Sinoecetes reni, Just, 2019

Just, Jean, 2019, Siphonoecetini Just, 1983 (Crustacea, Amphipoda, Ischyroceridae) 13: Western Australian species of Bubocorophiina in Rhinoecetes, Cephaloecetes, Sinoecetes, Borneoecetes and Pararhinoecetes gen. nov., Zootaxa 4554 (1), pp. 101-140 : 132-134

Sinoecetes reni sp. nov.

Figures 21–22

Type fixation. Holotype, ♂, here designated.

Etymology. This species is named for Dr. X.Q. Ren for his monumental works on the Amphipoda of China.

Material examined. Holotype, ♂, 3.5 mm. Western Australia , King George Sound, north of False Island, 35°00.7’S 118°10.1’E, 28 m, shelly sand, G.C.B. Poore and H.M. Lew Ton, stn SWA 53, 15 April 1984, NMV J9580 .

Paratypes. Same sample as holotype, NMV J73183 (48 specimens) . Same sample as holotype, NHMD- 233161 (5 specimens) . Australia, Bass Strait, 35 km N of Cape Wickham, King Island , 39°13.36’S, 143°55.36’E, 85 m, epibenthic sled, R.S. Wilson, 23 Nov 1981, stn BSS 205, NMV J9578 (1 ♂) . Australia, New South Wales, Twofold Bay, wharf at Munganno Point , 37°04’S 149°55’E, 10 m, small pipe dredge, S. Keable, A. Paul, L. Walker, 26 August 1985, AM P36306 (17 specimens) .

Description (♂). Head as long as pereonites 1 and 2 combined along dorsal midline. Rostrum absent. Pseudorostrum present on upper frons. Front margin entire, wide angled across pseudorostrum. Pseudorostrum straight but slightly down-turned in lateral view, acutely pointed; in dorsal view reaching beyond apices of eye lobes with entire visible length. Eye lobes in lateral view tapering towards broadly rounded apex, with single simple setae distoventrally.

Antenna 1 as long as head, pereonites 1–3 combined, flagellum of 5+ articles, approximately as long as peduncle articles 1 and 2 combined. Antenna 2 as long as head and pereon combined, peduncle article 4 and 5 with 10–12 bunches of long somewhat curling setae ventrally; article 5 length 0.8 of article 4; ventral projection of peduncle article 2 approximately 2.3 longer than wide at base [observed in slightly oblique view], tapering to irregularly truncate apex, with fringe of long setae laterally and apically; flagellum articles 1 and 2 with 3 and 4 slender, straight robust setae respectively.

Mouthparts, mandible palp article 1 with 5 long setae on lateral margin, 2 on medial margin, and 2 near base of article 2.

Gnathopod 1 propodus length 2.8 width, with 1 mid-posterior robust seta. Gnathopod 2 propodus length 1.8 greatest width. Pereopods 3–4 basis with long setae on anterior margin, 1 long setae on lateral surface, several long setae of varying length on posterior margin; merus anterior margin with a few setae in distal half and tuft of long setae apically, with scattered setae along distal half of posterior margin. Pereopods 5–6 basis anterior margin with a few setae in distal half and distoapical tuft of long setae, posterior margins with a few short setae.

Uropod 1 peduncle with dorsolateral row of 6 large robust setae, apex with row of curved setae, ventroapical corona finely fimbriate; outer ramus 3.2 times longer than wide, approximately 0.5 length of lateral margin of peduncle, lateral margin with 4 large robust setae, dorsal surface with 2 simple setae; inner ramus 0.7 length of outer ramus; terminal robust seta half length of ramus. Uropod 3 peduncle with short, rounded median projection with a few simple setae, ramus broad, rounded with 4 long setae. Telson width 1.3 length, apex straight.

Female. Generally as male. Eyelobes slightly more angular apically than in male; pereonite 7 ventrally with short, probably immature, sternal papillae about as long as wide at base, with rounded apex ( Fig. 22 Fsp).

Size. Largest ♂, 4.3 mm (Bass Strait), 3.5 mm (type locality); largest ♀, 3.75 mm.

Colour and biology. No information.

Distribution. Southern Australia from Albany in the west to Bass Strait in the east, 28– 85 m. Remarks. The many specimens from the type locality in King George Sound are consistent regarding all important general, male, or female characters. However, the single male from the Bass Strait in the south-east differs in one respect from the south-western material by possessing more than 1 robust seta on pereopod 1 propodus: 1 and 2 on the right and left respectively proximal to the larger mid posterior one. This specimen is also larger than any male from the type locality. The fact that no ovigerous females were found in the King George Sound material, although a number had developing oostegites, in conjunction with the very small sternal papillae found, suggest that the specimens from the type locality are subadult, and hence with less well developed pereopod 1 setae.

Figures

FIGURE 21. Sinoecetes reni sp. nov. Holotype, ♂, except F, paratype, ♀. a2 flag, antenna 2 flagellum; cdv, cephalon dorsal view; clv, cephalon lateral view; md plp rv, mandible palp right ventral view. Habitus scale: 1 mm.

FIGURE 22. Sinoecetes reni sp.nov. Holotype, Ƌ, except M, paratype, ♂, and F, paratype, ♀. gp1–2, gnathopods 1 and 2; p3, p5, pereopods 3 and 5; sp, sternal papilla (6–7, pereonites 6 and 7); up1, uropod 1 peduncle apex ventral view; us, urosome; vp, ventral projection of article 2 of antenna 2.