Sophrosyne peartae, Lowry & Stoddart, 2010

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 : 25-26

Sophrosyne peartae sp. nov.

( Figs 14–16 )

Type material. HOLOTYPE, female, 4.6 mm, ovigerous (3 eggs), MV J60733 , south of Point Hicks , Victoria, Australia (38°19.10'S 149°14.30'E), 600 m, coarse sand, epibenthic sled, M.F. Gomon on RV Franklin, 24 July 1986 (stn SLOPE 39).

Type locality. South of Point Hicks , Victoria, Australia (38°19.10'S 149°14.30'E), 600 m.

Etymology. This species is named for Rachael Peart, who illustrated many of our amphipods and found morphological characters we had not noticed.

Diagnostic description. Head lateral cephalic lobe small, narrowly rounded; eyes oval. Antenna 1 peduncular article 1 short, length 1.4 x breadth; accessory flagellum long, 0.5 x primary flagellum, article 1 short, 0.9 x article 2; flagellum 7-articulate, without callynophore. Antenna 2 peduncular article 3 0.5 x article 4; flagellum 7-articulate. Mandible incisors with straight margins; palp article 2 slender, 1 x article 3, with 1 submarginal posterodistal A2-seta, without D2-setae, article 3 length 6.2 x breadth, without D3-setae, and/ with 4 apical E3-setae. Maxilla 1 outer plate with setal-teeth in a 2/4 arrangement. Maxilliped inner plate subrectangular, without apical nodular robust setae; outer plate submarginal setae long, simple; palp article 2 slender, length 2.2 x breadth, 1.1 x article 3, article 3 slender, length 2.5 x breadth, dactylus with unguis absent. Gnathopod 1 basis length 1.7 x breadth, anterior margin with slender setae; ischium length 1.4 x breadth; merus, posterior margin lined with long slender setae; carpus length 0.5 x propodus; propodus length 1.8 x breadth, posterior margin slightly concave, with robust setae, palm margin sinusoidal, posterodistal corner with produced subacute spine bearing vestigial seta. Gnathopod 2 grossly subchelate in female, [not known for male]; ischium length 2.9 x breadth; carpus long, length 2.4 x breadth, posterior margin broadly lobate; propodus subrectangular, short, length 1.8 x breadth; palm acute, with large, concave, smooth margin. Pereopod 3 merus not expanded anteriorly. Pereopod 4 merus not expanded anteriorly. 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 almost straight, scalloped, posteroventral margin straight, posteroventral lobe not extending beyond ischium; merus not expanded posteriorly; propodus with setae along anterior margin. Epimeron 3 posterior margin with strong upturned spine above rounded posteroventral corner. Urosomite 1 with anterodorsal notch and rounded boss, with lateral flange. Uropod 1 outer ramus slightly longer than inner ramus; outer ramus with 2 dorsal robust setae; inner ramus without dorsal robust setae. Uropod 2 rami subequal in length; rami without robust setae. Uropod 3 peduncle length 1.5 x breadth. Telson longer than broad, length 1.2 x breadth, moderately cleft (50%), distal margins rounded, with1 apical slender seta on each lobe.

Remarks. Only two species of Sophrosyne , S. peartae and S. murrayi , have a grossly expanded palm on gnathopod 2. They differ most noticeably in the shape of the propodus of gnathopod 2, (subquadrate in S. murrayi and subrectangular in S. peartae ) and in the posteroventral corner of epimeron 3 (subquadrate in S. murrayi and rounded in S. peartae ).

Distribution. Slope off Bass Strait, Australia in 600 m depth.

Figures

FIGURE 14. Sophrosyne peartae sp. nov., holotype female, 4.6 mm, MV J60733, south of Point Hicks, Australia.

FIGURE 15. Sophrosyne peartae sp. nov., holotype female, 4.6 mm, MV J60733, south of Point Hicks, Australia. Scales represent 0.1 mm.

FIGURE 16. Sophrosyne peartae sp. nov., holotype female, 4.6 mm, MV J60733, south of Point Hicks, Australia. Scales represent 0.2 mm.