Anonyx edwardsii Krøyer 1846: 41 Sars 1891 : 105 Stephensen 1913 : 121 Onisimus edwardsii Shoemaker 1930: 228 Lowry & Stoddart 1993 :173 Gurjanova 1951 : 162 Boeckosimus edwardsii Barnard 1969: 330 Onisimus edwardsii O. edwardsii O. caricus Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Uristidae) II. The barentsi and edwardsii groups Berge, Jørgen Vader, Wim Johnsen, Jan Roger Zootaxa 2007 1410 55 68 49K8L Kroyer, 1846 Kroyer 1846 [151,577,1501,1527] Malacostraca Uristidae Onisimus Animalia Amphipoda 10 65 Arthropoda species edwardsii    Anonyx edwardsiiKrøyer 1846: 41    Onesimus Edwardsii  Sars 1891: 105;  Stephensen 1913: 121  Onisimus edwardsiiShoemaker 1930: 228;  Lowry & Stoddart 1993:173.  Onisimus edwardsi  Gurjanova 1951: 162   Boeckosimus edwardsiiBarnard 1969: 330    Typelocality  Greenland.   Diagnosis Epimeral plate 3 with slightly upturned tooth. Pereopod 1 propodus clearly longer than carpus, pereopods 3 and 4 propodus with posterior margin with paired robust setae and setae, P4 coxa with moderate posteroventral lobe. Telsoncleft 30%.   Material examined  USNMAcc.no 182783, Indian Harbor, Labrador, 1 spm.  SMNH 6672 det:  O. plautus, male, 9mm, Matoschkin scharr, Belusha viken, 6 spm. TMU xxx, Female, 10mm, Ekkerøy 2–3m; TMU 1168, male, 8 mm, Vardø; TMU 10025, Herwigshavna.   Distribution Stephensen (1923) provided a distribution map of the Atlantic records of  O. edwardsii; as in the case of  O. plautus, there are also here a few old records from S. Norwayand W. Sweden, where the species never has been refound, in spite of extensive collecting; there is even an old, vague record from the Kattegat, dating from Meinert (cf Stephensen 1923b). The most recent Norwegian catalogue ( Vader et al. 1997) only has records from Tromsø (69*50’N) and north, and also here there are only a few reports. Otherwise this species is common and often numerous in the Atlantic Arctic (cf Stephensen 1923, 1935, 1944), and also along the entire arctic coast of RussiaEast to the Chukchi Sea ( Gurjanova 1985, Tzvetkova & Golikov 2001) and in the cold eastern waters of Canada(Shoemaker 1930, 1930b, Dunbar 1954, Brunel et al. 1998) south to Nova Scotia. The species was not present in the extensive collections from Point Barrow, Alaska, however ( Shoemaker 1955), nor does Gurjanova (1962)report on any Pacific material.   Biology    Onisimus edwardsiiis a well-known general scavenger; it is easily and in large numbers collected in baited traps, and has also been found clustering on dead invertebrates in the field (Berge, pers. obs., Vader, pers. obs.).The observations and experiments of Legezynska (2001)have shown that  O. edwardsiiis an opportunistic predator and scavenger, with a wide range of prey animals. She also showed that this species avoids the very turbid waters of the inner fjord basins (where the much larger  O. caricusis absolutely dominant), and only is found in the less turbid outer parts of the fjords. Life cycle data have been collected by Weslawski & Legezynska (2002). The animals appear to be K-strategists and winter breeders, and do not reproduce until they are one year old. The species occurs mostly in very shallow waters in the high arctic, but somewhat lower down in low arctic areas: Stephensen (1944)noted occurrences from 6–36min E. Greenland, Dunbar (1954)from 5 to 20 min Ungava Bay, and Weslawski (1990)from 2–20min the cold Hornsund area of Spitsbergen, with a clear maximum around 15 m( Legezynska et al. 2000). On the other hand, Bryazgin’s data from the Barents Sea noted depths of 30–70m, and also in the Gulf of St Lawrence the animals also occur in the infralittoral ( Brunel et al. 1998, see also Shoemaker 1930a, b).