Sophrosyne robertsoni Stebbing & Robertson, 1891

Lowry, J. K. & Stoddart, H. E., 2010, Sophrosynidae, a new family in the Lysianassoidea (Crustacea: Amphipoda) with a revision of the genus Sophrosyne, Zootaxa 2370 (1), pp. 1-35 : 26-29

Sophrosyne robertsoni Stebbing & Robertson, 1891

Sophrosyne robertsoni Stebbing & Robertson, 1891: 31 , pl. 5A. — Robertson, 1892: 203. — Della Valle, 1893: 795. — Stebbing, 1906: 21. —J.L. Barnard, 1958: 99. — Moore, 1984: 37 (in part, part = S. inverarae , part = S. moorei ). — Barnard & Karaman, 1991: 533.

? Sophrosyne robertsoni . — Norman, 1900: 196 (maybe in part, part = S. inverarae ). — Palerud & Vader, 1991: 43 (maybe in part). — Kilgallen et al., 2007: 1243 (maybe in part, part = S. inverarae ).

not Sophrosyne robertsoni . —J.L. Barnard, 1966: 72, figs 21, 22 (= Sophrosyne californica ).

not Sophrosyne robertsoni . — Lincoln, 1979: 52, fig. 17 (= S. inverarae ). — Moore, 1983: 103, figs 1–3 (= S. moorei ).

Material. No material available. Description based on text and figures of Stebbing & Robertson (1891), an ovigerous female specimen, approximately 6 mm.

Type locality. Clyde Sea , western Scotland (approx. 55°42'N 5°W) .

Diagnostic description. Head [lateral cephalic lobe not known]; eyes apparently absent. Antenna 1 peduncular article 1 medium length, length 1.6 x breadth; accessory flagellum medium length, 0.5 x primary flagellum, article 1 short, 1 x article 2; flagellum 6-articulate, without callynophore. Antenna 2 peduncular article 3 0.5 x article 4; flagellum 8-articulate. Mandible incisors with straight margins; palp article 2 slender, 1 x article 3, with 1 submarginal posterodistal A2-setae, without D2-setae, article 3 length 8 x breadth, with 2 D3-setae along most of posterior margin and 3 apical E3-setae. Maxilla 1 outer plate with setal-teeth in a 2/0 arrangement. Maxilla 2 inner plate narrow, outer plate broader; inner plate length 0.64 x outer plate. Maxilliped inner plate subovate, without apical nodular robust setae; outer plate submarginal setae short, simple; palp article 2 slender, length 2.4 x breadth, 1 x article 3, article 3 slender, length 2.8 x breadth, dactylus with unguis absent. Gnathopod 1 basis length 1.9 x breadth, anterior margin with slender setae; ischium length 1.25 x breadth; merus, posterior margin lined with long slender setae; carpus length 0.6 x propodus; propodus length 1.7 x breadth, posterior margin slightly concave, with robust setae, palm margin convex, posterodistal corner with produced subacute spine without seta. Gnathopod 2 minutely subchelate; ischium length 2.9 x breadth; carpus long, length 3.6 x breadth, posterior margin straight; propodus subrectangular, long, length 2.3 x breadth; palm acute, with convex, serrate margin. Pereopod 4 merus expanded anterodistally along carpus. Pereopod 5 basis moderately expanded posteriorly; merus slightly expanded posteriorly. Pereopod 6 coxa small, slightly lobate posteriorly; merus slightly expanded posteriorly. Pereopod 7 basis posterior margin slightly rounded, minutely crenate, posteroventral margin rounded, posteroventral lobe not extending beyond ischium; merus slightly expanded posteriorly; propodus without setae along anterior margin. Epimeron 3 posterior margin with strong upturned spine above rounded posteroventral corner. Urosomite 1 with rounded boss, without lateral flange. Uropod 1 rami subequal in length; outer ramus with 3 dorsal robust setae; inner ramus with 1 dorsal robust seta. Uropod 2 rami subequal in length; outer ramus with robust setae. Uropod 3 [peduncle not known]; rami subequal in length. Telson longer than broad, length 1.3 x breadth, moderately cleft (38%), distal margins incised, with 1 apical slender setae on each lobe.

Remarks. Sophrosyne robertsoni belongs to the group of species with a curved posteroventral corner on epimeron 3. It is the only species in the group without a seta on the posterodistal corner of the palm of gnathopod 1. Its telson is also much less cleft (38%) than other members of the group.

Distribution. Clyde Sea, western Scotland.