Tryphosella freycinet, 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 : 42-45

Tryphosella freycinet sp. nov.

( Figs 27–29 )

Tryphosella sp. 188. — Lowry & Smith, 2003: 56.

Type material. HOLOTYPE, female, ovigerous (4 eggs), 5.0 mm, AM P.69467, 50 m off Weatherhead , Freycinet Peninsula, Tasmania, Australia, 42°14'S 148°15'E, 13 m, baited trap, 30 April–1 May 1991, J.K. Lowry & S.J. Keable, RV Flying Scud, stn TAS-339 . PARATYPES: 1 male, 4.5 mm, AM P.69468; 1 male, 4.0 mm, AM P.69469; 114 specimens, AM P.69470; all with same data as Holotype .

Additional material examined. Tasmania: 1 female, AM P.69466, about 100 m west of Turners Rock and 80 m offshore, north side of Cape Sorell , 42°11.5'S 145°10.8'E, 13 m, baited trap, probably rocky bottom with sand patches, 27–28 April 1991, J.K. Lowry & S.J. Keable , RV Flying Scud , stn TAS-301 ; 12 specimens, AM P.69471, off rocky point near eastern end of Bryans Beach, Freycinet Peninsula , 42°16'S 148°17.4'E, 12 m, baited trap, probably sandy bottom, 30 April–1 May 1991, J.K. Lowry & S.J. Keable , RV Flying Scud , stn TAS-338 ; 1 male, AM P.52148, mouth of Fortescue Bay , 43°07.77'S 145°59.47'E, 50 m, baited trap, 16.6°C, 8–9 April 1994, J.K. Lowry & K. Dempsey , MV Martrudan , stn TAS-387

Type locality. 50 m off Weatherhead , Freycinet Peninsula, Tasmania, Australia, 42°14'S 148°15'E, 13 m depth .

Etymology. The species is named for its type locality.

Diagnostic description. Head lateral cephalic lobe a semidome, apically rounded; eyes apparently absent. Antenna 1 peduncular articles 1 and 2 without anterodistal lobe; accessory flagellum not forming cap, 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, narrowly 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 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 1 short apicolateral robust seta and 3 short apical robust setae.

Gnathopod 1 subchelate; coxa small (length 1.2 x breadth), subtriangular, tapering distally; basis sparsely setose along anterior margin; ischium short; carpus long, subequal in length to propodus, without posterior lobe; propodus small, margins subparallel, sparsely setose along posterior margin, palm transverse, entire, straight. Gnathopod 2 palm moderately obtuse. 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 not 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 narrowly rounded. Urosomite 1 not projecting over urosomite 2, with wedge-shaped boss,

obliquely truncated apically. Uropods 1 and 2 outer rami with all robust setae stout and striated. Uropod 2 inner ramus without constriction. Uropod 3 peduncle without dorsolateral flange, with 1 short apicomedial robust seta; inner and outer rami well developed, outer ramus article 2 short, without plumose setae on rami. Telson deeply cleft, with dorsal robust setae, with 1 apical robust seta on each lobe.

Male (sexually dimorphic characters). Head lateral cephalic lobe rounded. Antenna 1 calceoli present, small. Antenna 2 flagellum long, calceoli present. Epimeron 3 posteroventral corner subquadrate. Urosomite 1 with deep notch and subtriangular, subacute boss. Uropod 3 with few plumose setae on each ramus.

Remarks. Tryphosella freycinet is one of the group of six Australian species with stout striated robust setae on the outer rami of uropods 1 and 2 (see Remarks under T. fortescue ). Only two species, T. freycinet and T. sorell , have all of the robust setae in this form. Tryphosella freycinet differs from T. sorell in having an obtuse palm on gnathopod 2 (transverse in T. sorell ), urosomite 1 with a wedge-shaped boss, obliquely truncated apically (rounded in T. sorell ) and only one apical robust seta on each lobe of the telson (two in T. sorell ).

Tryphosella freycinet was uncommon (up to 117 specimens per trap) in baited traps set at 12 to 13 m depth off the east coast of Tasmania .

Distribution. Tasmania, southern Australia; 12–50 m depth.

Figures

FIGURE 27. Tryphosella freycinet sp. nov. Holotype, female, 5.0 mm, AM P.69467; paratype, male, 4.5 mm, AM P.69468; Freycinet Peninsula, Tasmania. Scales represent 0.1 mm.

FIGURE 28. Tryphosella freycinet sp. nov. Holotype, female, 5.0 mm, AM P.69467, Freycinet Peninsula, Tasmania. Scales represent 0.2 mm.

FIGURE 29. Tryphosella freycinet sp. nov. Holotype, female, 5.0 mm, AM P.69467; paratype, male, 4.5 mm, AM P.69468; Freycinet Peninsula, Tasmania. Scales represent 0.1 mm.