Tirons of the world: a review of ‘ tironid’ amphipods, description of new genera and species, and establishment of a new subfamily Tironinae Stebbing, 1906 stat. nov. (Crustacea, Synopiidae) Author Just, Jean text Zootaxa 2022 2022-05-23 5139 1 1 89 http://zoobank.org/145cb6f5-2ea8-40b0-9cca-3e942aa4a5b9 journal article 95147 10.11646/zootaxa.5139.1.1 8ab25605-ec09-4d57-9dbd-7da2b032e5e8 1175-5326 6572023 145CB6F5-2EA8-40B0-9CCA-3E942AA4A5B9 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. FIGURE 8. Tironella bathyalis gen. et sp. nov. Holotype, ♀, except P , Pseudotiron pervicax . clv , head lateral view; mx1 , maxilla 1; P clv , lateral view of head of P. pervicax (from J.L. Barnard, 1967 , fig. 84 k); tel , telson; us , urosome. FIGURE 9. Tironella bathyalis gen. et sp. nov. Holotype, ♀, except P , Pseudotiron pervicax . dac , dactylus with unguis; P dac , dactylus with unguis of P. pervicax (from J.L. Barnard, 1967 , fig. 84 g); gp1 , gnathopod 1; p4–7 , pereopods 4 to 7. 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 .