Aristias poorei, 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 : 43-44

Aristias poorei sp. nov.

( Figs 13–15 )

Type material. HOLOTYPE, female, 4.4 mm, MV J59377 , south of Point Hicks , Victoria, Australia, 38°21.90'S 149°20.00'E, 1000 m, WHOI epibenthic sled, 23 July 1986, G.C.B. Poore et al., RV Franklin, stn SLOPE 32 . PARATYPES: male, 3.8 mm, MV J59378 and 1 female, 4.2 mm, MV J59379 and 3 specimens, AM P.71819, same data as holotype; 2 specimens, MV J39380 , south of Point Hicks , Victoria, Australia, 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 , stn SLOPE 33 .

Type locality. South of Point Hicks , Victoria, Australia, 38°21.90'S 149°20.00'E, 1000 m depth .

Etymology. The species is named for Gary Poore who collected the type specimen and has made much lysianassoid material available for our studies.

Diagnostic description. Head lateral cephalic lobe rounded; eyes well 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 7 setal-teeth in a 5/2 arrangement, most with moderate number of cusps. Maxilliped palp 4-articulate, palp article 1 with lateral and medial margins about same length.

Gnathopod 1 subchelate; carpus shorter than propodus, without posterodistal lobe; propodus posterior margin dentate, with 4 robust setae (in pairs) along posterior margin. Gnathopod 2 carpus longer than propodus. Pereopods 5–7 propodus without anterodistal spur. Pereopod 5 coxa posterior lobe deeper than anterior lobe, short, distally rounded; basis moderately expanded posteriorly, with posteroventral lobe. Pereopod 6 coxa posterior lobe deeper than anterior lobe, long, distally truncated; basis greatly expanded posteriorly, with posteroventral lobe. Pereopod 7 basis greatly expanded posteriorly, posterior margin evenly curved, with posteroventral lobe, posteroventral corner rounded.

Epimeron 3 posterior margin smooth, posteroventral corner subacute. Urosomite 1 with an anterodorsal depression and a rounded dorsodistal boss. Urosomite 3 without dorsolateral flanges. Uropod 3 rami without robust setae; inner ramus longer than article 1 of outer ramus. Telson longer than broad, moderately cleft, without mid-dorsal robust setae, lateral margins curved, abruptly tapering distally, without robust setae on lateral margins, without apical robust setae.

Remarks. Aristias poorei has the same maxilla 1 setal-tooth arrangement as A. thio from New Caledonia. They are also among the few species of Aristias without a distal spur on the propodus of pereopods 5–7. They differ from each other in the posteroventral corner of epimeron 3 which is slightly produced and subacute in A. poorei and narrowly rounded in A. thio . Based on these characters A. poorei and A. thio are considered as sister-species.

Distribution. South-eastern Australia in 930–1000 m depth

Figures

FIGURE 13. Aristias poorei sp. nov. Paratype, female, 4.2 mm, MV J59377.

FIGURE 14. Aristias poorei sp. nov. Holotype, female, 4.4 mm, MV J59377. Scales represent 0.1 mm.

FIGURE 15. Aristias poorei sp. nov. Holotype, female, 4.4 mm, MV J59377. Scales represent 0.2 mm.