Body length up to 8 mm (excluding the uropods). Cephalothorax as broad as long. with a short, broadly triangular rostrum, with serrated margins and a deflected apex; base showing varying degree of indentation. Eyes present.
Epistome and sternite of thoracomere 2 each with a medial spine. Antero-lateral margins of the pereionites with short, rounded processes. Pleonal epimera prominent, apically truncate and usually highly setose. Pleotelson same length as pleon.
Chelipeds not markedly sexually dimorphic but those of male slightly more robust. In adults there is a prominent tooth on the inner margin of the chelipedal propodus.
It is usually of a porcelain white colour although this is often partially masked by dirt in the grooves on the carapace and attached to the setae.
A. talpa is mainly found on the mid to lower shores associated with mud or sand under stones and in crevices, and from Laminaria holdfasts and coralline algae. It also occurs in the sublittoral zone.
Recorded from the south and west coasts of Britain, the Channel Islands, the Isles of Scilly, the Isle of Man and the east and west coasts of Ireland. There are also records from the Dutch, French and north African coasts.