The coconut crab, Birgus latro, is the largest land-living arthropod in the world and is probably at the upper limit of how big terrestrial animals with exoskeletons can become in
The Coconut Crab

The coconut crab, Birgus latro, is the largest land-living arthropod in the world and is probably at the upper limit of how big terrestrial animals with exoskeletons can become in