Pseudonesimus robustus (J.L. Barnard, 1961 ) Kilgallen & Lowry, 2014

Kilgallen, N. M. & Lowry, J. K., 2014, The Tryphosa group (Crustacea: Amphipoda: Lysianassoidea: Lysianassidae: Tryphosinae), Zootaxa 3768 (5), pp. 501-545 : 513-516

Pseudonesimus robustus (J.L. Barnard, 1961) comb. nov.

( Figs 6–8 )

Ambasiopsis robustus J.L. Barnard, 1961: 30 , fig. 1.

Schisturella robusta .―J.L. Barnard, 1966: 71 (key).― Barnard & Karaman, 1991: 527.― Larsen, 2007: 14 (key).

Schisturella robusta robusta .―J.L. Barnard, 1967: 72 (key).― Barnard & Ingram, 1990: 31 (key).― Barnard & Karaman, 1991: 527.― Hendrycks & Conlan, 2003: 2333 , fig. 13.

Types. Holotype, male, 10 mm, ZMUC CRU-1976 .

Type locality. Off Fiordland , South Island, New Zealand (44º18'S 166º46'E), clay, 3580 m depth .

Material examined. 1 female, 9.0 mm, NMV J46957 , from off Freycinet Peninsula , Tasmania, Australia (42°0.20'S 148°37.70'E), 720 m, coarse shelly sand, WHOI epibenthic sled, 27 July 1986, M.F. Gomon et al, RV Franklin stn slope 46 ; 6 specimens, NMV J46958 , from off Freycinet Peninsula , Tasmania, Australia (42°0.20'S 148°37.70'E), 720 m, coarse shelly sand, WHOI epibenthic sled, 27 July 1986, M.F. Gomon et al., RV Franklin stn slope 46 ; 4 specimens, NMV J46959 , from off Freycinet Peninsula , Tasmania, Australia (42°2.20'S 148°38.70'E), 800 m, coarse shelly sand, WHOI epibenthic sled, 27 July 1986, M.F. Gomon et al, RV Franklin stn slope 45 ; 1 specimen, NMV J46960 , from off Freycinet Peninsula , Tasmania, Australia (42°2.20'S 148°38.70'E), 800 m, coarse shelly sand, WHOI epibenthic sled, 27 July 1986, M.F. Gomon et al, RV Franklin stn slope 45 .

Description. Based on female, 9.0 mm, NMV J46957 . Head lateral cephalic lobe subtriangular, apically subacute; eyes apparently absent. Antenna 1 peduncular article 1 without anterodistal lobe; article 2 without anterodistal lobe; accessory flagellum present, forming cap partially covering callynophore, terminal article not offset; flagellum with strong 2-field callynophore, robust setae absent from proximal articles; calceoli absent. Antenna 2 peduncular article 3 short, articles 3 to 5 not enlarged, articles 4–5 with brush setae on the anterior margin; flagellum short, calceoli absent. Epistome/upper lip separate; epistome less produced than upper lip, straight; upper lip produced, rounded apically. Mandible molar with reduced column and convex strongly triturating surface. Maxilla 1 outer plate setal-tooth 7 present, left and right symmetrical, not cuspidate; palp distal margin with apical robust setae. Maxilliped basis without recurved hook; outer plate with 2 long, broad apical robust setae.

Pereonites 1–7 dorsally smooth. Gnathopod 1 slightly chelate; coxa reduced, significantly shorter than coxa 2, subquadrate; basis moderately setose along anterior margin; ischium short; carpus short, subequal in length to propodus, without posterior lobe; propodus small, sparsely setose along posterior margin, slightly obtuse, entire, straight. Gnathopod 2 propodus palm transverse. Pereopod 4 coxa without distinct lateral ridge. Pereopod 5 coxa without distinct lateral ridge, without umbo; basis longer than broad, without photophore, not posteroproximally excavate, posterior margin not serrate, posterior margin without mid-central spine, without posteroventral lobe or spine. Pereopod 7 basis posterodistally produced less than halfway along merus, not posterodistally excavate.

Pleonites 1–3 without mid-dorsal carina, not produced dorsodistally. Epimeron 3 posterior margin smooth, posteroventral corner narrowly rounded. Urosomite 1 n ot projecting over urosomite 2, dorsally straight. Uropod 2 inner ramus with constriction. Uropod 3 stout; peduncle without dorsolateral flange; inner and outer rami well developed, outer ramus article 2 short, without plumose setae on rami. Telson moderately cleft, with dorsal robust setae per lobe, with 2 tiny apical robust setae on each lobe.

Sexually dimorphic characters. None known.

Depth range. 720–3580 m (J.L. Barnard 1961; this study).

Remarks. This is the first record of this species in Australian waters. It has previously been recorded from the west coast of the New Zealand South Island.

Distribution. South Pacific Ocean. Tasman Sea: southwest coast of New Zealand (J.L. Barnard 1961); east coast of Tasmania (this study).

Figures

FIGURE 6. Pseudonesimus robustus (J.L. Barnard, 1961), female habitus, 9.0 mm, NMV J46957.

FIGURE 7. Pseudonesimus robustus (J.L. Barnard, 1961), female, 9.0 mm, NMV J46957, from off the Freycinet Peninsula, Tasmania, Australia. Scale bars: 0.2 mm.

FIGURE 8. Pseudonesimus robustus (J.L. Barnard, 1961), female, 9.0 mm, NMV J46957, from off the Freycinet Peninsula, Tasmania, Australia. Scale bars: 0.2 mm.