Aristias gomoni, 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 : 35-36

Aristias gomoni sp. nov.

( Figs 4–6 )

Type material. HOLOTYPE, female, 7.5 mm, MV J59372 , south of Point Hicks , Victoria, Australia, 38°17.70'S 149°11.30'E, 400 m, coarse sand, gravel, mud, many sponges, WHOI epibenthic sled, 24 July 1986, M.F. Gomon et al., RV Franklin, stn SLOPE 40 . PARATYPES: 5 females, MV J59373 , and 1 female, 6.5 mm, AM P.81145, same data as holotype ; 2 specimens, female, 5.5 mm and immature, 3.5 mm, AM P68502, Ling Hole , off west coast of Tasmania, Australia, 41°23’29”S 144°21’24”E to 41°24’18”S 144°19’15”E, 330 m, Sherman sled, associated with anemones, 20 April 2004, CSIRO party, RV Southern Surveyor, stn SS 04/04/51 .

Type locality. South of Point Hicks , Victoria, Australia, 38°17.70'S 149°11.30'E, 400 m depth .

Etymology. The species is named for Martin Gomon who collected the type specimen.

Diagnostic description. Head lateral cephalic lobe broadly triangular, apically subacute; eyes well developed, reniform. Antenna 1 accessory flagellum 4-articulate. Epistome and upper lip with central notch. Mandible lacinia mobilis present on left mandible; molar a weakly setose flap. Maxilla 1 inner plate with 8 pappose setae along inner margin; outer plate with 14 setal-teeth in a 12/2 arrangement, most with many cusps. Maxilliped palp 4-articulate, palp article 1 with lateral margin much longer than medial margin.

Gnathopod 1 parachelate; carpus subequal in length to propodus, without posterodistal lobe; propodus posterior margin dentate, with 5 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, short, triangular; basis moderately expanded posteriorly, with posteroventral lobe. Pereopod 6 coxa posterior lobe deeper than anterior lobe, short, triangular; basis greatly expanded posteriorly, with posteroventral lobe. Pereopod 7 basis greatly expanded posteriorly, posterior margin abruptly tapered distally, with posteroventral lobe, posteroventral corner rounded.

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

Remarks. Based on pereopods 5–7 propodus each with a spur, pereopod 7 basis with a tapering posterior margin and epimeron 3 with a narrowly rounded posteroventral corner, A. gomoni is similar to A. stenopodus from just north of Madagascar and to A. verdensis from the Philippine Islands. Aristias gomoni is distinguished from these species by the large number of setal-teeth (14) on the outer plate of maxilla 1.

Distribution. South-eastern Australia in 330–429 m depth.

Figures

FIGURE 4. Aristias gomoni sp. nov. Paratype, female, 6.5 mm, AM P.81145.

FIGURE 5. Aristias gomoni sp. nov. Holotype, female, 7.5 mm, MV J59372. Scales represent 0.1 mm.

FIGURE 6. Aristias gomoni sp. nov. Holotype, female, 7.5 mm, MV J59372. Scales represent 0.1 mm.