it a millipede or a centipede? Scientists weren’t sure.

During examinations of the new, complete fossils, scientists found that it had the body of a millipede but the head of a centipede. It had two pairs of legs per body segment, where centipedes only have one pair per segment. Its jaw position resembles that of a centipede, but its shape and antennae are most similar to those of a millipede. One feature is not seen in any living members of the millipede or centipede families—eyestalks. The eyestalks resemble a crab’s, which could point to the creature having an amphibious youth before becoming terrestrial in adulthood.

Researchers have also concluded that Arthropleura probably chewed on decaying plants like the millipedes of today, rather than hunting prey like a centipede. Its anatomy indicates that it was not carnivorous. It did not have a centipede’s ‘fangs’ or any appendages built for hunting. In addition, having two pairs of legs per segment affected its locomotion and implies it was rather slow.

After piecing together these bits of evidence, the team says the Arthropleura is most closely related to millipedes.

These ancient millipedes lived between 290 million and 346 million years ago, skittering around the Earth’s tropical equator with other massive arthropods, like two-foot-long scorpions. The leading theory for this gigantism is that the oxygen concentration was estimated at 30% during the Carboniferous era compared to the 21% of today. More oxygen in the air may have let insects grow much bigger.

While finding the juvenile Arthropleura has provided some answers, there are more questions to be answered with future fossil discoveries. Did the Arthropleura use tracheae for breathing, or lungs like spiders? That’s just one question that hasn’t been answered yet.

I find modern insects are frequently creepy, at least, to my mind. I definitely do not want to come across a nine-foot-long millipede.

 

https://www.msn.com/en-us/news/technology/fossils-reveal-the-face-of-an-extinct-nine-foot-long-millipede-the-largest-arthropod-to-ever-live/ar-AA1sJDJt?ocid=hpmsn&cvid=ea032899905c4745973f745a67d92256&ei=129