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