Rhinoecetes meridianus, Just, Jean, 2012

Just, Jean, 2012, Siphonoecetini Just, 1983 (Crustacea, Amphipoda, Ischyroceridae) 9: New species in Rhinoecetes Just, 1983, Cephaloecetes gen. nov. and Neoecetes gen. nov. from the south-eastern Australian shelf, Zootaxa 3234, pp. 1-42 : 25-29

Rhinoecetes meridianus sp. nov.

Figures 16 , 17

Type fixation. Holotype, female, here designated.

Etymology. The species is widespread in south-eastern Australia, hence meridianus (Latin for southern).

Material examined. Holotype. Ƥ, 5.4 mm, Victoria, Port Phillip Bay at Portsea, west side of jetty, 38 ° 19 ’S, 144 ° 43 ’E, 5 m, sand with much detritus and shell fragments, hand dredge on SCUBA, J. Just, 29 May 1984, stn AU 30, NMV J 62382 .

Paratypes. Australia, Victoria, Port Phillip Bay: Same data as holotype, NMV J 62054 (1 ovigerous Ƥ, 2 abodes). Same data as holotype, NMV J 62055 (1 3, 3 Ƥ, 5 juvenile, ca. 50 abodes, mainly micro prosobranchs). Same data as holotype, NMV J 62386 (1 ovigerous Ƥ, 1 abode). Same data as holotype, NMV J 621571 (1 3 with abode). Southern Port Phillip Bay, 38 °21.00’S, 144 ° 51.30 ’E, 9 m, Smith-McIntyre grab, G.C. Poore and S.F. Rainer, FV Melita, stn PPBES 985, 9 December 1971, NMV J 62380 (1 specimen). 37 °53.0’S, 144 ° 51.5 ’E, 8 m, sand, stn PPBES 901, 7 June 1971, NMV J 1369 (8 specimens). 37 °53.0’S, 144 D 48.3 ’E, 5 m, sand, stn PPBES 903, 18 February 1971, NMV J 1370 (2 specimens). 37 ° 55.3 ’S, 144 ° 49.8 ’E, 9 m, sand, stn PPBES 904, 7 June 1971, NMV J 1371 (60 specimens). 37 ° 55.3 ’S, 144 ° 53.3 ’E, 12 m, silt–clay, stn PPBES 905, 8 June 1971, NMV J 1372 (1 3, 1 juvenile). 37 ° 57.7 ’S, 144 ° 48.1 ’E, 9 m, sand, stn PPBES 908, 8 June 1971, NMV J 1374 (ca. 70 specimens). 38 °00.0’S, 144 ° 42.9 E, 7 m, sand, stn PPBES 912, 19 November 1971, NMV J 1375 (6 specimens). 38 °00.0’, 144 ° 46.3 ’E, 11 m, sand, stn PPBES 913, 10 June 1971, NMV J 1376 (70 specimens). 38 °02.3’S, 144 ° 14.3 ’E, 10 m, sand, stn PPBES 921, 10 June 1971, NMV J 1377 (ca. 60 specimens). 38 °02.3’S, 144 ° 44.7 ’E, 13 m, sand, stn PPBES 922, 10 June 1971, NMV J 1378 (7 specimens). 38 °04.7’S, 145 °06.9’E, 6 m, sand, stn PPBES 939, 18 February 1971, NMV J 1380 (8 specimens). 38 °07.0’, 144 ° 41.3 ’E, 2 m, sand, stn PPBES 944, 10 June 1971, NMV J 1381 (2 specimens). 38 °21.0’S, 144 ° 51.5 ’E, 9 m, sand, stn PPBES 985, 9 December 1971, NMV J 1386 (> 200 specimens). Hobson Bay, 8 m, stn PPBES 1226, 9– 11 March 1971, NMV J 1387 (2 specimens). Off Patterson River, 4m, stn PPBES 1234, 9– 11 March 1971, NMV J 1390 (1 3). Off Patterson River, 4 m, stn PPBES 1236, 9– 11 March 1971, NMV J 1391 (1 specimen). Off Patterson River, 8 m, stn PPBES 1244, 9– 11 March 1971, NMV J 1394 (33 specimens). Off Patterson River, 8 m, stn PPBES 1245, 9– 11 March 1971, NMV J 1395 (1 Ƥ). Off Werribee, 8 m, stn PPBES 1262, 9– 11 March 1971, NMV J 1398 (3 specimens). Off Patterson River, 8 m, stn PPBES 1264, 9– 11 March 1971, NMV J 1399 (4 specimens). 38 °02.3’S, 144 ° 41.3 ’E, 10 m, sand, stn PPBES 921, 10 June 1971, NMV J 61805 (1 specimen). 38 °02.3’S, 144 ° 41.3 ’E, 10 m, sand, stn PPBES 921, 10 June 1971, NMV J 61806 (ca. 100 specimens). 38 °07.0’S, 44 ° 44.7 ’E, 4 m, sand, stn PPBES 945, 16 November 1971, NMV J 62572 (48 specimens). 4 m, sandy sediment, stn PPBES 945 /1, 16 November 1971, AM P 30029 (45 specimens). 4 m, sandy sediment, stn PPBES 945 /3, 16 November 1971, AM P 30030 (ca. 150 specimens). 9 m, sandy sediment, stn PPBES 985 /3, 9 December 1971, AM P 30058 (> 100 specimens).

Western Port: Crib Point, 38 ° 21.15 ’S, 145 ° 15.08 ’E, 2 m, Smith-McIntyre grab, stn CPBS 00E, 5 April 1965, NMV J 1352 (23 specimens). Crib Point, 38 ° 20.58 ’S, 145 ° 13.21 ’E, 2 m, Smith-McIntyre grab, 1 April 1965, NMV J 1353 (3 Ƥ, 1 3). Crib Point, 38 ° 21.73 ’S, 145 ° 13.23 ’E, 3 m, Smith-McIntyre grab, stn CPBS 01S, 1 April 1965, NMV J 1354 (50 specimens). Crib Point, 38 ° 19.98 ’S, 145 ° 13.23 ’E, 2 m, Smith-McIntyre grab, stn CPBS 02N, 6 April 1965, NMV J 1355 (8 specimens). Crib Point, 38 ° 22.29 ’S, 145 D 13.41 ’E, 3 m, fine sand, Smith-McIntyre grab, stn CPBS 02S, 20 November 1965, NMV J 1356 (7 specimens). Crib Point, 38 ° 20.23 ’S, 145 ° 13.28 ’E, 5 m, fine sand, Smith-McIntyre grab, stn CPBS 11 N, 31 March 1965, NMV J 1358 (11 specimens). Crib Point, 38 ° 19.98 ’S, 145 ° 15.13 ’E, 2 m, mud and Zostera , Smith-McIntyre grab, stn CPBS 12 N, 16 March 1965, NMV J 1359 (6 specimens). Crib Point, 38 ° 22.31 ’S, 145 ° 15.46 ’E, 2 m, fine sand, Smith-McIntyre grab, 18 March 1965, NMV J 1360 (1 ovigerous Ƥ, 1 3). Crib Point, 38 ° 21.15 ’S, 145 ° 13.36 ’E, 9 m, sand and shell, Smith-McIntyre grab, 24 March 1965, NMV J 1361 (1 Ƥ). Crib Point, 38 ° 19.98 ’S, 145 ° 14.31 ’E, 16 m, sand, Smith-McIntyre grab, stn CPBS 40 E, 22 March 1965, NMV J 1362 (1 Ƥ, 1 juvenile). Crib Point, 38 ° 20.44 ’S, 145 ° 14.41 ’E, 13 m, sand, Smith-McIntyre grab, stn CPBS 42 N, 1 April 1965, NMV J 1363 (3 specimens). Crib Point, 38 ° 20.33 ’S, 145 ° 14.31 ’E, 13 m, sand, Smith-McIntyre grab, stn WBES 1725, 20 November 1973, NMV J 1364 (2 specimens). 38 ° 26.45 ’S, 145 ° 21.93 ’E, 6 m, Smith-McIntyre grab, stn WBES 1739, 26 November 1973, NMV J 1365 (8 specimens). 38 ° 25. 39 ’S, 145 ° 15.97 ’E, 5 m, sand, Smith-McIntyre grab, stn WBES 1750, 25 November 1974, NMV J 1368 (10 specimens). 38 ° 26.72 ’S, 145 °05.79’E, 9 m, sand, Smith-McIntyre grab, 25 November 1965, stn WPES 1743, NMV J 1367 (1 juvenile). Crib Point, 38 ° 19.81 ’S, 145 ° 14.31 ’E, 13 m, sand, Smith-McIntyre grab, 16 March 1965, stn CPBS 36 N, NMV J 19343 (12 specimens). Crib Point, 38 ° 19.98 ’S, 145 ° 13.23 ’E, 2 m, Smith-McIntyre grab, 6 April 1965, stn CPBS 02N, NMV J 62373 (12 specimens). Crib Point, 38 ° 20.44 ’S, 145 ° 14.41 ’E, 13 m, sand, Smith-McIntyre grab, 25 March 1965, stn CPBS 42 N, NMV J 62374 (1 Ƥ, 1 young).

Wilsons Promontory: 39 °02.00’S, 146 °28.00’E, 13 m, muddy sand, stn WPPNPA 42, 9 February 1982, NMV J 9577 (20 specimens).

Bass Strait: Western Bass Strait, 40 °05.6’S, 143 ° 18.1 ’E, 123 m, medium sand, dredge, G.C.B. Poore, HMAS Kimbla , stn BSS98, 11 October 1980, NMV J 62375 (16 specimens). Western Bass Strait, 40 ° 41.8 ’S, 145 °07’S, 16 m, fine shelly sand, epibenthic sled, FV Sarda , stn BSS 110, 3 November 1980, NMV J 2637 (1 Ƥ). Western Bass Strait, 39 °49.0’S, 143 °24.0’E, 56 m, fine sand, epibenthic sled, stn BSS 184, 20 November 1981, NMV J 9573 (1 ovigerous Ƥ).

South Australia: Point Turton, Beach by jetty, fine sand, dredge, G.C.B. Poore and H.M. Lew Ton, stn SA22, 16 March 1985, NMV J 62377 (ca. 60 specimens).

Description (holotype, Ƥ). Head as long as pereonite 1 and 2 / 3 of 2 combined along dorsal midline; brows narrow; midanterior depression shallow, encompassing approximately 0.5 head length. Rostrum straight, in dorsal view slender, acutely triangular, about twice as long as broad at base, reaching beyond apices of eye lobes with about half its length. Eye lobes apically truncate in lateral view, lower anterior margin with a few short simple seta. Head and pereon with small simple setae in very short transverse rows on first 4 pereonites.

Antenna 1 approximately as long as head and pereonites 1–4 combined, reaching to proximal 1 / 4 of antenna 2 peduncle article 5; peduncles article 1 and 2 sparsely furnished with simple setae ventrally; flagellum of 7 + articles, approximately as long as peduncle articles 1 and 2 combined. Antenna 2 approximately as long as head and pereonites 1–6; ventral projection of peduncle article 2 approximately 1.4 as long as broad at base (base not fully observed), with broadly rounded apex, with fringe of simple setae apically and laterally; article 4 and 5 with spaced groups (some of single setae only) of irregularly long simple setae ventrally; article 5 length 0.8 of 4; flagellum articles 1 and 2 with long robust setae.

Mouthparts, mandible palp article 1 with a few dorsal, ventral and apical long setae.

Gnathopod 1 propodus length 3.0 width, with 3 posterior slender robust setae. Gnathopod 2 propodus length 1.7 greatest width. Pereopods 3–4 basis with scattered long and short setae along proximal half of anterior margin, 3–4 groups of long setae on posterior margin and single seta on distolateral surface; merus with 2 groups of short setae on mid anterior margin, 4–5 groups on posterior margin, and tuft of long and short setae on apex of anterior projection. Pereopods 5–6 basis, midanterior margin with a few unequally long setae, distal corner with tuft of long and short setae. Pereopod 7 propodus anterior margin with 2 groups of short setae in distal half and apical dense group of long setae. Sternal papillae mid ventral on pereonite 7, length approximately 1.6 width at base, nearly straight, tapering, pointing slightly backwards.

Uropod 1 peduncle with dorsolateral row of a few simple setae and single small simple seta in distomedial corner; outer ramus slender, inward curved, 0.5 length of peduncle, lateral margin with row of 4 robust setae, medial margin smooth; inner ramus 0.7 length of outer ramus, nearly straight, smooth except for apical robust seta. Uropod 2 peduncle 0.4 length peduncle of uropod 1, lateral margin with row of 3 simple setae; ramus 0. 5 length of peduncle, slender, straight, smooth except for apical robust seta, reaching to ramus uropod 3. Uropod 3 peduncle with rounded median projection carrying a few small simple setae; ramus with row of 5 unequally long setae, middle setae the longest. Telson width approximately 1.5 length, distal margin broadly rounded.

Male. Similar to female except the antenna 2 being stouter and more densely setose.

Size. Largest 3, 6.9 mm; largest ovigerous Ƥ 6.0 mm.

Variation. The rostrum varies in length, and some specimens have a considerably more down curved rostrum than shown in Fig. 16 .

Colour and biology. Entire dorsum to telson mottled in cream white and brown blotches; anterior quarter of head, rostrum and frons cream white; antenna 1 peduncle article 1 cream white, remaining parts densely brown; antenna 2 peduncle whitish with brown mottling in proximal parts of articles, flagellum colourless.

Abodes are comprised mainly of small micro prosobranchs furnished with a coarse tube of shell fragments.

Distribution. South-eastern Australis , Bass Strait, Port Phillip Bay to Adelaide, 2– 123 m.

Figures

FIGURE 16. Rhinoecetes meridianus sp. nov. Holotype, Ƥ, ovigerous, except M, paratype, 3, and A, paratype specimen in abode. a 2 flag, antenna 2 flagellum; c, head (dv, dorsal view, lv, lateral view). Habitus scale: 1 mm.

FIGURE 17. Rhinoecetes meridianus sp. nov. Holotype, Ƥ, except F, paratype, ovigerous Ƥ. gp 1 – 2, gnathopods 1 and 2; md plp, mandible palp; p 4 and 6, pereopods 4 and 6; pl 1, pleosome 1; pr 7, pereonite 7; sp, sternal papillae; us, urosome with uropods; vp, ventral projection of antenna 2 article 2.