Tryphosella tuckanarra, 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 : 66-70

Tryphosella tuckanarra sp. nov.

( Figs 47–49 )

Type material. HOLOTYPE, female, ovigerous, 3.1 mm, AM P.70523, Vancouver Peninsula , near Mistaken Island, King George Sound, Western Australia, Australia, 35°04'S 117°56'E, 2 m, grey sponge with crinoids, 13 December 1983, R. T. Springthorpe, stn WA-114 . PARATYPES: 1 immature, AM P.70524, same data as Holotype ; 1 juvenile, AM P.70498, Vancouver Peninsula , near Mistaken Island, King George Sound, Western Australia, Australia, 35°04'S 117°56'E, 2 m, sponges, 13 December 1983, J.K. Lowry, stn WA-101 ; 1 male, 3.1 mm, AM P.70499, same data , stn WA-103; 4 specimens, AM P.70500, same locality , 2 m, soft corals and Caulerpa , 13 December 1983, J.K. Lowry, stn WA-106; 1 specimen, AM P.70525, same locality , 2 m, sponge covered with short green alga (? Caulerpa ), 13 December 1983, R. T. Springthorpe, stn WA-119; 1 ovigerous female, 3.4 mm, AM P.70526 and 1 ovigerous female, AM P.70527, same locality , 6 m, sea grass, 13 December 1983, R. T. Springthorpe, stn WA-121 .

Additional material examined. Western Australia: 1 ovigerous female and 1 immature, AM P.70528, off Possession Point, King George Sound , 35°02.5'S 117°55'E, 7 m, mixed brown algae, bryozoans, sponge , R. T. Springthorpe & J.K. Lowry, 14 December 1983 , stn WA-133; 2 juveniles, AM P.70529, rocks near Migo Island, Port Harding, Torbay Bay , 35°04'S 117°39'E, 6–7 m, small branched alga with compound tunicate on underside of branches, 15 December 1983 , R. T. Springthorpe & J.K. Lowry, stn WA-152 .

Type locality. Vancouver Peninsular , near Mistaken Island, King George Sound, Western Australia, Australia, 35°04'S 117°56'E, 2 m depth .

Etymology. Named for the tiny village of Tuckanarra located about about 580 km north-northeast from Perth.

Diagnostic description. Head lateral cephalic lobe subtriangular, apically subacute; eyes apparently absent. Antenna 1 peduncular articles 1 and 2 without anterodistal lobe; accessory flagellum not forming cap, terminal article not offset; flagellum with weak 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 epistome slightly 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 outer plate with 2 short apical robust setae.

Gnathopod 1 subchelate; coxa medium length (length 1.5 x breadth), subtriangular, tapering distally; basis moderately 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 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 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 subquadrate. Urosomite 1 not projecting over urosomite 2, with rounded boss. Uropods 1 and 2 rami with distal stout striated robust setae. Uropod 2 inner ramus without constriction. Uropod 3 peduncle without dorsolateral flange, with 2 short apicomedial robust setae; 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). Antenna 1 calceoli present. Antenna 2 flagellum long, calceoli present. Unfortunately a fully-developed male is not present in the collections.

Remarks. Tryphosella tuckanarra 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 ). Tryphosella tuckanarra is very similar to T. fortescue in having a transverse palm on gnathopod 2, 2 short apicomedial robust setae on the peduncle of uropod 3 and 2 apical robust setae on each lobe of the telson. Tryphosella tuckanarra is distinguished from T. fortescue by the rounded lateral cephalic lobe (subtriangular in T. fortescue ), the less reduced coxa 1 and the presence of 2 apical robust setae on the outer plate of the maxilliped (3 in T. fortescue ).

Tryphosella tuckanarra is known only from King George Sound and Torbay Bay in shallow-water. It has never been taken in traps.

Distribution. South-western Western Australia, 2–7 m depth.

Figures

FIGURE 47. Tryphosella tuckanarra sp. nov. Paratype, female, 3.4 mm, AM P.70526, King George Sound, Western Australia.

FIGURE 48. Tryphosella tuckanarra sp. nov. Holotype, female, 3.1 mm, AM P.70523; paratype male, 3.1 mm, AM P.70499; King George Sound, Western Australia. Scales represent 0.1 mm.

FIGURE 49. Tryphosella tuckanarra sp. nov. Holotype, female, 3.1 mm, AM P.70523, King George Sound, Western Australia. Scales represent 0.1 mm.