Tironella bathyalis sp. nov.

(Figs 8–9)

Type fixation. Holotype, ♀.—Here designated.

Etymology. The epithet reflects that this species occur at upper bathyal depth on the eastern Bass Strait slope.

Material examined. Holotype, ♀, 5.4 mm. Australia, New South Wales, Off Eden, 37˚00.36’S, 150˚20.42’E, 363 m, coarse shell, epibenthic sled, GCB Poore et al., 16 February 1987, RV Franklin, SLOPE stn 22, NMV J73738.

Paratypes. Same data as holotype, NMV J75150 (anterior half of adult ♀, 1 young specimen of 4.4 mm) .

Description (female). Rostrum apex sharply right-angled. Interantennal lobes bluntly rounded at nearly right angle.

Mouthparts. Maxilla 1 palp apex with 5 acute, finely deticulate setae and 1 lateral curved seta; outer plate with 9 variously dentate spine-setae. Mouthparts otherwise normal.

Antenna 1 as long as pereonite 1–6 combined along dorsum, peduncle article 2 about 2/3 length of 1, article 3 as long as article 2, articles 1 and 2 with robust seta in dorsoapical corner, otherwise sparsely setose; flagellum about 1.2 longer than peduncle, of 10 articles, accessory flagellum of 4 articles. Antenna 2 as long as pereonites 1–7 combined along dorsum, peduncular article 4 the longest, flagellum of 8+ articles, most articles with single slender robust seta dorsodistally, antenna otherwise sparsely setose.

Gnathopods 1 and 2 basis with row of long setae anteriorly and a few long setae on posterior margin; propodus of pereopod 1 with row of strong pectinate setae, of gnathopod 2 with simple setae.

Pereopods 3–4 basis about 5 times longer than wide, as long as rest of pereopod, with anterior margin row of small setae, a few longer setae in posterodistal corner. Pereopod 5 basis broadest in distal half. Pereopod 6 basis ovoid. Pereopod 7 basis nearly circular, shorter than pereopod 6 basis, medial surface with row of small setae and similar scattered setae, propodus about half as long as carpus.

Uropod 2 rami presumed of subequal length (see Fig.10 us) reaching to base of outer ramus of uropod 3. Uropod 3 peduncle about half as long as outer ramus, rami elongate oval, reaching beyond apex of telson, outer ramus with row of 8 robust setae dorsally, and 8–9 smaller robust setae ventrally, inner ramus reaching to 9/10 of outer ramus, dorsal margin with row of long setae and 2 robust setae, pointed apex with 2 robust setae.

Telson. Length about 4 times greatest lateral depth, reaching 3/4 along outer ramus of uropod 3, length/width 2.5, with row of 7 small robust setae and a few small simple setae dorsally on each lobe, apices with 1 long and 1 short robust seta.

Size. Largest ♀, 5.4 mm. ♂ not known.

Distribution. SE Australian slope; 363 m.