Tryphosella rodondo, Lowry & Stoddart, 2011

Lowry, J. K. & Stoddart, H. E., 2011, The tryphosine genera Photosella gen. nov. and Tryphosella Bonnier, 1893 (Crustacea: Amphipoda: Lysianassoidea: Lysianassidae: Tryphosinae) in Australian waters 2956, Zootaxa 2956 (1), pp. 1-76 : 50-52

Tryphosella rodondo sp. nov.

( Figs 33–36 )

Tryphosella sp. 91. — Lowry & Smith, 2003: 56.

Type material. HOLOTYPE, female, with setose oostegites, 5.0 mm, MV J62300 , 66 km south of Rodondo Island , Victoria, central Bass Strait, Australia, 39°48.6'S 146°18.8'E, 82 m, sand, silt and mud, epibenthic sled, 13 November 1981, R. Wilson, RV Tangaroa , stn BSS-158S . PARATYPES: 1 female, 5.0 mm, AM P.85307, same data as Holotype ; 7 specimens, P.45777, east of Fortescue Bay , north of Hippolyte Rocks, Tasmania, Australia, 43°06.70'S 148°03.45'E, 100 m, baited trap, 15.8°C, 16–17 April 1993, J.K. Lowry & P. Freewater, MV Tasmanian Enterprise, stn TAS-353 ; 20 specimens, AM P.50280, 1 ovigerous female, 5.5 mm, AM P.71624 , 1 immature female, 4.0 mm, AM P.71625, 1 mature male, 5.0 mm, AM P.71625 and 1 immature male, 4.2 mm, AM P.71626, same data, stn TAS-354 ; 200 specimens, AM P.51834 and 45 specimens, MV J62310 , same data, 17–18 April 1993, stn TAS-371 ; 11 specimens, AM P.51835, east of Fortescue Bay , north of Hippolyte Rocks, Tasmania, 43°06.70'S 148°3.45'E, 100 m, baited trap, 15.6°C, 8–9 April 1994, J.K. Lowry & K. Dempsey, MV Martrudan, stn TAS-389 ; 1 specimen, AM P.51836, same data, stn TAS-390 ; 39 specimens, AM P.51837, same data, stn TAS- 391 ; 38 specimens, AM P.51842, same data, 9–10 April 1994, stn TAS-408 ; 4 specimens, AM P.51319, same data, stn TAS-409 .

Additional material examined. Tasmania: 2 specimens, AM P.51838, east of Fortescue Bay, 43°06.70'S 145°13.6'E, 200 m, baited trap, 13.2° C, J.K. Lowry & K. Dempsey, MV Martrudan, 8–9 April 1994, stn TAS-392; 13 specimens, AM P.51833, east of Fortescue Bay, 43°09.37'S 14513.6'E, 300 m, baited trap, 14.2°C, 16–17 April 1993, J.K. Lowry & P. Freewater, MV Tasmanian Enterprise, stn TAS-359; 2 specimens, AM P.51839, east of Fortescue Bay , 43°09.37'S 145°13.6'E, 300 m, baited trap, 11.0° C, J.K. Lowry & K. Dempsey, MV Martrudan, 8– 9 April 1994, stn TAS-397; 4 specimens, AM P.51843, same data, 9–10 April 1994, stn TAS-414; 3 specimens, AM P.51840 and 1 specimen, AM P71631, same data, stn TAS-399; 2 specimens, AM P.51841, east of Fortescue Bay , 43°07.36'S 145°13.75'E, 400 m, baited trap, 10.0° C, J.K. Lowry & K. Dempsey, MV Martrudan, 8–9 April 1994, stn TAS-400; 1 specimen, AM P.51844, same data, 9–10 April 1994, stn TAS-418; many specimens, AM P.74784, Hill U, south-southeast of South East Cape, 44°19'30"S 147°10'48"E, 1155 m, baited trap, 27 January 1997, CSIRO Seamount Survey, RV Southern Surveyor, stn SS01/97/39; 1 specimen, AM P.74785, Hill U, 82.8 km south-southeast of South East Cape, 44°19'12"S 147°07'12"E, 1083 m, baited trap, 28 January 1997, CSIRO Seamount Survey, RV Southern Surveyor, stn SS01/97/41; many specimens, AM P.74786, Hill V, south-southeast of South East Cape, 44°23'36"S 147°10'42"E, 1400 m, baited trap, 30 January 1997, CSIRO Seamount Survey, RV Southern Surveyor, stn SS01/97/61; 15 specimens, AM P.74786, Hill D1, south-southeast of South East Cape, 44°23'24"S 147°16'12"E, 1942 m, baited trap, 31 January 1997, CSIRO Seamount Survey, RV Southern Surveyor , stn SS01/97/65 .

Type locality. 66 km south of Rodondo Island , Victoria, central Bass Strait, Australia, 39°48.6'S 146°18.8'E, 82 m depth .

Etymology. The species is named for its type locality.

Diagnostic description. Head lateral cephalic lobe rounded, apically rounded; eyes reniform. Antenna 1 peduncular article 1 without anterodistal lobe; article 2 without anterodistal lobe; accessory flagellum present, not forming cap, 3-articulate, 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 4 and 5 not enlarged; flagellum short, calceoli absent. Epistome/Upper lip separate; epistome produced beyond upper lip, broadly rounded; upper lip slightly produced, straight. Mandible molar with asymmetrically reduced column, proximally setose, distally triturating; palp attached about midway, article 3 with proximal A3-seta. Maxilla 1 outer plate setal-tooth 7 present, setal-tooth 7, left and right asymmetrical, left cuspidate along most of sinusoidal inner margin, right cuspidate along most of curved inner margin; palp distal margin with apical robust setae. Maxilliped basis without recurved hook; outer plate with 2 long apical robust setae.

Gnathopod 1 subchelate; coxa small (length 1.3 x breadth), subtriangular, tapering distally; basis densely setose along anterior margin; ischium short; carpus long, longer than propodus, without posterior lobe; propodus small, margins subparallel, sparsely setose along posterior margin, palm slightly acute, entire, straight. Gnathopod 2 palm transverse. Pereopod 4 coxa without distinct lateral ridge, with a well-developed posteroventral lobe. Pereopod 5 coxa without distinct lateral ridge, without umbo; basis about as long as broad, not posteroproximally excavate, posterior margin weakly serrate. 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 acutely produced. Urosomite 1 not projecting over urosomite 2, with anterodorsal notch and slightly rounded boss. Uropods 1 and 2 outer rami without stout striated robust setae. Uropod 2 inner ramus without constriction. Uropod 3 peduncle without dorsolateral flange, with 3 short apicomedial robust setae; inner and outer rami well developed, outer ramus article 2 short, without plumose setae on rami. Telson moderately cleft, with dorsal robust setae, with 1 apical robust seta on each lobe.

Male (sexually dimorphic characters). Head lateral cephalic lobe subtriangular, apically subacute. Antenna 1 calceoli present, small. Antenna 2 flagellum long, calceoli present. Uropod 3 with plumose setae on both rami.

Remarks. Tryphosella rodondo and T. chinchilla both have gnathopod 1 with a significantly reduced coxa and a densely setose anterior margin on the basis. In T. rodondo there are no robust setae on the proximal articles of the flagellum of antenna 1 (present in T. chinchilla ) and a moderately cleft telson (deeply cleft in T. chinchilla ). See also Remarks for T. chinchilla .

Although T. rodondo was trapped frequently in low numbers (up to 245 specimens in a trap) along the east coast of Tasmania in depths between 100 and 400 m, it was most common on sea mounts south of Tasmania in depths between 1000 and 2000 m.

Distribution. Tasmania, southern Australia; 82–1942 m depth.

Figures

FIGURE 33. Tryphosella rodondo sp. nov. Paratype, female, 5.0 mm, AM P.85307, south of Rodondo Island, Victoria, central Bass Strait.

FIGURE 34. Tryphosella rodondo sp. nov. Holotype, female, 5.0 mm, MV J62300; south of Rodondo Island, Victoria, central Bass Strait; paratype, male, 5.0 mm, AM P.71625, east of Fortescue Bay, Tasmania. Scales represent 0.1 mm.

FIGURE 35. Tryphosella rodondo sp. nov. Holotype, female, 5.0 mm, MV J62300, south of Rodondo Island, Victoria, central Bass Strait. Scales represent 0.2 mm.

FIGURE 36. Tryphosella rodondo sp. nov. Holotype, female, 5.0 mm, MV J62300, south of Rodondo Island, Victoria, central Bass Strait; paratype, male, 5.0 mm, AM P.71625, east of Fortescue Bay, Tasmania. Scales represent 0.1 mm.