Brady, 1868b
Description:
Carapace medium, 0.6-0.7 mm long, elongate subovate, weakly inflated. Dorsal margin convex, ventral margin weakly sinuous. Fused zone narrow anteriorly, rather broader ventrally and posteriorly. Female relatively higher than male.
Mandible coxa short. Second leg with a chelate knee seta. Third podomere of third leg with a strongly spinose anterior margin. Male copulatory appendage with three distal processes, the anterior one small, the central one large, lamellar, posteriorly acuminate, the posterior one elongate, curved, directed anteriorly (P. hibernicum 5 ). Living specimens light grey with blue-black markings.
Habitat:
Found on intertidal algae.
Remarks:
There has been a great deal of confusion in the past concerning the two species P. hibernicum and P. sarniense, both described by Brady (1868b). The carapace of P. sarniense has a straighter dorsal margin and is more compressed than that of P. hibernicum; the two species also differ in details of their male copulatory appendages. In P. hibernicum the carapace is more elongate than in P. trieri , P. rarum G. W. Müller, 1894 or P. rotundatum G. W. Müller, 1894, species which it resembles in the general form of the carapace and appendages (see also Remarks on P. trieri). It has also been confused in the past (Brady & Norman collections) with P. fleetense, which it superficially resembles in carapace outline but which differs in the shape of the fused zone and the male copulatory appendage.
Distribution:
British Isles; records from elsewhere have proved to be incorrect where we have been able to check them.