Aristias nowra, Stoddart & Lowry, 2010

Stoddart, H. E. & Lowry, J. K., 2010, The family Aristiidae (Crustacea: Amphipoda: Lysianassoidea) in Australian waters, Zootaxa 2549 (1), pp. 31-53 : 36-41

Aristias nowra sp. nov.

( Figs 7–9 )

Type material. HOLOTYPE, female, 3.6 mm, MV J17160 , 52 km east of Nowra , New South Wales, Australia, 34°53.57'S 151°14.09'E, 1011 m, green-grey sandy mud, box corer, 23 October 1988, G.C.B. Poore et al., RV Franklin, stn SLOPE 62 . PARATYPE, male, 3.2 mm, MV J59374 , 48 km east-north-east of Cape

Tourville , Tasmania, Australia, 42°00.25'S 148°43.55'E, 1264 m, gravel with lumps of sandy mud aggregate, WHOI epibenthic sled, 30 October 1988, G.C.B. Poore et al., RV Franklin, stn SLOPE 81 .

Type locality. 52 km east of Nowra , New South Wales, Australia, 34°53.57'S 151°14.09'E, 1011 m depth .

Etymology. The species is named for its type locality.

Diagnostic description. Head lateral cephalic lobe rounded; eyes poorly developed, oval. Antenna 1 accessory flagellum 2-articulate. Antenna 2 calceoli not present in male. Epistome and upper lip with central notch. Mandible lacinia mobilis present on left mandible; molar a weakly setose flap. Maxilla 1 inner plate with 5 pappose setae along inner margin; outer plate with 8 setal-teeth in a 6/2 arrangement, most with moderate number of cusps. Maxilliped palp 4-articulate, palp article 1 with lateral margin much longer than medial margin.

Gnathopod 1 parachelate; carpus shorter than propodus, without posterodistal lobe; propodus posterior margin dentate, with 2 robust setae along posterior margin. Gnathopod 2 carpus longer than propodus. Pereopods 5–7 propodus with anterodistal spur. Pereopod 5 coxa posterior lobe deeper than anterior lobe, long, triangular; basis moderately expanded posteriorly, with posteroventral lobe. Pereopod 6 coxa posterior lobe deeper than anterior lobe, long, triangular; basis moderately expanded posteriorly, with posteroventral lobe. Pereopod 7 basis moderately expanded posteriorly, posterior margin abruptly tapered distally, with posteroventral lobe, posteroventral corner rounded.

Epimeron 3 posterior margin smooth, posteroventral corner subquadrate. Urosomite 1 smooth dorsally, without a dorsodistal boss. Urosomite 3 with dorsolateral flanges. Uropod 3 rami with robust setae only on apices of outer ramus article 1; inner ramus longer than article 1 of outer ramus. Telson shorter than broad, deeply cleft, without mid-dorsal robust setae, lateral margins curved, uniformly tapering distally, without robust setae on lateral margins, with 1 apical robust seta on each lobe.

Remarks. Based on maxilla 1 with 8 or 9 cuspidate setal-tooth arrangement, pereopods 5–7 each with a spur on the propodus, pereopod 7 with a cutaway basis and epimeron 3 with a subquadrate or acute posteroventral corner, A. nowra appears to be most similar to A. bicornuta from the Caribbean Sea, A. captiva from the Gulf of Mexico and A. topsenti from Newfoundland. Only A. nowra and A. topsenti have a flange on urosomite 3, but the detailed structure of the flange appears to be different. Aristias nowra can be distinguished from A. topsenti by: the presence of a lacinia mobilis on the mandible, a triangular posterior lobe on coxae 5 and 6 and the shorter than broad telson.

Distribution. South-eastern Australia in 1011–1264 m depth.

Figures

FIGURE 7. Aristias nowra sp. nov. Holotype, female, 3.6 mm, MV J17160.

FIGURE 8. Aristias nowra sp. nov. Holotype, female, 3.6 mm, MV J17160. Scales represent 0.1 mm.

FIGURE 9. Aristias nowra sp. nov. Holotype, female, 3.6 mm, MV J17160. Scales represent 0.1 mm.