Appearance
P. elephas may reach up to 60 cm (24 in) long, although rarely longer than 40 cm (16 in), and usually 25–30 cm (10–12 in). Few achieve their maximum weight of several kilograms.
The adults are reddish-brown with yellow spots. The carapace is slightly compressed and lacks lateral ridges. It is covered with forward pointing spines, with the supraorbital spines prominent. The antennae are very heavy and spiny, are tapering and even longer than the body. The first walking leg (pereopod) is provided with subchela (the distal end of a limb developed as a prehensile structure). The fourth segment (merus) of this leg has a characteristic row of spines.

