Parschisturella martrudan sp. nov.

(Figs 30–32)

Types. Holotype, female, 12.0 mm, AM P.69042, east of Broken Bay, New South Wales, Australia (33°37'S 152°04'E to 33°39’S 152°02’E), 896–923 m, dredge, 10 December 1980, R. T. Springthorpe, FRV Kapala [K80-20- 09] . Paratypes: 1 male, 10.2 mm, AM P.69044, north-east of Port Jackson, New South Wales, Australia (33°41’S 152°00’E to 33°44’S 151°57’E), 820–888 m, beam trawl, 11 February 1986, R. T. Springthorpe, FRV Kapala [K86-01-07] ; 1 female, 12.8 mm, AM P.69045, east of Broken Bay, New South Wales, Australia (33°30’S 152°09’E to 33°33’S 152°11’E), 922–1015 m, beam trawl, 12 February 1986, R. T. Springthorpe, FRV Kapala [K86-01-08] .

Type locality. East of Broken Bay, New South Wales, Australia (33°37'S 152°04'E to 33°39’S 152°02’E), 896–923 m depth.

Additional material described. New South Wales. 1 specimen, AM P.44445, off Wollongong (34°32.25'S 151°15.16'E), 300 m, baited trap, 6 May 1993 – 7 May 1993, P. Freewater & party, MV Robin E [NSW-782] ; 3 specimens, AM P.69041, east of Broken Bay (33°31’S 152°08’E to 33°33’S 152°07’E), 914 m, 2.5 m sled dredge, 10 December 1980, R. T. Springthorpe, FRV Kapala [K80-20-08] ; 2 females, AM P.69043, east of Broken Bay (33°37’S 152°04’E to 33°39’S 152°02’E), 896–923 m, dredge, 10 December 1980, R. T. Springthorpe, FRV Kapala [K80-20-09] ; 1 male, AM P.69046, east of Broken Bay (33°30’S 152°09’E to 33°33’S 152°11’E), 922–1015 m, beam trawl, 12 February 1986, R. T. Springthorpe, FRV Kapala [K86-01-08] ; 1 specimen, AM P.69047, east of Broken Bay (33°30’S 152°12’E to 33°33’S 152°09’E), 1053–1066 m, beam trawl, 12 February 1986, R. T. Springthorpe, FRV Kapala [K86-01-10] .

Tasmania. 16 specimens, AM P.51146; 8 specimens, AM P.51164, east of Fortescue Bay (43°08.97’S 148°15.37’E), 1000 m, baited trap, 16–17 April 1993, J.K. Lowry & P. Freewater, MV Tasmanian Enterprise [TAS-365 & TAS-367]; 539 specimens, AM P.51176; 503 specimens, AM P.51179, east of Fortescue Bay (43°08.97’S 148°15.37’E), 1000 m, baited trap, 17–18 April 1993, J.K. Lowry & P. Freewater, MV Tasmanian Enterprise [TAS-383 & TAS-384]; 5 specimens, AM P.51310; 10 specimens, AM P.51313; 41 specimens, AM P.51381; 180 specimens, AM P.57977, east of Fortescue Bay (43°08.97’S 148°15.37’E), 1000 m, baited trap, 8–9 April 1994, J.K. Lowry & K. Dempsey, MV Martrudan [TAS-401, TAS-403 & TAS-422-423]; 43 specimens, AM P.51357, east of Fortescue Bay (43°08.97’S 148°15.37’E), 1000 m, baited trap, 9–10 April 1994, J.K. Lowry & K. Dempsey, MV Martrudan [TAS-419]; 315 specimens, AM P.51388; 1 specimen, AM P.56090, east of Fortescue Bay (43°08.97’S 148°15.37’E), 1000 m, baited trap, 9–10 April 1994, J.K. Lowry & K. Dempsey, MV Martrudan [TAS-421]; many specimens, AM P.73705, 76.8km south-south-east of South East Cape, Main Pedra Hill (44°15.6'S 147°07.8'E), 1312 m, baited trap, 21–24 January 1997, CSIRO party, FRV Southern Surveyor [SS01/97/ 08]. 4 specimens, NMV J67753, 48 km east-north-east of Cape Tourville (42°00.25'S 148°43.55'E to 41°57.77'S 148°42.08'E), 1264– 1130 m, gravel with lumps of sandy mud aggregate, WHOI epibenthic sled, 30 October 1988, G.C.B. Poore et al., RV Franklin [SLOPE 81]; 19 specimens, NMV J67754, off Freycinet Peninsula (42°2.20 'S 148°38.70'E), 800 m, coarse shelly sand, WHOI epibenthic sled, 27 July 1986, M.F. Gomon et al., RV Franklin [SLOPE 45] .

Victoria. 2 specimens, NMV J67755, south of Point Hicks (38°19.60'S 149°24.30'E), 930 m, rock, rubble, clay, sand, biogenic sediment, WHOI epibenthic sled, 23 July 1986, M.F. Gomon et al., RV Franklin [SLOPE 33] .

Etymology. Named for the beautiful crayfishing boat MV Martrudan which collected many of the amphipods used in this and other studies of Australian lysianassoid amphipods; used as a noun in apposition.

Description. Based on holotype, female, 12.0 mm, AM P.69042. Head, lateral cephalic lobes subtriangular, apically subacute. Antenna 1 peduncular article 1 without anterodistal lobe; accessory flagellum not forming cap, 5-articulate, terminal article not offset; primary flagellum with strong 1-field callynophore; robust setae absent from proximal articles; calceoli absent. Antenna 2 peduncular article 3 short, articles 3 to 5 not enlarged, brush setae absent; flagellum short; calceoli absent. Labrum, epistome and upper lip separate; epistome less produced than upper lip, straight; upper lip produced, strongly acute apically. Mandible incisor large, left and right symmetrical; molar with asymmetrically reduced column, proximally setose, distally triturating; palp attached about midway, article 2 margins subparallel, article 3 blade-like. Maxilla 1 outer plate setal-tooth 7 present, left and right symmetrical, cuspidate distally along inner margin; palp distal margin with apical robust setae. Maxilliped outer plate with one slender and one broad apical robust setae.

Gnathopod 1 simple; coxa large, about as long as coxa 2, subrectangular with straight anterior margin; basis moderately to densely setose along anterior margin; ischium long (length 2 × to 4 × breadth); carpus long (length 2 to 4 × breadth), slightly longer than propodus, without posterior lobe; propodus margins tapering distally; dactylus simple. Gnathopod 2 propodus palm transverse, dactylus distinctly shorter than palm. Pereopod 4 coxa with a well-developed posteroventral lobe. Pereopod 5 coxa without distinct lateral ridge; basis about as long as broad, posterior margin weakly or not serrate. Pereopod 7 basis posterodistally produced less than halfway along merus.

Pleonite 3 without mid-dorsal carina, not produced dorsodistally, posterodorsal margin not produced. Epimeron 3 posterior margin smooth, posteroventral corner acutely produced, forming weak spine. Urosomite 1 not projecting over urosomite 2, dorsally rounded. Uropod 2 inner ramus with slight constriction. Uropod 3 peduncle without dorsolateral flange; outer ramus article 2 short, with few plumose setae on inner ramus. Telson moderately cleft, without dorsal robust setae, with 2 apical robust setae on each lobe.

Sexually dimorphic characters. Based on paratype male, 10.2 mm, AM P.69044. Antenna 1 primary flagellum with strong 2-field callynophore; robust setae absent from proximal articles; calceoli present. Antenna peduncular brush setae present; calceoli present. Uropod 3 peduncle without dorsolateral flange; outer ramus article 2 short, with plumose setae on both rami.

Depth range. 820–1312 m.

Remarks. Parschisturella martrudan and P. simplex appear to be the only species with truly simple first gnathopods. In Parschisturella martrudan the cusps on the medial margin of setal-tooth 7 are distal in P. martrudan (along most of the medial margin in P. simplex); the gnathopod 2 dactylus is shorter than the palm in P. martrudan (fitting the palm in P. simplex); the dorsal margin of urosomite 1 is evenly rounded in P. martrudan (straight in P. simplex) and the telson is moderately cleft (deeply cleft in P. simplex).

Distribution. Australia. New South Wales: east of Broken Bay; off Wollongong. Tasmania: east of Fortescue Bay; south-south-east of South East Cape, Main Pedra Hill; east-north-east of Cape Tourville. Victoria: south of Point Hicks.