Belkginoecetes darwiniense, Just, Jean, 2012

Just, Jean, 2012, Siphonoecetini Just, 1983 (Crustacea, Amphipoda, Ischyroceridae) 10: Belkginoecetes gen. nov., Tropicoecetes gen. nov. and Rhinoecetes Just, 1983 from north-eastern and northern Australian shallow water, with eight new species, Zootaxa 3528, pp. 1-28 : 15

Belkginoecetes darwiniense sp. nov.

Figures 10 –11

Type fixation. Holotype, male, here designated.

Etymology. The epithet alludes to the Capital City of the Northern Territory, Darwin.

Material examined. Holotype, 3, 3.3 mm, Bullocky Point, Fannie Bay, Darwin Harbour, Northern Territory, Australia, 12°26’S, 130°49’E, 1.5 m (LW), just outside low reef, muddy sand with fine shell fragments, scattered Halodule , hand dredge. J. Just, 18 August 1984, stn AU41, MAGNT Cr004024.

Paratypes. Same data as holotype, MAGNT Cr004025 (20 specimens including ovigerous ƤƤ, many abodes). South side of North Shell Island, Darwin Harbour, Northern Territory, Australia, 12°29’S, 130°54’E, 0.5 m (LW), muddy sand and shell fragments, hand dredge, J. Just, 30 August 1984, stn AU51, MAGNT Cr004026 (2 ovigerous Ƥ, 1 Ƥ, 22 abodes, some occupied). Between North Shell Island and mainland, Darwin Harbour, Northern Territory, Australia, 12°29’S, 130°54’E, north of LW-connection, 0.2 m (LW), muddy sand between rock, coral, gorgonians, hydroids, hand dredge, J. Just, 30 August 1984, stn AU52, MAGNT Cr004027 (1 small specimen). Bullocky Point, Fannie Bay, Darwin Harbour, Northern Territory, Australia, 12°26’S, 130°49’E, 1 m (near LW), just outside low reef, muddy sand with fine shell fragments, scattered Halodule , hand dredge, J. Just, 1 September 1984, AU53, MAGNT Cr004028 (1 ovigerous Ƥ, 1 young, 8 abodes, some occupied). Bullocky Point, Fannie Bay, Darwin Harbour, Northern Territory, Australia, 12°26’S, 130°49’E, 0.5 m (near LW), inside low reef, mud with some fine sand and shell fragments, hand dredge, J. Just, 1 September 1984, stn AU54, MAGNT Cr004029 (1 ovigerous Ƥ, 1 young, 3 abodes). Inside Old Man Rock, Casuarina Beach, Fanny Bay, Darwin Harbour , Northern Territory, Australia, 12°21’S, 130°52’E, 0.5m (near LW), fine mineral sand, some mud and detritus, scattered Syringodium , hand dredge, J. Just, 31 August 1984, stn AU55, MAGNT Cr004030 (1 abode). Lee Point, Darwin Harbour, Northern Territory, Australia, 12°20’S 130°54’E, 1.5m (LW), very coarse shell and coral sand with some detritus and mud, patches between rocks and corals, hand dredge. J. Just, 29 August 1984, stn AU50, ZMUC-CRU- 20532 (13, 3 ovigerous Ƥ, 2 young, 7 abodes).

Description (holotype, 3). Head as long as pereonites 1 and 2 and 1/3 of 3 combined along dorsal midline. Rostrum slightly down curved in lateral view, acutely pointed; in dorsal view reaching beyond apices of eye lobes with about 1/2 its length. Eye lobes truncate in lateral view, broadly rounded in dorsal view, lower anterior margin with single simple seta.

Antenna 1 as long as head and pereonites 1–5 combined, barely reaching apex of antenna 2 peduncle article 4; flagellum of 5+ articles, approximately as long as peduncle articles 2 and 3 combined. Antenna 2 as long as entire body from tip of rostrum to insertion of telson ; ventral projection of peduncle article 2 base width 2/3 greatest length, margins nearly parallel, rounded distally, with fringe of long setae laterally and apically; articles 3–5 with dorsal, ventral and lateral groups of short simple setae; article 5 length 0.9 of 4; flagellum articles 1 and 2 with short, backward curved robust setae on medial margin, article 2 with single robust seta distally on lateral margin.

Mouthparts, mandible palp article 1 with 2 long dorsal, 2 shorter ventral and 3 terminal long setae.

Gnathopod 1 propodus length 3.0 width, with 2 midposterior robust setae. Gnathopod 2 propodus length 2.0 greatest width. Pereopods 3–4 basis with open row of long and very short setae on anterior margin, 2 long setae on lateral surface, tuft of long setae on midposterior margin; merus with single midanterior group of long and short setae, with groups of long setae along posterior margin. Pereopods 5–6 basis with 2 groups of long setae on anterior margin, posterior margins with single group of long setae.

Uropod 1 peduncle with 2–3 small dorsolateral robust setae; outer ramus 3.7 times longer than wide, approximately 0.5 length of peduncle, lateral margin with 2 robust setae, dorsally with single simple seta (on left uropod developed as small robust seta); inner ramus 0.9 length of outer ramus, slightly tapering towards apex. Uropod 3 barely reaching beyond telson , distolaterally with 2 long simple setae, mediodistally with 2 short simple setae. Telson width 1.35 length, apex slightly convex.

Female. Antenna 1 with 4+ flagellar articles. Uropod 1 peduncle and outer ramus with 4 and 5 robust setae respectively. Pereonite 7 ventrally with short, broadly rounded sternal papillae (Fig. 11 Fsp).

Size. Largest 3, 3.3 mm, largest Ƥ, 3.4 mm.

Colour and biology. Body faintly brownish to light sandy mottled; brownish pigment on pereonite 1 and coxae 1 and 2 also include entire gnathopods 1 and 2. Antenna 1 red-brown. Specimens mostly occupy microprosobranch shells and occasionally polychaete tubes.

Distribution. Darwin Harbour, Northern Territory, Australia; 0.2–1.5 m at low water.

Figures

FIGURE 10. Belkginoecetes darwiniense gen. et sp. nov. Holotype, 3, except M, paratype 3 and F, paratype Ƥ. a 2 flag, antenna 2 flagellum; c dv and c lc, head dorsal and lateral view; md plp, mandible palp; us, urosome. Habitus scale: 1 mm.