Tryphosella chinchilla, 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 : 30-34

Tryphosella chinchilla sp. nov.

( Figs 17–19 )

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

Type material. HOLOTYPE, female, ovigerous (5 eggs), 5.0 mm, AM P.71611, east of Fitzroy Reef , Great Barrier Reef, Queensland, Australia, 23°32'53"S 152°16'44"E, 400 m, baited trap, 3–4 June 1994, J.K. Lowry & K. Dempsey, MV Reefknot, stn QLD-1105 . PARATYPES: 1 male, 4.0 mm, AM P.71612; 1 female, ovigerous, 4.5 mm, AM P.71613; 723 specimens, AM P.52076; same data as Holotype . 240 specimens, AM P.52075, same data, stn QLD-1103 ; 368 specimens, same data, 2–3 June 1994, stn QLD-1085 ; 213 specimens, AM P.52072, same data, stn QLD-1087 .

Additional material examined. Queensland: 1 specimen, AM P.49509, east of Flynn Reef, 16°40.14'S 146°20.03’E, 300 m, baited trap, 6–7 June 1993, J.K. Lowry, P. Freewater & W. Vader, RV Sunbird , stn QLD-924 ; 1 specimen, AM P.49516, same data, stn QLD-926 ; 1 specimen, AM P.50223, east of Flynn Reef, 16°39.92'S 146°20.71’E, 400 m, baited trap, 12.2°C, 6–7 June 1993, J.K. Lowry, P. Freewater & W. Vader, RV Sunbird , stn QLD-927 ; 1 specimen, AM P.50225, same data, stn QLD-928 ; 1 specimen, AM P.50285, same data, 7–8 June 1993, stn QLD-945 ; 6 specimens, AM P.50323, east of Flynn Reef, 16°40.14'S 146°20.03'E, 300 m, baited trap and sediment, 18–19 May 1994, J.K. Lowry & K. Dempsey, RV Sunbird , stn QLD-1040 ; 2 specimens, AM P.50329, same data, stn QLD-1042 ; 2 specimens, AM P.50334, east of Flynn Reef, 16°06.8'S 146°E, 600 m, baited trap, 6.8 °C, 18–19 May 1994, J.K. Lowry & K. Dempsey, RV Sunbird , stn QLD-1047 ; 1 specimen, AM P.49538, same data, stn QLD-1048 ; 1 specimen, AM P.49549, east of Flynn Reef, 16°39.00'S 146°21.79'E, 600 m, baited trap, 19– 20 May 1994, J.K. Lowry & K. Dempsey, RV Sunbird , stn QLD-1068 ; 2 specimens, AM P.52021, east of Fitzroy Reef, 23°32.16'S 152°17.98’E, 203 m, baited trap, 17.8°C, 16–17 June 1993, J.K. Lowry, P. Freewater & R. Springthorpe, MV Reefknot , stn QLD-959 ; 36 specimens, AM P.52022 and 5 specimens, AM P.52646, east of Fitzroy Reef, 23°30.46'S 152°21.32’E, 300 m, baited trap, 15.4°C, 16–17 June 1993, J.K. Lowry, P. Freewater & R. Springthorpe, MV Reefknot , stn QLD-960 ; 37 specimens, AM P.52023, east of Fitzroy Reef, 23°30.46'S 152°21.32’E, 300 m, baited trap, 15.4°C, 16–17 June 1993, J.K. Lowry, P. Freewater & R. Springthorpe, MV Reefknot , stn QLD-961 ; 73 specimens, AM P.49457 and 7 specimens, AM P.52647, east of Fitzroy Reef, 23°26.17'S 152°28.46’E, 400 m, baited trap, 14.2°C, 16–17 June 1993, J.K. Lowry, P. Freewater & R. Springthorpe, MV Reefknot , stn QLD-963 ; 75 specimens, AM P.52024, same data, stn QLD-965 ; 443 specimens, AM P.52025 and 1 male, 4.0 mm, P.71614, east of Fitzroy Reef, 23°32'53"S 152°16'44"E, 300 m, baited trap, J.K. Lowry & K. Dempsey, MV Reefknot , 2–3 June 1994, stn QLD-1082 ; 363 specimens, AM P.52070, same data, stn QLD-1083 ; 67 specimens, AM P.52073, same data, 3–4 June 1994, stn QLD-1100 ; 103 specimens, AM P.52074, same data, stn QLD- 1102 .

Type locality. East of Fitzroy Reef , Great Barrier Reef, Queensland, Australia, 23°32'53"S 152°16'44"E, 400 m depth .

Etymology. Named for the outback town of Chinchilla in central Queensland.

Diagnostic description. Body not expanded to form a lateral bulge, without dorsal carina. Head lateral cephalic lobe semidome, 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 strong 2-field callynophore, robust setae present on 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 slightly 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 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 3 long apical robust setae.

Gnathopod 1 subchelate; coxa medium length (length 1.6 x breadth), subtriangular, tapering distally; basis densely 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 moderately 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 longer than broad, without photophore, 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 deeply cleft, with dorsal robust setae, with 1 apical robust seta on each lobe.

Male (sexually dimorphic characters). Antenna 1 calceoli present, small. Antenna 2 calceoli present.

Remarks. Only three Australasian species of Tryphosella ( T. chinchilla , T. cooee and T. rodondo ) have a densely setose anterior margin on the basis of gnathopod 1. Tryphosella chinchilla and T. cooee both differ from T. rodondo in having robust setae on the proximal articles of the flagellum of antenna 1. Tryphosella chinchilla is easily distinguished from T. cooee by the broadly rounded epistome (acute in T. cooee ) and the 3 long slender apical setae on the maxilliped outer plate (2 in T. cooee ).

It is interesting to note that both T. chinchilla and T. rodondo have a dense covering of small fine setae on the surface and margins of the oostegites (in addition to the long lateral setae characteristic of lysianassoid oostegites). Tryphosella cooee does not have these unusually setose oostegites.

Tryphosella chinchilla was most commonly taken in baited traps set at 300 to 400 m depth off the central Queensland coast (up to 725 specimens in a trap) .

Distribution. Queensland, eastern Australia; 203–600 m depth.

Figures

FIGURE 17. Tryphosella chinchilla sp. nov. Paratype female, 4.5 mm, AM P.71613, east of Fitzroy Reef, Queensland.

FIGURE 18. Tryphosella chinchilla sp. nov. Holotype, female, 5.0 mm, AM P.71611; paratype, male, 4.0 mm, AM P.71612; east of Fitzroy Reef, Queensland. Scales for G1, G2 represent 0.5 mm, remainder represent 0.2 mm.

FIGURE 19. Tryphosella chinchilla sp. nov. Holotype, female, 5.0 mm, AM P.71611; paratype, male, 4.0 mm, AM P.71612; east of Fitzroy Reef, Queensland. Scales for G1, G2 represent 0.5 mm, remainder represent 0.1 mm.