Glandulotiron concavus, 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 : 42-45

Glandulotiron concavus sp. nov.

( Figs 23–24 )

Type fixation. Holotype, ♀.—Here designated.

Etymology. The species is named for the concavity of the interantennal head lobe.

Material examined. Holotype, ♀, 10.6 mm. Australia, Tasmania, Western Bass Strait, 15 km S of Port Fairy, 38˚32.00’S, 142˚28.36’E, 52 m, medium sand, R. Wilson , 20 November 1981, RV Tangaroa , stn BSS187 , NMV J72716 .

Paratypes. Same data as holotype, NMV J75154 (1 ♂) . Australia, Tasmania, Central Bass Strait, 35 km NNE of Cape Wickham, King Island , 39˚16.00’S, 144˚05.24’E, 82 m, sandy shell, S-M grab, R. Wilson, 23 November 1981, RV Tangaroa , stn BSS204 , NMV J73713 (1 ♀) . Australia, Victoria, Western Bass Strait , 55 km SW of Cape Otway, 39˚16.42’S, 143˚06.42’E, 95 m, medium sand, rock dredge, R. Wilson, 21 November 1981, RV Tangaroa , stn BSS193 , NMV J73719 (1 ♀) . Australia, Tasmania, Eastern Bass Strait, 63 km E of North Point, Flinders Island , 39˚40’48’’S, 148˚49’36’’E, 124 m, muddy sand, 14 November 1981, RV Tangaroa , stn BSS167 , NMV J73721 (3 specimens) . South Australia, St Francis Island, Nuyts Archipelago, off Ceduna , 32˚30’S 133˚17’E, NMV J73755 (1 ovigerous ♀) . Australia, Tasmania, Western Bass Strait, 59 km WNW of Cape Farewell, King Island , 103 m, coarse sand, pipe dredge, G.C.B. Poore, 20 October 1980, HMAS Kimbla , stn BSS81 , NMV 73756 (1 specimen) . Australia, Victoria, Western Bass Strait , 80 km WSW of Cape Otway, 39˚59’S, 142˚37’E, 94 m, coarse sand, S-M grab, G.C.B. Poore, 9 October 1980, HMAS Kimbla , stn BSS62 , NMV J73762 (1 specimen) . Australia, Victoria, Eastern Bass Strait , 28 km SSW of Marlo, 37˚59’00’’S, 148˚27’00’’E, muddy sand with fine shell, 30 July 1983, stn BSS 207 , NMV J73764 (1 ♀) . Australia, Tasmania, Central Bass Strait, 23 km E of Cape Rochon, Three Hummock Island , 40˚22’12’’S, 145˚17’00’’E, 40 m, sand, epibenthic sled, G. Poore et al., FV Sarda , stn BSS112 , 3 November 1980, NMV J73765 (1 ♂) . Australia, Tasmania, Western Bass Strait, 59 km WNW of Cape Farewell, King Island , 39˚28’S, 143˚17’E, 103 m, coarse sand, pipe dredge, G.C.B. Poore, 20 October 1980, HMAS Kimbla , stn BSS81 , NMV J73769 (1 ♀) . Australia, Tasmania, Central Bass Strait, 35 km N of Cape Wickham, King Island , 39˚13.36’S, 143˚55.36’E, 85 m, R. Wilson, 23 November 1981, RV Tangaroa , stn BSS205 , NMV J73775 (1 ♀) . Australia, Tasmania, Western Bass Strait, 59 km WNW of Cape Farewell, King Island , 39˚28’S, 143˚17’E, 103 m, coarse sand, pipe dredge, G.C.B. Poore, 20 October 1980, HMAS Kimbla , stn BSS81 , NHMD 916113 (1 ♀) .

Description (female). Rostrum with broadly rounded apex. Interantennal lobes broad, concave between rounded corners. Accessory eye composed of 5 appressed ommatidia.

M outhparts. Maxilla 1 palp with 6 medium sizes unidentate robust setae and single lateral elongate serrate robust seta; outer plate with row of 9 dentate robust setae. Mouthparts otherwise normal.

Antennae 1 as long as pereonite 1–5 and half of 6 combined along dorsum, peduncle article 2 about 0.6 length of 1, article 3 length 2/3 of 2, article 1 with a few dorsal and ventral penicillate seta; flagellum as long as peduncle, of 9+ articles; accessory flagellum of 4 articles. Antenna 2 as long as pereonites 1–6 and 1/3 of 7 combined along dorsum, peduncular article 4 the longest, flagellum of 7 articles, all articles except small terminal one with single slender robust seta distally, antenna otherwise sparsely setulose.

Coxal plates 1–2 rounded apex fringed with long setae; plate 3 obliquely truncate distally, crenulate with variously long setae, plate 4 broadly rounded with a few short setae.

Gnathopod 1 carpus with long setae on mid-anterior margin; propodus with 5–6 pectinate setae on posterior margin. Gnathopod 2 carpus with a few mid-anterior setae. Both gnathopods with 12–14 groups of unequally long setae along posterior margin of carpus.

Pereopods 3–4 basis sparsely setose. Pereopods 5–7 basis with posterodistal rounded projection; pereopod 5 and 6 basis broadest distally; pereopod 5 basis with concave posterior margin, pereopod 6 posterior margin straight, pereopod 7 broadest proximally, posteroproximal expansion broadly rounded, posterior margin broadly convex crenulate with tiny setules in indentations. Pereopods 6 and 7 with long setae in submarginal row on medial surface.

Uropod 1 peduncle reaching to end of peduncle of uropod 2, rami of equal length, about 2/3 length of peduncle, reaching beyond end of rami of uropod 2 with 1/5 of its length, outer ramus with 3 short dorsal robust setae, inner ramus with 3 long dorsal robust setae. Uropod 2 outer ramus slightly shorter than inner ramus; inner ramus peduncle and outer ramus both with 4 short dorsal robust setae; inner ramus with 3 long robust setae. Both uropods 1 and 2 reaching barely halfway along outer ramus of uropod 3. Uropod 3 peduncle about 2/3 length of outer ramus, outer ramus basal article with row of 9 robust setae dorsolaterally, and 5 very small robust setae ventrolaterally, small second article with 3 dorsal robust setae; inner ramus reaching to 4/5 of basal article of outer ramus, dorsal margin with row of long setae and 2 robust setae, apex with 3 robust setae.

Telson. Length/width 2.0, reaching 0.5 along outer ramus of uropod 3, with row of 4–5 robust setae, a number of small simple setae and a few short plumose setae on each lobe, 1 long and 1 short robust seta apically at each lobe.

Male. Generally as female except for sexual characters of the antennae.

Size. Largest ♀, 10.6 mm, ovigerous. Largest ♂, 8.4 mm.

Distribution. Australia, Bass Strait, 52– 103 m.

Figures

FIGURE 23. Glandulotiron concavus gen. et sp. nov. Holotype, ♀, except M, ♂ paratype. clv, head, lateral view; mx1, maxilla 1; tel, telson; us, urosome; x, concave interantennal lobe.

FIGURE 24. Glandulotiron concavus gen. et sp. nov. Holotype, ♀. cox4, coxal plate 4; gp1, gnathopod 1; gp2, gnathopod 2; p3, pereopod 3; p5–7, pereopods 5 to 7.