Glandulotiron bassianus, Just, 2022

Just, Jean, 2022, 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), Zootaxa 5139 (1), pp. 1-89 : 48-49

Glandulotiron bassianus sp. nov.

( Figs 27–28 )

Type fixation. Holotype, ♀.—Here designated.

Etymology. The species dominates on the easternmost Bass Strait lower shelf and upper slope towards the Tasman Sea.

Material examined. Holotype, ♀, 7.0, mm. Australia, New South Wales, off Eden , 37˚0.60’S, 150˚20.70’E, 363 m, coarse shell, WHOI epibenthic sled, G.C.B. Poore et al., 21 July 1986, RV Franklin, SLOPE stn 22, NMV J73742 .

Paratypes (approximately 100 specimens). Same data as holotype, NMV J75158 (ca. 40) . Same data as holotype, NMV J75159 (> 50 specimens) . Australia, New South Wales, off Nowra , 34˚59.52’S, 151˚5.94’E, 204 m, G.C.B Poore et al., 14 July 1986, RV Franklin, SLOPE stn 1, NMV J73731 (ca. 20 ♀♀) . Australia, Bass Strait, south of point Hicks , 38˚21.90’S, 149˚20.00’E, 1000 m, G.B.C. Poore et al., 23 July 1986, RV Franklin, SLOPE stn 32, NMV J75157 (1 small specimen) . Australia, Tasmania, Western Bass Strait , 70 km SW of Cape Otway, 39˚26’18’’S, 143˚06’48’’E, 115 m, medium sand, S-M grab, RV Tangaroa , stn BSS194 , NMV J73736 (1 ♂) . Australia, Bass Strait, off Point Hicks , 38˚40.80’S, 149˚9.30’E, 200 m, coarse sand, gravel, M.F. Gomon et al., 24 July 1986, RV Franklin, SLOPE stn 41, NMV J73739 (1 specimen) . Australia, Tasmania, off Freycinet Peninsula , 41˚57.50’S, 148˚37.90’E, 400 m, coarse shell, WHOI epibenthic sled, M.F. Gomon et al., 27 July 1986, RV Franklin, SLOPE stn 48, NMV J73740 (> 40, mostly ♀♀ and juveniles) . Australia, Tasmania, off Freycinet Peninsula , 41˚57.50’S, 148˚37.90’E, 400 m, coarse shell, WHOI epibenthic sled, M.F. Gomon et al., 27 July 1986, RV Franklin, SLOPE stn 48, NMV J75160 (3 ♂♂) . Australia, Bass Strait, south of Point Hicks , 38˚17.70’S, 149˚11.30’E, 400 m, WHOI epibentic sled, coarse sand, gravel, mud, sponges, M.F. Gomon et al., 24 July 1986, RV Franklin, SLOPE stn 40, NMV J73741 (many) . Australia, Tasmania, off Freycinet Peninsula , 41˚58.60’S, 148˚38.80’E, 500–600 m, coarse shell, WHOI epibentic sled, M.F. Gomon et al., 27 July 1986, RV Franklin, SLOPE stn 47, NMV J73743 (1 damaged ♀) . Australia, New South Wales, off Eden , 37˚07.30’S, 150˚21.80’E, 520 m, grey coarse shell, WHOI epibenthic sled, GCB Poore et al., 20 July 1986, RV Franklin, SLOPE stn 19, NMV J73744 (2 specimens) . Australia, New South Wales, off Eden , 37˚0.60’S, 150˚20.70’E, 363 m, coarse shell, WHOI epibenthic sled, G.C.B. Poore et al., 21 July 1986, RV Franklin, SLOPE stn 22, NHMD 916115 (5 specimens) .

Description (female). Head dorsal surface smooth. Rostrum broad rounded apically. Interantennal lobe evenly truncate with broadly rounded subequal corners. Accessory eyes composed of 4 ommatidia;

Mouthparts. Maxilla 1 palp apex with 1 pointed lateral seta and 6 short multi-dentate setal spines. Mouthparts otherwise normal.

Antenna 1 as long as pereonite 1–5.5 combined along dorsum, peduncle article 2 about 2/3 length of 1, article 3 about 2/3 length of article 2, article 1 with single penicillate seta ventrally in posterior half and two middorsally; flagellum slightly longer than peduncle, of 8+ articles, accessory flagellum of 3 articles. Antenna 2 as long as pereonites 1–6.5 combined along dorsum, peduncular article 4 the longest; flagellum of 6+ articles, several articles with single slender robust seta dorsodistally, antenna otherwise sparsely setose.

Coxal plates 1–4 distally fringed with setae of varying length, with brim of fine setules. Plate 3 elongate, distal margin broadly rounded.

Gnathopod 1 and 2 of subequal length (left gnathopod 1 shorter, probably regenerated); basis of gnathopod 1 with a few long and some short setae posteriorly and many unequal setae on anterior margin, propodus with a row of 5 stout pectinate setae, dactylus with unguis 3/5 length of propodus, nearly straight. Gnathopod 2 basis with many unequally long setae on posterior and anterior margins, carpus with several groups of unequally long setae on anterior margin, posterior margin with 10–12 groups of long and shorter setae, propodus with simple anterior and posterior setae.

Pereopods 3–4 basis with few marginal setae and single robust seta anterodistally.

Pereopods 5-7 basis broadly rounded posterodistally. Pereopod 5 basis broadest in distal half. Pereopod 6 basis narrow ovoid. Pereopod 7 broadest with nearly parallel margins, medial surface with several long setae, posteroproximal lobe slightly angular, merus with 4 robust setae on posterior margin, several robust setae among many simple setae on anterior margin, carpus with 4 groups of robust setae on anterior margin, propodus about half as long as carpus.

Uropod 1 peduncle reaching to end of peduncle of uropod 2, rami of equal length, about 2/3 length of peduncle, overreaching rami of uropod 2 with about half their length, reaching about 2/3 along outer ramus of uropod 3. Uropod 2 outer ramus shorter than inner ramus. Uropod 3 peduncle about 3/4 length of outer ramus, rami elongate, reaching beyond apex of telson, outer ramus basal article with row of 7 robust setae dorsally, and 3 tiny robust setae ventrally, small second article with 3 dorsal robust setae; inner ramus reaching to 9/10 of basal article of outer ramus, dorsal margin with row of long setae and 2 robust setae, apex with 3 robust setae.

Telson. Length about 3.5 times greatest depth in lateral view, reaching slightly more than halfway along outer ramus of uropod 3, length/ dorsal width 2.4, with row of 3 robust setae, small simple setae and single plumose seta dorsally on each lobe, apices with 1 long and 1 short robust seta.

Male. Generally as female but differing as follows: Antenna 1 flagellum proximal half of article 1 with ventral row of about 20 long aestetascs in apparently single field callynophore, assessory flagellum of 3 articles, as long as article 1 of flagellum. Antenna 2 peduncle articles 3–5 with dorsal row of simple, equal sized setae, flagellum of antenna 2 of 7+ articles. Gnathopods 1 and 2 basis less setose. Uropods 1 and 2 rami with longer robust setae.

Size. Largest ♀, 7.0 mm. Largest ♂, 6.7 mm.

Distribution. Australia, Bass Strait and eastern slope; 200–600 m (1000 m, 1 small juvenile).

Figures

FIGURE 27. Glandulotiron bassianus gen. et sp. nov. Holotype, ♀. clv, head lateral view; c and ant lv, head and antennae lateral view; mx1, maxilla 1; tel, telson; us, urosome.

FIGURE 28. Glandulotiron bassianus gen. et sp. nov. Holotype, ♀. l gp1, left gnathopod 1; r gp1, right gnathopod 1; gp2, gnathopod 2 (dactylus broken); p3, pereopod 3; p5–p7, pereopods 5 to 7.