[4][5] Maguimithrax spinosissimus has a reddish-brown carapace and walking legs.

The legs are covered with numerous short spines and nodules.

It can reach up to 3 kg of weight and a carapace length of 18 cm.

It inhabits caves and reef underhangs from the shallow intertidal to depths of up to 200 m.[3] It was made the type species of a separate genus Maguimithrax by Klompmaker et al.

[4] Mote Marine Laboratory in Florida is spawning the crabs in hopes they will eat algae and benefit coral reefs.