"Species namea Location Reference";"Sex TL";Antennule;"Swimming legs setationb";Urosome;P1;P2;P4 "O. helgolandica Helgoland (North Sea) (Claus 1863)";"F 0.75";"“Hardly reaching the end of thorax”";nd;nd;nd;"Ur4 shorter than Ur3 and almost as long as Fu. Fu with short setae" "O. similis Nice (Mediterranean Sea) (Claus 1866)";"F ~1.0";"“Nearly reaching the base of the urosome”";nd;nd;nd;"Fu with short colorless setae" "O. spinifrons Boeck, 1864 ? O. helgolandica Claus, 1863 (Brady 1878)";"F 0.85";"“About as long as the cephalothorax”";nd;nd;nd;"Ur1 long, Ur2 and Ur4 about equal and of moderate length, Ur3 somewhat shorter. Fu shorter than any Ur segment" "O. similis Claus Naples (Mediterranean Sea) (Giesbrecht 1893)";"F 0.73–0.80";"“Barely to the genital openings”";"(0,1,4;1,1,2)/ (1,1,5;0,0,1)";"(0,1,5;1,0,1)/ (1,2,5;0,0,1)";"(0,1,5;0,0,0)/ (1,2,4;0,0,1)";"Ur & Fu relative lengths: 5,12,5,4,5,3.5. CR 2.5 width" "M 0.51–0.61";Geniculate;"(0,1,4;1,1,2)/ (nd)";"(0,1,4;1,1,2)/ (nd)";"(0,1,4;1,1,2)/(nd)";nd "O. similis Claus, 1866 Christmas Islands (Indian Ocean) (Farran 1913)";"F 0.73–0.80";nd;"(nd;1,1,2)/ (nd)";"(nd;1,0,1)/ (nd)";(nd);nd "O. helgolandica Claus, 1863 off Norway (Sars 1913–1918)";"F 0.70–0.90";"“Extending scarcely beyond the anterior division of the body. Length 1.02 times prosome*";"(0,1,4;1,1,2)/ (1,6;0,1)";"(0,1,5;1,0,1)/ (1,2,5;0,0,1)";"(0,1,5;0,0,1?)/ (1,2,4;0,0,1)";"Ur & Fu relative lengths: 5,13,5.5,5.5,4.5,4*. CR hardly shorter than Ur4" "M 0.50–0.60";Geniculate;"(nd;1,1,2)/(nd)";"(0,1,5;1,1,2)/ (1,2,5;0,0,1)";"(nd;1,1,2)/(nd)";nd "O. similis Claus Valdivia (SE Pacific) (Rosendorn 1917)";"F 0.78";"“Hardly extending to the genital openings”";"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,0,1)/ (nd)";"(0,1,5;0,0,1)/ (nd)";nd "M 0.67";Geniculate;"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";nd "O. helgolandica Claus [= O. similis Claus] Adriatic Sea (Pesta 1920)";"F 0.73–0.96";"“Barely reaching the genital openings”";"(nd;1,1,2)/(nd)";"(nd;1,0,1)/(nd)";"(nd;0,0,0)/(nd)";"Fu shorter than Ur4" "M 0.59–0.70";nd;"(nd;0,0,2)/(nd)";"(nd;0,0,2)/(nd)";"(nd;0,0,2)/(nd)"; "O. similis Claus ?1863 O. helgolandica Various localities (Kiefer 1929)";"F 0.74–0.95";"“Reaching the genital openings, located a little before the middle of the genital segment”";"(nd;1,1,2)/(nd)";"(nd;1,0,1)/(nd)";"(nd;0,0,1)/(nd)";nd "M 0.60–0.70";nd;"(nd;1,1,2)/(nd)";"(nd;1,1,2)/(nd)";"(nd;1,1,2)/(nd)";nd "O. helgolandica Claus, 1863 (O. similis Claus,1863) Various localities (Rose 1933)";"F 0.73–0.96";"“Barely attains the genital openings”";"(nd;1,1,2)/(nd)";"(0,1,5;1,0,1)/(nd)";"(nd;0,0,0)/(nd)";"Fu shorter than Ur4. CR twice width" "M 0.59–0.70";nd;nd;"(0,1,5;1,1,2)/(nd)";nd;nd "O. similis Claus, 1866 Japan (Mori 1937)";"F 0.80";"“Reach to the genital pores”";"(0,1,4;1,1,2)/(nd)";"(0,1,5;1,0,1)/(nd)";"(0,1,5;0,0,1)/(nd)";"Fu more than twice width. CR equal width" "M 0.65";Geniculate;"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";nd "O. helgolandica Claus, 1863 NE Pacific (Davis 1949)";"F 0.69–0.96";"“Barely reach to genital segment”";"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,0,1)/(nd)";"(0,1,5;0,0,1)/(nd)";"Ur 0.75 prosome length. CR shorter than Ur4" "M 0.50–0.70";Geniculate;"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";nd "O. helgolandica Claus Messina Strait (Mediterranean Sea) (Crisafi 1959)";"F 0.78";nd;"(0,1,4;1,1,2)/(nd)";"(0,1,5;1,0,1)/(nd)";"(0,1,5;0,0,1)/(nd)";nd "M 0.68";"Non geniculate§";"(0,1,4;1,1,2)/(nd)";"(0,1,5;1,0,1)/(nd)";"(0,1,5;0,0,1)/(nd)";nd "O. helgolandica Claus, 1863 Buenos Aires shelf (Argentine Sea) (Ramírez 1966)";"F 0.80";"“Reaches the genital openings”";"(0,1,4;1,1,2)/(nd)";"(0,1,5;1,0,1)/(nd)";"(0,1,5;0,0,1)/(nd)";"Ur1 2.5 width. Ur4 similar to Ur2 and Ur3. Fu slightly shorter than Ur4. CR twice width" "O. similis Claus, 1866 Río Deseado estuary (Argentine Sea) (Pallares 1968)";"F 0.89–1.10";nd;"(nd;1,1,2)/(nd)";"(nd;1,0,1)/(nd)";"(nd;0,0,1)/(nd)";"CR divergent" "M 0.50–0.67";Geniculate;nd;nd;nd;nd "O. helgolandica sensu Sars, 1913 Gulf of Lion (Mediterranean Sea) (Razouls 1972)";"F nd";nd;nd;"(0,1,5;1,0,1)/ (1,2,5;0,0,1)";"(0,1,5;0,0,0)/ (1,2,4;0,0,1)";nd "M nd";nd;"(0,1,3;1,1,2)/ (1,1,5;0,0,1)";"(0,1,5;1,1,2)/ (1,2,5;0,0,1)";"(0,1,5;1,1,2)/ (1,2,4;0,0,1)";nd "O. similis Claus, 1866 Suruga Bay (Japan) (Nishida et al. 1977)";"F 0.69–0.84";"“Extending to the end of thorax 5”";"(0,1,4;1,1,2)/ (1,1,5;0,0,1)";"(1,0,5;1,0,1)/ (1,2,5;0,0,1)";"(0,1,5;0,0,1)/ (1,2,4;0,0,1)";nd "M 0.60–0.65";nd;"(0,1,4/5;1,1,2)/ (nd)";"(0,1,5;1,1,2)/(nd)";"(0,1,5;1,1,2)/(nd)";nd "O. similis Claus, 1866 ? O. helgolandica Claus, 1863 Various localities (Shuvalov 1980)";"F 0.78";nd;"(0,1,4;1,1,2)/ (1,1,5;0,0,1)";"(0,1,5;1,0,1)/(nd)";"(nd;0,0,1)/(nd)";nd "M 0.60–0.70";nd;nd;nd;nd;nd "O. similis Claus, 1866 (SW Atlantic) (Björnberg 1981)";"F nd";"Extending slightly beyond thorax 5*";nd;nd;nd;nd "M 0.70";nd;"(nd;1,1,2)/(nd)";"(nd;1,1,2)/(nd)";"(nd;1,1,2)/(nd)";nd "O. similis Claus, 1866 Various localities (Nishida 1985)";"F 0.68–0.96";"“Length 1.1–1.3 times prosome”";"(0,1,4;1,1,2)/ (1,1,5;0,0,1)";"(0,1,5;1,0,1)/ (0/1,1/2,5;0,0,1)";"(0,1,5;0,0,1)/ (1,2,4;0,0,1)";"Ur & Fu relative lengths: 13,34,15,14,14,11. Ur4 1.1–1.3 width. CR 1.9–2.4 width" "O. similis Claus, 1866 Magallanes Strait (Argentina-Chile) (Mazzochi et al. 1995)";"F 0.80–0.92";nd;"(0,1,4;1,1,2)/ (1,1,5;0,0,1)";"(0,1,5;1,0,1)/ (1,2,5;0,0,1)";"(0,1,5;0,0,1)/ (1,2,4;0,0,1)";"Ur & Fu relative lengths: 15,36,14,12,12,11" "O. aff. helgolandica sensu Sars, 1913 Buenos Aires and southern Patagonian shelves (Argentine Sea) (Our unpublished data)";F;"Extending to the genital openings. Length 1.1-times prosome.";"(0,1,4;1,1,2)/ (1,6;0,1)";"(0,1,5;1,0,1)/ (1,2,5;0,0,1)";"(0,1,5;0,0,1)/ (1,2,4;0,0,1)";"Ur & Fu relative lengths: 13.5,34,16,14,13,10.5. Ur1 2.0–2.2 width. CR twice width" M;Geniculate;"(0,1,4;1,1,2)/nd";"(0,1,5;1,1,2)/nd";"(0,1,5;1,1,2)/nd";nd