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Onisimus turgidus (Sars, 1879) Figs 4–10 Anonyx turgidus Sars, 1879: no 13. Onisimus turgidus – Sars, 1885: 147, pl. xii, fig. 5, comb. nov. (described as sp. nov.). — Lowry & Stoddart 1993: 169. — Johnsen 2001: 60, fig. 21. — Zimina et al. 2019: 871. Onisimus normani – Stephensen 1923: 48. — Shoemaker 1930: 11. — Vader 1975: 38. — Moore et al. 1994: 206. — Vader & Krapp-Schickel 1996: 65. — Bryazgin 1997: 99. — Lyubina et al. 2014: 246. (These are all not O. normani, but O. turgidus.) Material examined NORWAY • 1 ♀, syntype (15 mm); Barents Sea; 72°53′ N, 21°51′ E; 408 m depth; 30 Jul. 1878; G.O. Sars leg.; stn 323 (trawl), Norwegian North sea Expedition; 1.5°C; silt.; F1764 (Figs 4–6) • 1 ♀ (10 mm); Kuberget Ullsfjorden; 100 m depth; Sep. 1974; Wim Vader leg.; from Actinostola callosa; TSZCr8573. (Figs 7–10) • 1 spec.; Ullsfjorden; from Actinostola callosa; TM IX-95 • 2 specs; Ullsfjorden; 69°39′48″ N, 19°45′18″ E; 106 m depth; 28 Apr. 1995; Wim Vader leg.; from Actinostola callosa; stn JohanRuud 255-95; TSZCr14488 • 21 specs; Ullsfjorden; Jun. 1995; Wim Vader leg.; from Actinostola callosa; stn Hyas 6-95; Arctic University Museum of Tromsø • 1 spec., Finnkroken; 50– 60 fathoms depth; 1900; J. Sparre Schneider leg.; TSZCr1171. Distribution Johnsen (2001) studied samples of presumed Onisimus normani from different parts of the world, and concluded that they all (except the ones from S Norway) belonged in the turgidus species complex; unfortunately there was not sufficient material available to be able to revise this entire complex. The type material was collected from the Barents Sea and it has been collected from this area several times since (Bryazgin 1997; Lyubina et al. 2014, sub nomine O. normani; Zimina et al. 2019). Material from N Norway (Ullsfjorden) is quite similar to the type material, but the animals are smaller, 10 mm against 14 mm for the type. No fully adult or ovigerous specimens of O. turgidus have been found as yet, similar to the situation in O. normani. Onisimus turgidus also spends most of its life inside a sea anemone and like O. normani, likely leaves the host when almost adult. Biology Onisimus turgidus appears to be an obligate associate of sea anemones for most of its life-cycle. The preferred host of Onisimus turgidus in N Norway is Actinostola callosa. The numbers vary quite a lot from year to year (Moore et al. 1994; Vader & Krapp-Schickel 1996: table 2, sub nom. O. normani) but the species is never numerous even there: in 714 specimens of Actinostola Verrill, 1883 from Ullsfjorden 116 specimens of O. turgidus were found, an infection percentage of 0.16 amphipods per host. There is a significant positive correlation between the size of the Actinostola hosts and the number of Onisimus found inside: in the large sample of January 1974 sea anemones of 10–50 g wet weight contained 0.03 amphipods per host, those of 60–100 g 0.54 and the few of 100–150 g 3.00. Actinostola callosa in Ullsfjorden also is the host of another amphipod species, Stenothoe brevicornis Sars, 1883, that likewise feeds on host tissue, but this amphipod lives on the outside of the host, among the tentacles (Moore et al. 1994; Vader & Krapp-Schickel 1996). Onisimus turgidus in Ullsfjorden is also sometimes found inside Bolocera tuediae, the almost exclusive host of O. normani in S Norway (Vader 1973), but here it is even less common than in A. callosa: in 297 specimens of Bolocera Gosse, 1860 from Ullsfjorden only 14 specimens of Onisimus were found (0.05 amphipods per host). The parasitic isopod Parapodascon sp. that is quite common on O. normani in S Norway, has also been found a few times on O. turgidus from the Ullsfjord., Published as part of Vader, Wim, Johnsen, Jan Roger & Tandberg, Anne Helene S., 2020, Onisimus turgidus (Sars, 1879) (Amphipoda, Uristidae), an overlooked amphipod from sea anemones in Northern Norway, pp. 34-50 in European Journal of Taxonomy 724 on pages 40-48, DOI: 10.5852/ejt.2020.724.1155, http://zenodo.org/record/5627470, {"references":["Sars G. O. 1879. Crustacea et Pycnogonida nova in itinere 2 do et 3 tio expeditionis norvegicae anno 1877 & 78 collecta (Prodromus descriptionis). Archiv for Mathematik og Naturvidenskaber 4: 427 - 476.","Sars G. O. 1885. Crustacea I. Norwegian North Atlantic Expedition 1876 - 1878 6 (14): 1 - 280. https: // doi. org / 10.5962 / bhl. title. 2168","Lowry J. K. & Stoddart H. E. 1993. The Onisimus - problem (Amphipoda, Lysianassoidea, Uristidae). Zoologica Scripta 22: 167 - 181. https: // doi. org / 10.1111 / j. 1463 - 6409.1993. tb 00349. x","Johnsen J. R. 2001. The taxonomy of Onisimus. MSc thesis, University of TromsO, Norway.","Zimina O. L., Strelkova N. A. & Lyubina O. S. 2019. Species composition and peculiarities of the distribution of benthic Peracarida (Crustacea, Malacostraca) in the Barents Sea, based on surveys 2003 - 2008. Biology Bulletin (Zoologichesky Zhurnal) 46: 864 - 885. https: // doi. org / 10.1134 / S 1062359019080181","Stephensen K. 1923. Crustacea Malacostraca. V (Amphipoda I). The Danish Ingolf Expedition 3 (8): 1 - 100.","Shoemaker C. R. 1930. The lysianassid amphipod crustaceans of Newfoundland, Nova Scotia, and New Brunswick in the United States National Museum. Proceedings of the United States National Museum 77: 1 - 19. https: // doi. org / 10.5479 / si. 00963801.77 - 2827.1","Vader W. 1975. The sea anemone, Bolocera tuediae, and its copepod parasite, Antheacheres duebeni, in northern Norway. Astarte 8: 37 - 39.","Moore P. G., Rainbow P. S. & Vader W. 1994. On the feeding and comparative biology of iron in coelenterate-associated gammaridean Amphipoda (Crustacea) from N. Norway. Journal of Experimental Marine Biology and Ecology 178: 205 - 231. https: // doi. org / 10.1016 / 0022 - 0981 (94) 90037 - X","Vader W. & Krapp-Schickel G. 1996. Redescription and biology of Stenothoe brevicornis Sars (Amphipoda: Crustacea), an obligate associate of the sea anemone Actinostola callosa (Verrill). Journal of Natural History 30: 51 - 66. https: // doi. org / 10.1080 / 00222939600770041","Bryazgin V. 1997. Diversity, distribution and ecology of benthic amphipods (Amphipoda, Gammaridea) in the Barents Sea sublittoral. Polish Polar Research 18: 89 - 106.","Lyubina O. S., Bryazgin V. F. & Raznovskaya S. V. 2014. The composition and distribution of benthic amphipods (Crustacea: Amphipoda) in the southern Barents Sea. Russian Journal of Marine Biology 40: 241 - 254. https: // doi. org / 10.1134 / S 1063074014040063","Vader W. & Lonning S. 1973. Physiological adaptations in associated amphipods. A comparative study of tolerance to sea anemones in four species of Lysianassidae. Sarsia 53: 29 - 40. https: // doi. org / 10.1080 / 00364827.1973.10411245"]}

Onisimus normani Sars, 1891 Figs 1–3 Onesimus normani (Schneider ms) Sars, 1891: figs on pl. 36–2. Onesimus normani – Sars, 1895: 105. Onisimus normani – Stephensen 1923: 48; 1935: 38. — Vader 1967: 286, figs 2–3; 1975: 38; 1983: 144. — Vader & Lønning 1973: 29. — Lowry & Stoddart 1993: 169. — Johnsen 2001: 49, fig. 17. non O. normani – Stephensen 1923: 48. — Shoemaker 1930: 11. — Vader 1975: 38. – Moore et al. 1994: 206. — Vader & Krapp-Schickel 1995: 65. — Bryazgin 1997: 99. — Lyubina et al. 2014: 246. (All these references = O. turgidus (Sars, 1879).) Material examined NORWAY • 1 ♀ (10 mm); Korsfjorden; 680 m depth; 1968; Wim Vader leg.; from Bolocera tuediae; TSZCr8659 (Figs 1–3) • 1 ♀ immature (8 mm); same collection data as for preceding; TSZCr8659 • 1 spec.; Raunefjorden; 240 m depth; 1968; Wim Vader leg.; from Bolocera tuediae; TSZCr8628 • 1 spec.; Korsfjorden; 680 m depth; 1968; Wim Vader leg.; from Bolocera tuediae; TSZCr8623 • 1 spec.; same collection data as for preceding; TSZCr8624 • 2 specs; same collection data as for preceding; TSZCr9320 • 7 specs; Andfjorden; 69°18′42″ N, 16°23′24″ E; 498 m depth; 1 Jul. 1997; Wim Vader leg.; from Bolocera tuediae; TSZCr12962 Distribution Although there are many records of O. normani in the amphipod literature, all except those from Southern Norway in reality are either O. turgidus or taxa very closely related to that species (Johnsen 2001). Johnsen mentions a record from Andsfjorden at 69° N (material in Tromsø Museum): otherwise this species has only been recorded from the Oslofjord and a number of localities in W Norway (Vader 1967). Onisimus normani appears to be an obligate associate of the sea anemone Bolocera tuediae, and it has only exceptionally been found in other sea anemones (Vader 1967, 1975), although it is well able to survive also in other sea anemone hosts in the laboratory (Vader & Lønning 1973)., Published as part of Vader, Wim, Johnsen, Jan Roger & Tandberg, Anne Helene S., 2020, Onisimus turgidus (Sars, 1879) (Amphipoda, Uristidae), an overlooked amphipod from sea anemones in Northern Norway, pp. 34-50 in European Journal of Taxonomy 724 on pages 36-40, DOI: 10.5852/ejt.2020.724.1155, http://zenodo.org/record/5627470, {"references":["Stephensen K. 1923. Crustacea Malacostraca. V (Amphipoda I). The Danish Ingolf Expedition 3 (8): 1 - 100.","Stephensen K. 1935. The Amphipoda of N. Norway and Spitsbergen with adjacent waters. TromsO Museums Skrifter 3: 1 - 140.","Vader W. 1967. Notes on Norwegian marine amphipods 1 - 3. Sarsia 29: 283 - 294. https: // doi. org / 10.1080 / 00364827.1967.10411089","Vader W. & Lonning S. 1973. Physiological adaptations in associated amphipods. A comparative study of tolerance to sea anemones in four species of Lysianassidae. Sarsia 53: 29 - 40. https: // doi. org / 10.1080 / 00364827.1973.10411245","Lowry J. K. & Stoddart H. E. 1993. The Onisimus - problem (Amphipoda, Lysianassoidea, Uristidae). Zoologica Scripta 22: 167 - 181. https: // doi. org / 10.1111 / j. 1463 - 6409.1993. tb 00349. x","Johnsen J. R. 2001. The taxonomy of Onisimus. MSc thesis, University of TromsO, Norway.","Shoemaker C. R. 1930. The lysianassid amphipod crustaceans of Newfoundland, Nova Scotia, and New Brunswick in the United States National Museum. Proceedings of the United States National Museum 77: 1 - 19. https: // doi. org / 10.5479 / si. 00963801.77 - 2827.1","Vader W. 1975. The sea anemone, Bolocera tuediae, and its copepod parasite, Antheacheres duebeni, in northern Norway. Astarte 8: 37 - 39.","Moore P. G., Rainbow P. S. & Vader W. 1994. On the feeding and comparative biology of iron in coelenterate-associated gammaridean Amphipoda (Crustacea) from N. Norway. Journal of Experimental Marine Biology and Ecology 178: 205 - 231. https: // doi. org / 10.1016 / 0022 - 0981 (94) 90037 - X","Bryazgin V. 1997. Diversity, distribution and ecology of benthic amphipods (Amphipoda, Gammaridea) in the Barents Sea sublittoral. Polish Polar Research 18: 89 - 106.","Lyubina O. S., Bryazgin V. F. & Raznovskaya S. V. 2014. The composition and distribution of benthic amphipods (Crustacea: Amphipoda) in the southern Barents Sea. Russian Journal of Marine Biology 40: 241 - 254. https: // doi. org / 10.1134 / S 1063074014040063","Sars G. O. 1879. Crustacea et Pycnogonida nova in itinere 2 do et 3 tio expeditionis norvegicae anno 1877 & 78 collecta (Prodromus descriptionis). Archiv for Mathematik og Naturvidenskaber 4: 427 - 476.","Sars G. O. 1890 - 1895. An Account of the Crustacea of Norway, with short Descriptions and Figures of all the Species. Vol. 1. Amphipoda. Alb. Cammermeyers Forlag, Christiania and Copenhagen. https: // doi. org / 10.5962 / bhl. title. 1164"]}

Onisimus Boeck, 1871 (Fig. 27) Onisimus Boeck, 1871: 111.— Stebbing 1906: 25.—Schellenberg 1927: 659.— Stephensen 1929: 53.— Gurjanova 1951: 161.—J.L. Barnard 1969: 352.— Barnard & Karaman 1991: 506.— Lowry & Stoddart, 1993: 168.—Vader, Johnsen & Berge, 2005: 2. Onesimus Boeck, 1876: 161 (invalid emendationof Onisimus Boeck, 1871).—G.O. Sars 1891: 104. Pseudalibrotus Della Valle, 1893: 798.— Stebbing 1906.—33.—Schellenberg 1927: 671.— Stephensen 1929: 55 (type species: Anonyx litoralis Boeck, 1871, monotypy). Alibrotus Sars, 1891: 101. Paronesimus Stebbing, 1894: 14.— Stebbing 1906: 43.— Gurjanova 1951: 196.— Barnard 1969: 357.— Barnard & Karaman 1991: 516 (type species: Paronesimus barentsi Stebbing, 1894, monotypy). Boeckosimus J.L. Barnard, 1969: 330.— Barnard & Karaman 1991: 470 (type species: Anonyx edwardsii Krøyer, 1846, original designation). Type species. Anonyx litoralis Krøyer, 1845, selected by Boeck, 1876. Included species. Onisimus includes 26 species: O. abyssi Oldevig, 1959; O. affinis Hansen, 1887; O. barentsi (Stebbing, 1894); O. birulai (Gurjanova, 1929b); O. botkini Birula,1897; O. brevicaudatus Hansen, 1887; O. caspius (G.O. Sars, 1896); O. caricus Hansen, 1887; O. derjugini (Gurjanova, 1929a); O. dubius Schellenberg, 1935 b; O. edwardsii Krøyer, 1846; O. glacialis (G.O. Sars, 1900); O. krassini Gurjanova, 1951); O. leucopis G.O. Sars, 1879; O. litoralis (Krøyer, 1845); O. nanseni (G.O. Sars, 1900); O. normani G.O. Sars, 1891; O. platyceras (G.O. Sars, 1896); O. plautus Krøyer, 1845; O. punctatus (Bate, 1862); O. sextonae Chevreux, 1926; O. sibiricus Brüggen, 1909; O. simus Gurjanova, 1962; O. turgidus G.O. Sars, 1879; O. uschakovi (Gurjanova, 1933); O. zenkevitchi Mednikov, 1960. Nomina nuda. Onisimus abyssicola (Stuxberg, 1880); O. crassini (Gorbunov, 1946); O. vorax (Stuxberg, 1880); O. zebra (Stuxberg, 1880). Diagnostic description. Antenna 1 peduncle article 1 without anterodistal lobe; accessory flagellum forming cap covering callynophore. Antenna 2 without brush setae. Mandible molar a column with fully triturating surface. Maxilla 1 outer plate a well developed 7/4 crown. Maxilla 2 inner plate significantly shorter than outer plate. Gnathopod 1 subchelate; coxa 1 large, about as long as coxa 2, subrectangular with concave anterior margin ; ischium short (length less than 2 × breadth); carpus short (length 1 to 2 × breadth); propodus margins slightly tapering distally. Uropod 2 inner ramus with or without constriction. Telson entire to moderately cleft. Remarks. Based on the morphology of gnathopod 1 Onisimus and Anonyx are very similar. Onisimus retains the triturating molar characteristic of tryphosine amphipods while Anonyx has a derived setose tongue., Published as part of Lowry, J. K. & Kilgallen, N. M., 2014, A generic review of the lysianassoid family Uristidae and descriptions of new taxa from Australian waters (Crustacea, Amphipoda, Uristidae), pp. 1-92 in Zootaxa 3867 (1) on page 45, DOI: 10.11646/zootaxa.3867.1.1, http://zenodo.org/record/5585734, {"references":["Boeck, A. (1871) Crustacea Amphipoda borealia et arctica. Forhandlinger i Videnskabs-Selskabet i Christiania, 1870, 81 - 280, i - viii. [index] http: // dx. doi. org / 10.5962 / bhl. title. 2056","Stebbing, T. R. R. (1906) Amphipoda. I. Gammaridea. Das Tierreich, 21, 1 - 806.","Stephensen, K. (1929) Amphipoda. Die Tierwelt der Nord- und Ostsee, 14, 1 - 188.","Gurjanova, E. F. (1951) Amphipods of the seas of the USSR and surrounding waters (Amphipoda-Gammaridea). Akademiya Nauk SSSR, Opredeliteli po Faune SSSR, 41, 1 - 1029.","Barnard, J. L. (1969) The families and genera of marine gammaridean Amphipoda. Bulletin of the United States National Museum, 271, 1 - 535. http: // dx. doi. org / 10.1163 / 156854082 x 00632","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. http: // dx. doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Lowry, J. K. & Stoddart, H. E. (1993) The Onisimus problem (Crustacea, Amphipoda, Lysianassoidea). Zoologica Scripta, 22, 167 - 181. http: // dx. doi. org / 10.1111 / j. 1463 - 6409.1993. tb 00349. x","Boeck, A. (1876) De Skandinaviske og Arktiske Amphipoder. Part 2. A. W. Brogger, Christiania, pp. 1 - 713, pls. 168 - 132. http: // dx. doi. org / 10.5962 / bhl. title. 10131","Sars, G. O. (1891) An Account of the Crustacea of Norway, with Short Descriptions and Figures of all the Species. Vol. I. Amphipoda. Parts 4 - 9. Alb. Cammermeyer, Christiana, 144 pp., 48 pls. [pp. 69 - 212, pls. 225 - 272]","Della Valle, A. (1893) Gammarini del Golfo di Napoli. Fauna und Flora des Golfes von Neapel, 20, 1 - 948, pls. 941 - 961. http: // dx. doi. org / 10.5962 / bhl. title. 3710","Stebbing, T. R. R. (1894) The Amphipoda collected during the voyages of the Willem Barents in the Arctic Seas in the years 1880 - 1884. Bijdragen tot de Dierkunde, 17, 1 - 48, pls. 41 - 47.","Kroyer, H. N. (1846) Atlas des Crustaces. Voyages de la commission scientifique du nord; en Scandinavie, en Laponie, au Spitzberg et aux Fero, pendant les annees 1838 - 1840, sur la corvette la Recherche, commandee par M. Fabvre. In: Voyages de la commission scientifique du nord; en Scandinavie, en Laponie, au Spitzberg et aux Fero, pendant les annees 1838 - 1840, sur la corvette la Recherche, commandee par M. Fabvre. Paul Gaimard, Paris, pp. 10, 11, 13 - 20, 22, 23.","Kroyer, H. N. (1845) Karcinologiske Bidrag. Naturhistorisk Tidsskrift, Series 2, 1, 283 - 345, pls. 281 - 283; 403; 453 - 638, pls. 286, 287.","Oldevig, H. (1959) Arctic, subarctic and Scandinavian amphipods in the collections of the Swedish Natural History Museum in Stockholm. Goteborgs Kungliga Vetenskaps- och Vitterhets-Samhalles Handlingar, Series B, 8, 1 - 132, plates 1 - 134.","Hansen, H. J. (1887) Oversigt over de paa Dijmphna-Togtet indsamlede Krebsdyr. In: Lutken, C. F. (Ed.), Dijmphna-Togtets Zoologisk-botaniske Ubdytte. Kjobenhavn, pp. 183 - 286, pls. 120 - 124.","Gurjanova, E. F. (1929 b) Neue Formen arktischer Isopoden und Amphipoden. Zoologischer Anzeiger, 81, 309 - 317, 8 figs. [not seen]","Birula, A. A. (1897) Recherches sur la biologie et zoogeographie, principalement des mers russes. II. Hydrozoaires, polychetes et crustaces, recueillis par le Dr. A. Botkine en 1895 dans les golfes du Enisei et de l'Obi. Annuaire du Musee Zoologique de l'Academie Imperiale des Sciences de St. Petersbourg, 2, 78 - 116, pls. 119, 110.","Sars, G. O. (1896) Crustacea Caspia. Contributions to the knowledge of the carcinological fauna of the Caspian Sea. Amphipoda. Supplement. Bulletin de l'Academie Imperiale des Sciences de St. - Petersbourg, Series 5, 4, 421 - 489, pls. 421 - 412.","Gurjanova, E. F. (1929 a) On the fauna of Crustacea Malacostraca of the Barents Sea, White Sea and Kara Sea. Travaux de la Societe des Naturalistes de Leningrad, 59, 29 - 46, 7 figs. [in Russian]","Schellenberg, A. (1935) Die Amphipoden der Norwegischen Expeditionen nach Ost-Gronland in den Jahren 1929, 1930, 1931 und 1932. Skrifter om Svalbard og Ishavet, Oslo, 66, 9 - 39.","Sars, G. O. (1900) Crustacea. The Norwegian North Polar Expedition 1893 - 1896. Scientific Research, 1 (5), 137 pp., 36 pls.","Sars, G. O. (1879) Crustacea et Pycnogonida nova in itinere 2 do et 3 tio expeditionis Norvegicae anno 1877 & 78 collecta (Prodromus descriptionis). Archiv for Mathematik og Naturvidenskab, Kristiania, 4, 427 - 476.","Bate, C. Spence (1862) Catalogue of the specimens of Amphipodous Crustacea in the collection of the British Museum. Printed by order of the Trustees [by Taylor and Francis], London, 399 pp. http: // dx. doi. org / 10.5962 / bhl. title. 20901","Chevreux, E. (1926) Diagnoses d'amphipodes nouveaux provenant des campagnes de la \" Princesse-Alice \", dans l'Atlantique et dans l'Ocean Arctique. Lysianassidae. Bulletin de l'Institut Oceanographique, Monaco, 475, 1 - 12.","Bruggen, E. (1909) Beitrage zur Kenntnis der Amphipoden-Fauna der russichen Arctis. Memoirs of the Academy of Science, St- Petersbourg, Series 8, 18, 1 - 57.","Gurjanova, E. F. (1962) Amphipods of the northern part of the Pacific Ocean (Amphipoda-Gammaridea). Part 1. Akademiya Nauk SSSR, Opredeliteli po Faune SSSR, 74, 1 - 440.","Gurjanova, E. F. (1933) Zur Amphipodenfauna des Karischen Meeres. Zoologischer Anzeiger, 103, 119 - 128.","Mednikov, B. M. (1960) [Review of the genus Pseudalibrotus Della-Valle (Amphipoda) in marine waters of the far east]. Biologicheskie Nauki, Moskva, 3, 10 - 13.","Stuxberg, A. (1880) Evertebratfaunan i Sibiriens Ishaf. Forelopande studies grundade pa de zoologiska undersokningarna under Prof. A. E. Nordenskiolds Ishafs-expedition 1878 - 79. Bihang till Kunliga Svenska Vetenskaps-Akademiens Handlingar, 5, 1 - 76.","Gorbunov, G. (1946) Bottom life of the Novosiberian shoalwaters and the central part of the Arctic Ocean. Works of Drifting Ice Expedition in the Central Arctic Ocean in Ice Breaking Steamer \" T. Sedov \", pp. 30 - 128, 121 plate."]}

Onisimus simus Gurjanova, 1962 Onisimus simus Gurjanova, 1962: 62. Type locality Okhotsk Sea Distribution Okhotsk Sea (Gurjanova 1962), Storfjorden at Spitsbergen (Bryazgin, 1973). Biology Maximum length 10.5mm. Depth: 125m (Type-locality). Bryazgin (1973) collected the species in Storfjorden at a depth of 100m in cold water (-1.8��C). Ovigerous females had a maximum of 9 eggs. Remarks The type material of this species was examined in the Zoological Institute of St. Petersburg, but the material was not suitable for making detailed descriptions. Professor Valery Bryazgin (1973), however, gives the following details about his Storfjorden specimen. Barents sea specimens vary from Gurjanova���s description of Okhotsk Sea material in several ways: The surface is without granular black pigment, but has small pits with microscopic setules. Eyes light, almost invisible in alcohol. Antenna 1 peduncle article 1 with large dorso-distal protuberance, that is longer than peduncle articles 2 + 3. Peduncle article 1 with 3 plumose setae on ventrodistal margin. Flagellum with first article much longer than in typical material, and with 2 parallel rows of slender setae, flagellum 10 - to 11 - articulate, accessory flagellum with 6 articles. Antenna 2 flagellum with 14 articles. Pereopod 1���2: Typical for the most part, but pereopod 2 propodus with oblique palm, distal protuberance present on palm (contra Gurjanova���s description). Telson cleft 1 / 3, lobes with distal bifurcation, with small setae in the ���bifurcations���., Published as part of Berge, J��rgen, Vader, Wim & Johnsen, Jan Roger, 2007, Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Uristidae) II. The barentsi and edwardsii groups, pp. 55-68 in Zootaxa 1410 on pages 64-65, DOI: 10.5281/zenodo.175595, {"references":["Gurjanova, E. F. (1962). Bokoplavy severnoi chasti Tixogo Okeana (Amphipoda-Gammaridea), chast' 1. Akademiia Nauk SSSR, Opredeliteli po Fauna SSSR, 74, 1 - 440."]}

Onisimus barentsi (Stebbing, 1894) Figure 1���4 Paronesimus barentsi Stebbing 1894: 14; Stephensen 1932: 354, 1935: 51; Gurjanova 1936: 34, 1951: 198, 1962: 143; Dunbar 1954: 715; Shoemaker 1955: 6; Barnard 1958: 98; Brunel 1970: 35; Watling 1979: 266; Palerud & Vader 1991: 42. Onisimus barentsi Lowry & Stoddart 1993: 176 Onisimus krassini Gurjanova 1951: 175. New synonomy. Type locality West of Novaja Zemlya: 75 �� 49 'N 53 �� 42 'E, 125m. Diagnosis Antenna 1 peduncle article 1 produced anterodistally (nose). Uropod 1 peduncle length about 1.5 times rami. Cephalic lobe rounded. Coxa 1 expanded ventrally. Pereopod 1 propodus length 1.5 times carpus length, palm clearly shorter than dactylus. Telson cleft 40 %. Material examined CRU, female, 12mm, Godthaab-Exp St 139, 71 �� 21 ��� N 54 �� 29 ��� W. Greenland, 1 spm. (Det: O. plautus.); CMNC 1998 -0010, female 5mm, Northumberland Canada, 35m; Type material of O. krassini at the ZMS. Description (based upon female 12mm, adult) Head and body: Head as long as pereon 1. Cephalic lobe little extended forward, rounded, dorsal margin straight and ventral margin convex. Eyes oval. Urosomite 1 with slight dorsal depression. Antennae: Antenna 1 as long as cephalon and next 1.5 body segment; peduncle article 1 slightly longer than head, longer than deep, produced anterodorsally; accessory flagellum length 0.6 times primary flagellum, 5 -articulate, article 1 clearly shorter than the rest of flagellum, as long as primary flagellum article 1; primary flagellum 0.9 times peduncle, 10 -articulate, article 1 as long as next 3 articles combined; callynophore present; calceoli absent on flagellum. Antenna 2 about 1.2 times as long as antenna 1; flagellum 12 -articulate; peduncle article 4 clearly longer than article 5, article 5 as long as the three first articles in flagellum; calceoli absent on flagellum. Mouthparts: Epistome and labrum weakly convex, labrum not in front of epistome. Mandible incisor with convex margin; left lacinia mobilis present; 3 accessory setae present on left and right mandible; molar oval and not triturate; palp attached opposite molar, article 1 without setae, article 2 longer than 3, article 2 with 14 distoventral setae, article 3 with 23 distoventral setae. Maxilla 1 with 2 plumose setae on inner plate; outer plate with ST in 7 / 4 -crown arrangement; palp large, 2 -articulate, distally with 7 robust setae and one distolateral simple seta, distomedial margin serrate. Maxilliped inner plate distally with 3 nodular setae, inner and medial setae rows present and almost continuous, setae pappopectinate, distal setae row reduced, 1 simple seta; outer plate subovate, without subapical notch, distal setae group with 2 robust setae, inner setae row with 8 simple setae, outer setae row with 14 short robust setae; palp 4 -articulate, unguis present on dactyl. Pereopods: Pereopod 1 subchelate, coxa subrectangular but slightly expanded ventrally, upper anterior margin slightly concave, anteroventral corner subangular, ventral margin straight, posterior margin weakly convex with a little notch, medial setae present; basis 2 times as long as broad, strong setation along anterior margin and weak setation along posterior margin; ischium length posterior margin> breadth, with 4 medioventral setae-groups; merus shorter than ischium; carpus as long as merus, carpal lobe absent; propodus length 1.5 times carpus, slightly tapering distally, length> 2 times breadth; palm slightly oblique, nearly transverse, convex and serrate, corner clearly defined with 2 slender robust setae; dactylus longer than palm, accessory tooth present, cuticular teeth along posterior margin. Pereopod 2: Missing. Pereopod 3: Missing. Pereopod 4 coxa anterior margin convex, moderate posteroventral lobe; merus without mediolateral setae row; propodus without setae row along anterior margin, posterior margin with 4 slender setae and 5 short robust setae, 2 apical robust setae. Pereopod 5 coxa equilobate; basis with anterior margin weakly concave, robust setae present; basis expanded with posterior margin crenulate, convex, no submarginal spine-row; merus expanded posterodistally, length anterior margin shorter than breadth, 3 robust setae present on posterior margin; propodus anterior margin with 4 paired short robust setae and 2 apical robust setae. Pereopod 6 coxa small, lobate posteriorly; basis expanded posteriorly with crenulate margin, convex, posteroventral corner rounded; merus expanded posterodistally, length anterior margin equal breadth, 4 robust setae present on posterior margin; propodus anterior margin with 4 paired short robust setae and 2 apical robust setae. Pereopod 7 basis expanded posteriorly with crenulate posterior margin, convex; merus slightly expanded posterodistally, anterior margin longer than breadth, 4 robust setae on posterior margin; propodus anterior margin with 4 paired short robust setae, the rest of the limb missing. Gills and oostegites: Gills on pereopods 2���6, fully developed with extra lobe on P 5 and P 6; Oostegites on pereopods 2���5. Epimeral plates: Epimeral plate 1 anteroventral corner rounded, not produced, ventral margin straight, posteroventral corner subrounded. Epimeral plate 2 anteroventral corner rounded, ventral margin straight, posteroventral corner subangular. Epimeral plate 3 anteroventral corner rounded, ventral margin straight; posteroventral corner produced into a horizontal tooth. Uropods: Uropod 1 peduncle longer than rami (1.5 times), outer margin with 5 robust setae, inner margin with 6 robust setae; outer ramus slightly longer than inner, with 4 robust setae on outer margin; inner ramus with 4 robust setae on outer margin. Uropod 2 peduncle equal to rami, outer margin with 6 robust setae, inner margin with 1 apical robust seta; rami subequal; outer ramus with 4 robust setae on outer margin; inner ramus without constriction, with 3 robust setae on outer margin. Uropod 3 peduncle equal to rami, with 1 medioapical robust seta and 2 apical robust setae on inner margin; outer ramus partly broken; inner ramus without robust setae. Telson: Longer than broad (1.4 times), rectangular, weakly convex and narrowing distally, cleft 40 %, incision deeper than broad, with 2 dorsolateral setae and 1���2 apical setae on each lobe. Distribution Circum-arctic; the most recent Russian survey of the distribution of arctic amphipods (Tzvetkova & Golikov 2001) recorded Onisimus barentsi from the Barents, Kara and Chukchi Seas, and its synonym O. krassini additionally from the Laptev and East Siberian Seas. Gurjanova (1962) reported this species also from the Bering and Ochotsk Seas, as well as from off Sakhalin and from the Japan Sea; for O. krassini she gave records from the same area, but also including Korea. The species has never been recorded from Japanese waters (Ishimaru 1994). In the western Palaearctic, there are records from Ungava Bay, Canada (Dunbar 1954) and Point Barrow, Alaska (Shoemaker 1955), as well as from the St Laurens estuary (cf Brunel et al. 1998). Dunbar (1954) concluded ���It is probably a species of Pacific origin which has spread both east and west of the Bering Sea along the Siberian and North American coasts and it is to be expected that it will be taken in due course in Eastern Siberia and North America.��� This expectation has come true and Dunbar���s hypothesis seems still valid. Biology Little is known, although some Russian data may have been overlooked. Bryazgin (1997, sub O. krassini) collected the species from 94m on a clay and silt bottom, Gurjanova���s (1962) records from the NW Pacific are from 43���110m, but in the East-Siberian Sea the species has been collected from as shallow as 10m (Golikov & Tzvetkova 1994). Dunbar recorded the species at three stations, from 12���120m depths, and Brunel (1970, sub Paronesimus, Brunel et al. 1998) collected material in the St Lawrence estuary between 20 and 180 m. This species has not been reported from baited traps. Remarks The only deviation from Lowry and Stoddart���s (1993) redescription of the holotype is the presence of 3 accessory setae on both the right and left mandible. Examination of the type material of O. krassini in the Zoological Museum of St Petersburg revealed no observable differences between the two nominal taxa. Onisimus krassini is hence considered as a junior synonym of O. barentsi., Published as part of Berge, J��rgen, Vader, Wim & Johnsen, Jan Roger, 2007, Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Uristidae) II. The barentsi and edwardsii groups, pp. 55-68 in Zootaxa 1410 on pages 56-59, DOI: 10.5281/zenodo.175595, {"references":["Stebbing, T. R. R. (1894) The Amphipoda collected during the voyages of the Willem Barents in the arctic seas in the years 1880 - 1884. Bijdragen tot de Dierkunde, 17, 1 - 48","Stephensen K. (1932) Some new amphipods from Japan. Annotationes Zoologicae Japonensis, 13, 487 - 501.","Gurjanova, E. F. (1936) Neue Beitrage zur Fauna der Crustacea-Malacostraca des arktischen Gebietes. Zoologischer Anzeiger, 113, 245 - 255.","Dunbar, M. J. (1954) The amphipod Crustacea of Ungava bay, Canadian Eastern Arctic. Journal of the Fisheries Research Board of Canada, 11, 709 - 798.","Shoemaker, C. R. (1955). Amphipoda collected at the Arctic Laboratory, Office of Naval Research, Point Barrow, Alaska, by G. E. MacGinitie. Smithsonian Miscellaneous Collections 128, 1 - 78.","Barnard JL. (1958) Index to the families, genera, and species of the gammaridean Amphipoda (Crustacea). Allan Hancock Foundation Publications Occasional Papers, 19, 1 - 145.","Brunel, P. (1970) Catalogue d'invertebres benthiques du golfe Saint-Laurent recueillis de 1951 a 1966 par la station de biologie marine de Grande-Riviere. Universite de Montreal, Travaux de Biologie, 53, 1 - 55.","Watling L. (1979) Zoogeographic affinities of northeastern North American gammaridean Amphipoda. Bulletin of the Biological Society of Washington, 3, 256 - 282.","Palerud R, & Vader W. (1991) Marine Amphipoda Gammaridea in north-east Atlantic and Norwegian Arctic. Tromura Naturvitenskap, 68, 1 - 97.","Lowry, J. K. & Stoddart, H. E. (1993). The Onisimus problem (Amphipoda, Lysianassoidea, Uristidae). Zoologica Scripta, 22, 167 - 181.","Gurjanova, E. F. (1951). Bokoplavy morej SSSR i sopredel'nykh vod (Amphipoda-Gammaridea). Akademiia Nauk SSSR, Opredeliteli po Faune SSSR, 41, 1 - 1029.","Tzvetkova, N. L. & Golikov, A. A. (2001) Amphipoda-Gammaridea. Pp 79 - 94 in B. I. Sirenko (ed.). List of species of free-living invertebrates of Eurasian Arctic seas and adjacent deep waters. Russian Academy of Sciences, Zoological institute. Explorations of the Fauna of the Seas 51, St. Petersburg.","Gurjanova, E. F. (1962). Bokoplavy severnoi chasti Tixogo Okeana (Amphipoda-Gammaridea), chast' 1. Akademiia Nauk SSSR, Opredeliteli po Fauna SSSR, 74, 1 - 440.","Ishimaru, S. (1994) A catalogue of gammaridean and ingolfiellidean Amphipoda recorded from the vicinity of Japan. Report of the Sado Marine Biological Station, Niigata University, 24, 29 - 86.","Brunel, P., Bosse, L. & Lamarche, G. (1998) Catalogue des Invertebres marins de l'estuaire et du golfe du Saint-Laurent. Publication Speciale Canadienne des Sciences Halieutiques et Aquatiques, 126, 1 - 405.","Bryazgin, V. (1997) Diversity, distribution and ecology of benthic amphipods (Amphipoda, Gammaridea) in the Barents Sea sublittoral. Polish Polar Research, 18, 89 - 100.","Golikov, A. A. & Tzvetkova, N. L. (1994) (Amphipoda (Amphipoda, Gammaridea) of the Chaun bay of the East Siberian Sea. Pp 211 - 249 in O. A. Scarlato (ed.) (Ecosystems and the flora and fauna of the Chaun bay of the East Siberian Sea.) Russian Academy of Sciences, Zoological Institute. Explorations of the Fauna of the Seas 47, St. Petersburg. (In Russian)"]}

Onisimus sibiricus Br��ggen, 1909 Figure 9 Onisimus sibiricus Br��ggen 1909: 8, Gurjanova 1951: 164. Distribution and biology This species was originally described from the Kara Sea (Br��ggen 1909), while Gurjanova (1951) added specimens from the Chukotsk Sea. Gurjanova���s map in Atlas Arktiki (Gurjanova 1985) shows a few localities in the Laptev Sea, one in the westernmost East Siberian Sea, and one most unexpected dot in the Norwegian Sea south of Bear Island, but Bryazgin (1987) does not mention the species from his extensive Barents Sea collections, and Tzvetkova & Golikov (2001) only report O. sibiricus from the Kara, Laptev, East Siberian and Chukotsk Seas, not from the Barents Sea. Thus, the distribution area, as presently known, seems to stretch from the Kara Sea almost to the Bering Strait, with most records in quite shallow water. O. sibiricus has been collected from a wide array of bottom substrates (Golikov & Tzvetkova 1994, data from Chaun Bay, East Siberian Sea). The biology of this species is otherwise completely unknown; it has never been collected from baited traps. Remarks Material of this species was examined in the collections of the Zoological Institute of St.Petersburg. Examination of this material did not reveal any differences between O. plautus and O. sibiricus. Br��ggen, in his original description of the species in 1909, describes it as close to O. plautus, differing primary in size of coxa and in P 2 propodus. However, as type material of the two species was not available for examination, the two species are herein treated as distinct taxa. No further descriptions are given, except the illustration of habitus (see figure 9)., Published as part of Berge, J��rgen, Vader, Wim & Johnsen, Jan Roger, 2007, Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Uristidae) II. The barentsi and edwardsii groups, pp. 55-68 in Zootaxa 1410 on pages 63-64, DOI: 10.5281/zenodo.175595, {"references":["Bruggen, E. von der (1909) Beitrage zur Kenntnis der Amphipoden-Fauna der Russischen Arctis. Memoires de l'Academie Imperiale des Sciences de St. Petersbourg, Ser. 8, Physico-Mathematique Classe, 18 (16), 1 - 56.","Gurjanova, E. F. (1951). Bokoplavy morej SSSR i sopredel'nykh vod (Amphipoda-Gammaridea). Akademiia Nauk SSSR, Opredeliteli po Faune SSSR, 41, 1 - 1029.","Gurjanova, E. F. (1985) (Bottom Crustacea, species of endemic genera Onisimus (Amphipoda) and Katianira (Isopoda) and deep-sea endemic species of Eurycope (Isopoda) and Gnathia (Gnathiidea).). P. 130 in Atlas Arktiki, Moskva 1985, 204 pp. (in Russian)","Tzvetkova, N. L. & Golikov, A. A. (2001) Amphipoda-Gammaridea. Pp 79 - 94 in B. I. Sirenko (ed.). List of species of free-living invertebrates of Eurasian Arctic seas and adjacent deep waters. Russian Academy of Sciences, Zoological institute. Explorations of the Fauna of the Seas 51, St. Petersburg.","Golikov, A. A. & Tzvetkova, N. L. (1994) (Amphipoda (Amphipoda, Gammaridea) of the Chaun bay of the East Siberian Sea. Pp 211 - 249 in O. A. Scarlato (ed.) (Ecosystems and the flora and fauna of the Chaun bay of the East Siberian Sea.) Russian Academy of Sciences, Zoological Institute. Explorations of the Fauna of the Seas 47, St. Petersburg. (In Russian)"]}

Onisimus plautus (Kr��yer, 1845) Figure 5���8 Type locality South East Greenland. Diagnosis Antenna 1 peduncle anterodorsally produced. Uropod 1 peduncle weakly longer than rami. Cephalic lobe triangular and acute. Coxa 1 rectangular (not expanded ventrally). Pereopod 1 propodus as long as carpus, dactylus as long as palm. Telson cleft 1 / 3. Material examined USNM 119980, Dolphin and Union Strait, Canada, 2 spm. F 13184, Karm��y, Norway, 6 spm. CRU Type, Greenland; CRU 3208, male, 8mm, South East Greenland; CRU 3208, female, 9mm, South East Greenland. N 23433 female, 10mm, Laptev sea; N 23434 male, 12 mm, Laptev sea. SMNH 3509, M��ller bay. Novaja Semlya Exp, 1875, about 30 spm; SMNH 6669, 8 fvn, 70 �� 12 ��� 65 �� 45 ���, Kara sea, 1 spm; SMNH 6662, 1 spm; SMNH 6659, 1 spm. SMNH 6667, Novaja Semlya exp. 1875, 10 fvn, 73 �� 40 ��� 69 �� 10 ���, 10 fvn, 3 spm. SMNH 6664, 5 spm; SMNH 3502 female, 6.5mm, M��ller bay. Description (based upon N 23433 adult female, 10mm, and N 23434 adult male, 12 mm; both from Laptev sea. Zool.Inst. St.Petersburg. Det: O. turgidus.) Head and body: Head slightly longer than first pereonite. Cephalic lobe broadly triangular, distally acute; margins straight. Eyes yellow-brown in alcohol, oval, enlarged in adult male. Urosomite 1 with moderate dorsal depression. Antennae: Antenna 1 as long as head and the next two body segments; peduncle slightly longer than head, article 1 longer than broad, anterodorsal ���nose��� not conspicuous; accessory flagellum exceeds half the length of primary flagellum, 5 -articulate, article 1 as long as the rest of primary flagellum, longer than article 1 of primary flagellum; primary flagellum 11 -articulate, article 1 length equals next 3 articles, article 1 and article 2 primary flagellum with 2 slender robust setae distally; no calceoli on flagellum. Antenna 2 length about 1.3 times antenna 1; flagellum 19 -articulate; peduncle article 4 longer than article 5; no calceoli on flagellum. Both antennae longer, and with higher number of articles, in males than in females. Mouthparts: Epistome weakly convex; labrum straight, not in front of epistome, with 1 apical robust seta on each lobe. Mandibular incisors with convex margin; left lacinia mobilis present, right absent; accessory robust setae row present on left and right mandible, 3 long and slender robust setae; molar oval without visible triturating surface; palp article 1 longer than broad, article 2 longer than 3 with 11 to 13 distolateral setae (male with 21 setae), article 3 with 20���22 distolateral setae (male with 25). Maxilla 1 with 2 plumose setae on inner plate; outer plate with ST in a 7 / 4 -crown arrangement; palp large, 2 - articulate, 8 terminal robust setae and one simple seta present on distolateral corner; distomedial margin serrate. 8 Maxilliped inner plate with 3 nodular setae; inner and medial setae rows present, almost continuous with 8 plumose setae; outer plate subovate, without subapical notch, distal setae group with two robust setae, outer setae row with 12 marginal short robust setae, inner setae row present with 5 slender setae; palp 4 -articulate; article 2 slender; unguis present on dactylus. Pereopods: Pereopod 1 subchelate; coxa with 1 seta, rectangular with rounded corners, upper anterior margin straight, ventral margin weakly convex, posterior margin straight with a little notch and a small seta distally; basis long, slender, length> 2 times breadth, moderate setation along anterior margin; ischium posterior margin longer than breadth; merus as long as ischium; carpus longer than merus, as long as propodus; propodus rectangular, length 2.2 times breadth, margins subparallel; palm not clearly defined, oblique, convex and serrate, palm corner with 1 robust seta; dactylus as long as palm, accessory tooth present, cuticular teeth along posterior margin. Pereopod 2 subchelate; coxa rectangular with notch on posterodistal corner; ischium longer than merus; merus length 0.6 times carpus; propodus 0.6 to 0.7 times carpus, subrectangular, lateral margins slightly convex, distal margin slightly produced posterodistally; palm transverse; dactylus medial, shorter than palm, medium sized. Pereopod 3 coxa with notch at posterodistal corner; merus slightly expanded, without mediolateral setae row; propodus without setae row along anterior margin; dactylus long and slender. Pereopod 4 coxa anterior margin convex; weak posteroventral lobe. Pereopod 5 coxa asymmetrically bilobate, posterior lobe clearly produced ventrally; basis with anterior margin straight and with robust setae, expanded with posterior margin crenulate, convex, no submarginal robust setae-row; merus broad; propodus anterior margin with 4 paired robust setae and 2 apical robust setae; dactylus long and slender. Pereopod 6 coxa small, clearly lobate posteriorly; basis expanded posteriorly with crenulate margin, weakly convex, posteroventral corner rounded; merus broad; propodus slightly longer than propodus on pereopods 5 and 7, anterior margin with 4 paired robust setae and 2 apical robust setae; dactylus long and slender. Pereopod 7 basis expanded posteriorly with crenulate posterior margin, convex, posteroventral corner rounded; merus slightly expanded posterodistally; propodus anterior margin with 4 paired robust setae and 2 apical robust setae; dactylus short and slender. Gills on pereopods 2���6, with extra lobe on pereopods 5 and 6; oostegites on pereopods 2���5. Epimeral plates: Epimeral plate 1 anteroventral corner subangular, not produced, ventral margin straight, posteroventral corner subrounded. Epimeral plate 2 anteroventral corner rounded, ventral margin weakly convex, posteroventral corner angular with a small tooth, distal part of posterior margin straight. Epimeral plate 3 anteroventral corner rounded, ventral margin straight, posteroventral corner produced into a strong, slightly upturned and distally subacute tooth, posterior margin straight. Uropods: Uropod 1 peduncle longer than rami, outer margin with 9 robust setae, inner margin with 4 to 5 robust setae; rami subequal, outer ramus with 3 robust setae on outer margin; inner ramus with 3 robust setae on outer margin and 1 robust seta proximally on inner margin (absent in male). Uropod 2 peduncle shorter than rami, outer margin with 5 to 7 robust setae, inner margin with 1 apical robust seta; outer ramus shorter than inner, outer margin with 4 robust setae; inner ramus without constriction, outer margin with 1 robust seta; male with 3 robust setae on outer margin of each rami. Uropod 3 peduncle shorter than rami, with 2 medioapical robust setae and 1 apical robust seta on inner margin; outer ramus longer than inner ramus, 2 -articulate; rami without setae (male and female). Telson: Telson longer than broad, weakly convex and distally narrowing, cleft 30 %, incision deeper than broad, 2 dorsolateral setae and 2 apical setae present on each lobe. Distribution This is one of the more well-known species of Onisimus, with a wide holarctic distribution. Stephensen (1923) presented a distribution map covering the Atlantic distribution of the species; however, the localities in SW Norway and W. Sweden, noted by Sars (1890) are doubtful. We have checked the material from Haugesund, SW Norway, in the Oslo Museum, and the sample really contains O. plautus, but we greatly suspect some mix-up in the labelling. O. plautus has never been found in Norway since. Stappers (1911) recorded this species from N. Norway, with Sparre Schneider as a source, but this was an error (see Stephensen 1938, p. 37). The single old specimen from Bohusl��n was checked by Oldevig (1959) and likewise confirmed as O. plautus; again, the locality may well be incorrect. Onisimus plautus does occur, on the other hand, in W. Greenland (Stephensen 1923), in the Newfoundland-Nova Scotia area (Shoemaker 1930) as well as in the Gulf of St Lawrence (cf Brunel et al. 1998). O. plautus has been collected many places in the American Arctic (Shoemaker 1920, Stephensen 1944, Dunbar 1954, Oldevig 1959). Tzvetkova & Golikov (2001) report the species from the entire arctic coast line of Russia. In the Pacific the southernmost records seem to be in the Bering Strait (Gurjanova 1962). Onisimus plautus may therefore be said to have a true holarctic distribution, while further south it is clearly confined to cold waters. Biology Onisimus plautus is a common species many places, but it has almost never been collected from baited traps (a single specimen was reported by Legezynska (2001)), so maybe it is not a scavenger. Bryazgin (1987) collected the species in the Barents Sea at depths of 14���230m on various bottoms (clay, silt and stones), and the West Atlantic material of Shoemaker (1920) was likewise collected from sandy and muddy bottoms at depths of 100��� 250m. In fully Arctic waters the species may be found in more shallow water: Dunbar (1954) gave 10���70m from Ungava Bay, and most of the E. Greenland specimens were collected between 10���50m (Stephensen 1944). The species was nevertheless apparently absent in the shallow Chaun Bay area in the East Siberian Sea (Golikov & Tzvetkova 1994). We have been unable to check the very anomalous record by Sars (1886) of O. plautus collected from 1400m West of Bear Island. This species is parasitized by a podasconid isopod, probably of the genus Parapodascon (Vader, unpubl. data). The female is usually carrying from 4 to 7 eggs. Remarks Sars (1891) describes the eyes of living specimens as red. The description and figures given by Sars (1891) otherwise fit the examined specimens very well., Published as part of Berge, J��rgen, Vader, Wim & Johnsen, Jan Roger, 2007, Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Uristidae) II. The barentsi and edwardsii groups, pp. 55-68 in Zootaxa 1410 on pages 60-63, DOI: 10.5281/zenodo.175595, {"references":["Kroyer H. (1845) Karcinologiske Bidrag (Fortsaettelse). Naturhistorisk Tidsskrift, 453 - 638.","Oldevig, H. (1959) Arctic, Subarctic and Scandinavian amphipods in the collections of the Swedish Natural History Museum in Stockholm. Goteborgs Kungliga Vetenskaps- och Vitterhets-Samhalles Handlingar, Sjatte Foljden, Ser. B, band 8, nr 2, 1 - 132.","Brunel, P., Bosse, L. & Lamarche, G. (1998) Catalogue des Invertebres marins de l'estuaire et du golfe du Saint-Laurent. Publication Speciale Canadienne des Sciences Halieutiques et Aquatiques, 126, 1 - 405.","Stephensen. K. (1944). Amphipoda. The Zoology of East Greenland. Meddelelser om Gronland, 121 (14), 1 - 165.","Dunbar, M. J. (1954) The amphipod Crustacea of Ungava bay, Canadian Eastern Arctic. Journal of the Fisheries Research Board of Canada, 11, 709 - 798.","Tzvetkova, N. L. & Golikov, A. A. (2001) Amphipoda-Gammaridea. Pp 79 - 94 in B. I. Sirenko (ed.). List of species of free-living invertebrates of Eurasian Arctic seas and adjacent deep waters. Russian Academy of Sciences, Zoological institute. Explorations of the Fauna of the Seas 51, St. Petersburg.","Gurjanova, E. F. (1962). Bokoplavy severnoi chasti Tixogo Okeana (Amphipoda-Gammaridea), chast' 1. Akademiia Nauk SSSR, Opredeliteli po Fauna SSSR, 74, 1 - 440.","Legezynska, J. (2001). Distribution patterns and feeding strategies of lysianassoid amphipods in shallow waters of an Arctic fjord. Polish Polar Research, 22, 173 - 186","Golikov, A. A. & Tzvetkova, N. L. (1994) (Amphipoda (Amphipoda, Gammaridea) of the Chaun bay of the East Siberian Sea. Pp 211 - 249 in O. A. Scarlato (ed.) (Ecosystems and the flora and fauna of the Chaun bay of the East Siberian Sea.) Russian Academy of Sciences, Zoological Institute. Explorations of the Fauna of the Seas 47, St. Petersburg. (In Russian)","Sars, G. O. (1891) An account of the Crustacea of Norway, with short descriptions and figures of all the species. Vol. 1. Amphipoda part 5. Lysianassidae (concluded). Christiania & Copenhagen, Alb. Cammermeyers Forlag, pp 93 - 120."]}

Onisimus edwardsii (Kr��yer, 1846) Anonyx edwardsii Kr��yer 1846: 41 Onesimus Edwardsii Sars 1891: 105; Stephensen 1913: 121 Onisimus edwardsii Shoemaker 1930: 228; Lowry & Stoddart 1993: 173. Onisimus edwardsi Gurjanova 1951: 162 Boeckosimus edwardsii Barnard 1969: 330 Type locality 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, P 4 coxa with moderate posteroventral lobe. Telson cleft 30 %. Material examined USNM Acc.no 182783, Indian Harbor, Labrador, 1 spm. SMNH 6672 det: O. plautus, male, 9mm, Matoschkin scharr, Belusha viken, 6 spm. TMU xxx, Female, 10mm, Ekker��y 2���3m; TMU 1168, male, 8 mm, Vard��; 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. Norway and 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 1923 b). The most recent Norwegian catalogue (Vader et al. 1997) only has records from Troms�� (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 Russia East to the Chukchi Sea (Gurjanova 1985, Tzvetkova & Golikov 2001) and in the cold eastern waters of Canada (Shoemaker 1930, 1930 b, 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 edwardsii is 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. edwardsii is 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. caricus is 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���36m in E. Greenland, Dunbar (1954) from 5 to 20 m in Ungava Bay, and Weslawski (1990) from 2���20m in 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 1930 a, b)., Published as part of Berge, J��rgen, Vader, Wim & Johnsen, Jan Roger, 2007, Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Uristidae) II. The barentsi and edwardsii groups, pp. 55-68 in Zootaxa 1410 on pages 65-66, DOI: 10.5281/zenodo.175595, {"references":["Sars, G. O. (1891) An account of the Crustacea of Norway, with short descriptions and figures of all the species. Vol. 1. Amphipoda part 5. Lysianassidae (concluded). Christiania & Copenhagen, Alb. Cammermeyers Forlag, pp 93 - 120.","Stephensen K. (1913) Account of the Crustacea and the Pycnogonida collected by Dr. V. Nordmann in the summer of 1911 from Northern Stromfjord and Giesecke Lake in West Greenland. Meddelelser om Gronland, 51, 53 - 77.","Lowry, J. K. & Stoddart, H. E. (1993). The Onisimus problem (Amphipoda, Lysianassoidea, Uristidae). Zoologica Scripta, 22, 167 - 181.","Gurjanova, E. F. (1951). Bokoplavy morej SSSR i sopredel'nykh vod (Amphipoda-Gammaridea). Akademiia Nauk SSSR, Opredeliteli po Faune SSSR, 41, 1 - 1029.","Stephensen, K. (1923 b) Revideret Fortegnelse over Danmarks Arter af Amphipoda (1. Del). (Hyperiidea; Gammaridea: Lysianassidae). Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 76, 5 - 20.","Vader, W., Brattegard, T., Buhl Mortensen, L. & Miskov Larsen, K. (1997) Order Amphipoda, suborder Gammaridea. Pp 191 - 212 in T. Brattegard & T. Holthe (eds). Distribution of marine, benthic macro-organisms in Norway. A tabulated catalogue. Preliminary Edition. Utredning for DN 1997 - 1, 409 pp.","Gurjanova, E. F. (1985) (Bottom Crustacea, species of endemic genera Onisimus (Amphipoda) and Katianira (Isopoda) and deep-sea endemic species of Eurycope (Isopoda) and Gnathia (Gnathiidea).). P. 130 in Atlas Arktiki, Moskva 1985, 204 pp. (in Russian)","Tzvetkova, N. L. & Golikov, A. A. (2001) Amphipoda-Gammaridea. Pp 79 - 94 in B. I. Sirenko (ed.). List of species of free-living invertebrates of Eurasian Arctic seas and adjacent deep waters. Russian Academy of Sciences, Zoological institute. Explorations of the Fauna of the Seas 51, St. Petersburg.","Dunbar, M. J. (1954) The amphipod Crustacea of Ungava bay, Canadian Eastern Arctic. Journal of the Fisheries Research Board of Canada, 11, 709 - 798.","Brunel, P., Bosse, L. & Lamarche, G. (1998) Catalogue des Invertebres marins de l'estuaire et du golfe du Saint-Laurent. Publication Speciale Canadienne des Sciences Halieutiques et Aquatiques, 126, 1 - 405.","Shoemaker, C. R. (1955). Amphipoda collected at the Arctic Laboratory, Office of Naval Research, Point Barrow, Alaska, by G. E. MacGinitie. Smithsonian Miscellaneous Collections 128, 1 - 78.","Gurjanova, E. F. (1962). Bokoplavy severnoi chasti Tixogo Okeana (Amphipoda-Gammaridea), chast' 1. Akademiia Nauk SSSR, Opredeliteli po Fauna SSSR, 74, 1 - 440.","Legezynska, J. (2001). Distribution patterns and feeding strategies of lysianassoid amphipods in shallow waters of an Arctic fjord. Polish Polar Research, 22, 173 - 186","Weslawski, J. M. & Legezynska, J. (2002) Life cycles of some Arctic amphipods. Polish Polar Research, 23, 253 - 264.","Stephensen. K. (1944). Amphipoda. The Zoology of East Greenland. Meddelelser om Gronland, 121 (14), 1 - 165.","Weslawski, J. M. (1990) Distribution and ecology of South Spitsbergen coastal marine Amphipoda (Crustacea). Polskie Archiwum Hydrobiologii, 37, 503 - 519.","Legezynska, J., M. Weslawski, J. & Presler, P. (2000) Benthic scavengers collected by baited traps in the high Arctic. Polar Biology, 23, 539 - 544.","Shoemaker, C. R. (1930 a) The Amphipoda of the Cheticamp Expedition of 1917. Contributions to Canadian Biology and Fisheries, 5 (1929), 221 - 359.","Shoemaker, C. R. (1930 b) The lysianassid amphipod crustaceans of Newfoundland, Nova Scotia, and New Brunswick in the United States National Museum. Proceedings of the United States National Museum, 77, art. 4, 1 - 19."]}