Arthropleura

Arthropleura armata

Period

Carboniferous

Location

Europe, North America

Length

2-2.6 meters

Weight

50 kg

Diet

Herbivore/Detritivore

Category

Prehistoric Reptiles - Other Reptiles

Family

Arthropleuridae

About Arthropleura

Arthropleura armata

Overview

Arthropleura was the largest land invertebrate ever to exist! This giant millipede-like creature lived during the Carboniferous period, approximately 300 million years ago, and could grow up to 2.6 meters (8.5 feet) long—longer than most humans are tall! Despite its terrifying size, this gentle giant was probably a herbivore that munched on fallen leaves.

Taxonomy & Classification

  • Phylum: Arthropoda
  • Class: Diplopoda (millipedes) or Arthropleuridea
  • Order: Arthropleurida
  • Family: Arthropleuridae
  • Diet: Herbivore/Detritivore

Scientists debate whether Arthropleura was a true millipede or a related group.

Physical Characteristics

Record-Breaking Size

  • Length: Up to 2.6 meters (8.5 feet)
  • Width: Up to 50 cm (20 inches)
  • Weight: Estimated 50 kg (110 lbs)
  • Status: LARGEST LAND INVERTEBRATE EVER

Body Structure

  • About 30 armored segments
  • Two pairs of legs per segment (like millipedes)
  • Heavily armored plates on top
  • Small head with antennae
  • Built like a living tank

Largest Land Invertebrate Ever!

Size Comparison

To understand how big Arthropleura was:

  • Longer than a king-size bed
  • Wider than a dinner plate
  • Heavier than a large dog
  • Could take up an entire sidewalk

No land invertebrate before or since has matched this size!

Why So Big?

High Oxygen Levels

Like other Carboniferous giants, Arthropleura grew huge because:

  • 35% oxygen in the atmosphere
  • Arthropods breathe through tracheae (tubes)
  • More oxygen = larger bodies possible
  • Also had no large predators to worry about

Diet & Lifestyle

Gentle Giant

Despite its scary appearance:

  • Probably ate dead plant matter (detritivore)
  • May have eaten fallen leaves and rotting wood
  • Fossils found with plant spores in gut area
  • Not a predator—too slow to catch prey

Forest Floor Dweller

  • Lived in coal swamp forests
  • Crawled through leaf litter
  • May have been nocturnal
  • Left trackways we can still find today!

Fossil Trackways

Ancient Footprints

We know about Arthropleura from:

  • Body fossils (rare, usually fragments)
  • Trackways (fossilized footprints)
  • Tracks show it could climb over obstacles
  • Found in Scotland, England, North America

In 2021, a giant trackway was found in England!

Discovery

Piecing Together a Giant

  • First described in 1854
  • Only known from fragments for decades
  • Complete picture took 150+ years to assemble
  • Most fossils are armor plates and trackways
  • No complete specimen exists!

Habitat

Carboniferous Forests

Arthropleura lived in:

  • Warm, humid swamp forests
  • Forests of giant ferns, horsetails, clubmosses
  • Near the equator (which was in different positions then)
  • Areas that became coal deposits

Extinction

End of the Giants

Arthropleura disappeared because:

  • Oxygen levels dropped
  • Climate became drier
  • Forests shrank and changed
  • Reptiles evolved and may have competed
  • By the Permian, they were gone

Cool Facts

  • Arthropleura is the LARGEST LAND INVERTEBRATE EVER—bigger than any bug, millipede, or crab alive today!
  • It was up to 2.6 meters long—taller than most NBA players!
  • Despite its size, it was probably a peaceful herbivore
  • We've found its fossilized trackways showing how it walked
  • It had about 30 body segments with armored plates
  • Lived when oxygen levels were 35% (much higher than today's 21%)
  • A 2021 discovery in England found one of the largest trackways ever
  • No complete skeleton has ever been found—we piece it together from fragments!

Arthropleura reminds us that the rules of life were different 300 million years ago—when a millipede could grow longer than a car and wander through forests that would become our coal!