Adults are up to 65 millimetres (2.6 in) long, with a carapace 32 mm (1.3 in) long; the body is chestnut brown with a green tinge, and the spines projecting from the carapace are red at the tips.

[4] The first pair of pereiopods are 1½ times as long as the body, and have well-developed claws.

[4] It lives between the low water mark and depths of about 70 metres (230 ft),[3] under stones and in rock fissures.

[4] G. squamifera is chiefly nocturnal,[5] and catches passing prey, such as small fish, with its claws.

Species which feed on G. squamifera include the fishes Scorpaena porcus and Serranus atricauda.