Tryphosella tathra, 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 : 59-63

Tryphosella tathra sp. nov.

( Figs 41–43 )

Tryphosella sp. 485. — Lowry & Smith, 2003: 56.

Type material. HOLOTYPE, female, ovigerous (4 eggs), 3.8 mm, AM P.70546, off mouth of Moona Moona Creek , Jervis Bay, New South Wales, Australia, 35°03.5'S 150°41'E, 8 m, air-lifted sediment, 17 December 1982, P.B. Berents, stn NSW-263 . PARATYPES: 1 male, 3.2 mm, AM P.70547, same data ; 1 male, 3.1 mm, AM P.70548, same data ; 2 females and 1 male, AM P.70549, same data ; 1 immature specimen, AM P.70545, same data , stn NSW-262; 1 adult male, AM P.70542, same locality , plankton net by hand along bottom, 2100 hrs, 1 December 1983, P.B. & P.M. Berents, stn NSW-1036.

Additional material examined. New South Wales: 1 specimen, AM P.57647, north-east of Coffs Harbour , 30°15.94'S 153°21.90'E, 92.7 m, baited trap, 11–12 August 1993, P. Berents, R. T . Springthorpe & W. Vader, MV Cheryl Lee , stn NSW-870 ; 36 specimens, AM P.52161, same locality, 100 m, baited trap, 18.6°C, 8–9 September 1994, J.K. Lowry & K. Dempsey, MV Carrie Anne , stn NSW-984; 1 ovigerous female (3 eggs), 4.5 mm, AM P.82864, 1 mature male, 4.4 mm, AM P.82865, 1 immature male, 4.0 mm, AM P.82866 and 63 specimens, AM P.52162, same data, stn NSW-985 ; 24 specimens, AM P.52230, same data, 9–10 September 1994, stn NSW-1006 ; 5 specimens, AM P.52231, same data, stn NSW-1007 ; 2 specimens, AM P.48134, due east of Coffs Harbour , 30°17.49'S 153°13.90'E, 50 m, baited trap, 9–10 September 1994, J.K. Lowry & K. Dempsey, MV Carrie Anne , stn NSW-1002; many specimens, AM P.70536, eastern end of Shoal Bay, Port Stephens , 32°42.9'S 152°10.8'E, 6 m, baited trap set in Halophila bed, 30–31 May 1988, J.K. Lowry & S.J. Keable, RV Flying Scud , stn NSW-290 ; 2 specimens, AM P.70538, same data, stn NSW-296 ; 6 specimens, AM P.70537, off Shoal Bay Jetty, Port Stephens , 32°43.1'S 152°10.5'E, 10 m, baited trap set on sand with shelly patches, set 1630 -1730 hrs, retrieved 2030-2230 hrs, 30–31 May 1988, J.K. Lowry & S.J. Keable, RV Flying Scud , stn NSW-292 ; 1 specimen, AM P.70539, same locality, baited trap set in a patch of Zostera , set 0830-1000 hrs, retrieved 1630-1700 hrs, 31 May 1988, J.K. Lowry & S.J. Keable, RV Flying Scud , stn NSW-297 ; 27 specimens, AM P.70540, Barnes Rocks, Port Stephens , 32°41.1'S 152°9.5'E, 5 m, baited trap set among Ecklonia and rocks, set 1000 -1100 hrs, retrieved 0730-0830 hrs, 1–2 June 1988, J.K. Lowry & S.J. Keable, RV Flying Scud , stn NSW-310; 1 ovigerous female , 5 immatures, AM P.70541, Fairlight, Port Jackson , 33°48’S 151°16.5’E, 3 m, baited trap on coarse sand bottom below Ecklonia , 8–9 January 1988, S.J. Keable & D. Townsend, stn 7 ; 7 specimens, AM P.70544, Watsons Bay ferry jetty, Port Jackson , 33°50’48”S 151°16’48”E, 3 m, baited trap on silt/sand near algae, 28–29 August 1993, A. R . Parker ; 7 specimens, AM P.48394, off Wollongong , 34°26.42'S 150°58.04'E, 50 m, baited trap, 19.5°C, 7–8 May 1993, P. Freewater, S. Keable & W. Vader, MV Robin E, stn NSW-792; 8 specimens, AM P.48228, same data, stn NSW-793 ; 8 specimens, AM P.48108, off Wollongong , 34°26.44'S 150°57.55'E, 50 m, baited trap, 19.5°C, 6–7 May 1993, P. Freewater, S. Keable & W. Vader, MV Robin E, stn NSW-773; 4 specimens, AM P.44323, off Wollongong , 34°26.54'S 150°57.98'E, 50 m, baited trap, 28–29 March 1994, J.K. Lowry & K. Dempsey, MV Robin E, stn NSW-956; 15 specimens, AM P.46873, off Wollongong , 34°28.15'S 151°02.37'E, 100 m, baited trap, 15.5°C, 6–7 May 1993, P. Freewater, S. Keable & W. Vader, MV Robin E, stn NSW-776; 3 specimens, AM P.46882, same data, stn NSW-778 ; 20 specimens, AM P.52233, off Wollongong , 34°28.21'S 151°02.29'E, 100 m, baited trap, 15.5°C, 7–8 May 1993, P. Freewater, S. Keable & W. Vader, MV Robin E, stn NSW-795; 1 specimen, AM P.44267, off Wollongong , 34°31.48'S 151°13.22'E, 200 m, baited trap, 12.6°C, 27–28 March 1994, J.K. Lowry & K. Dempsey, MV Robin E, stn NSW-944; 1 specimen, AM P.52232, off Wollongong , 34°32.02'S 151°13.00'E, 200 m, baited trap, 13.7° C, P. Freewater, S. Keable & W. Vader, MV Robin E, 6–7 May 1993, stn NSW-781 ; 24 specimens, AM P.44285, off Wollongong , 100 m, baited trap, 28– 29 March 1994, J.K. Lowry & K. Dempsey, MV Robin E, stn NSW-961.

Type locality. Off mouth of Moona Moona Creek, Jervis Bay, New South Wales, Australia, 35°03.5'S 150°41'E ,

8 m depth. Etymology. The species is named for the town of Tathra on the south coast of New South Wales. Diagnostic description. Head lateral cephalic lobe rounded, 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 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 separate; epistome produced equally with upper lip, narrowly rounded; upper lip slightly produced, rounded apically. 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 and serrations. Maxilliped basis without recurved hook; outer plate with 2 short apical robust setae.

Gnathopod 1 subchelate; coxa small (length 1.0 x breadth), subtriangular, tapering distally; basis sparsely 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 slightly 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, without photophore, 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. Uropods 1 and 2 outer 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 flagellum with strong 2-field callynophore. Antenna 2 flagellum long, calceoli present. Epistome/Upper lip epistome slightly produced beyond upper lip, broadly rounded. Uropod 3 with plumose setae on both rami.

Remarks. Tryphosella tathra 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 tathra is most similar to T. orana in having: a significantly reduced coxa 1; 2 apical robust setae on the outer plate of the maxilliped; a slightly obtuse gnathopod 2 palm; 2 short apicomedial robust setae on the peduncle of uropod 3; and 1 distal robust seta on each lobe of the telson. Tryphosella tathra shows subtle differences from T. orana in the following characters: the epistome is produced equally with the upper lip and narrowly rounded (produced beyond the upper lip and broadly rounded in T. orana ); gnathopod 1 carpus is longer than propodus (subequal in length in T. orana ); and the posteroventral corner of epimeron 3 is subquadrate (narrowly rounded in T. orana ). Tryphosella orana is known only from the south-west corner of Western Australia and T. tathra is known only from the central New South Wales coast in eastern Australia.

Tryphosella tathra occurred frequently along the New South Wales coast from Coffs Harbour to Jervis Bay , most commonly around 100 m depth (up to 66 specimens in a trap) .

Distribution. Central New South Wales coast, eastern Australia; 3–200 m depth.

Figures

FIGURE 41. Tryphosella tathra sp. nov. Holotype, female, 3.8 mm, AM P.70546; paratype, male, 3.2 mm, AM P.70547, Jervis Bay, New South Wales. Scales represent 0.1 mm.

FIGURE 42. Tryphosella tathra sp. nov. Holotype, female, 3.8 mm, AM P.70546, Jervis Bay, New South Wales. Scales represent 0.2 mm.

FIGURE 43. Tryphosella tathra sp. nov. Holotype, female, 3.8 mm, AM P.70546; paratype, male, 3.2 mm, AM P.70547, Jervis Bay, New South Wales. Scales represent 0.1 mm.