Cylisticus convexus
Phylum: Arthropoda
Class: Malacostraca
Superorder: Peracarida
Order: Isopoda
Suborder: Oniscidea
Family: Cylisticidae
Genus: Cylisticus
Species: C. convexus
These hardy guys, native to Europe and first described in 1778, have been naturalized in America and can survive in a variety of environments from humid to semi-arid, allowing them to have a surprisingly large range. They can be found in multiple parts of the US, some spots in South America, Europe, and far into Russia. One was even found in Yelizovo, in the far east of Russia across the Sea of Okhotsk. They can roll into a ball similarly to armadillidium species but with their antennae curled over their body on the outside rather than tucked to the side. You can also see their uropods sticking out! Similar to T. rathkii, they have five pairs of lung spots on their underside.
My experience
Recently found tons in a firewood pile. They dart away from me but suddenly stop and quickly ball up. Caught them burrowing a bit too, both into the dirt and into little nooks in the logs.