Notopais minya, Merrin, Kelly L., 2004

Merrin, Kelly L., 2004, Review of the deep­water asellote genus Notopais Hodgson, 1910 (Crustacea: Isopoda: Munnopsididae) with description of three new species from the south­western Pacific, Zootaxa 513, pp. 1-27 : 13-21

Notopais minya n. sp. ( Figs 4–7 )

Material examined.— All material from eastern Australia. Holotype. Ovigerous female (5.0 mm), Stn SLOPE 56, 44 km E of Nowra, NSW, from 34º55.79’S 151º08.06’E to 34º56.06’S 151º07.86’E, 22 October 1988, WHOI epibenthic sled, muddy coarse shell, 429–466 m, G.C.B. Poore et al., R.V. Franklin ( NMV J52877 ). Paratypes. 69 males, 91 females, 9 fragments (between 2.0– 5.5 mm; 1 male, 3 mm and 2 females, 4.0 mm and 4.5 mm, dissected), type locality ( NMV J52876 ).

Additional material.— 2 males, 2 females, 2 fragments, 79­K­1 Stn 32, shelf, eastern Bass Strait, 39º41.7’S 148º39.5’E, 27 March 1979, dredge, muddy sand, 115 m, G.C.B. Poore, HMAS Kimbla ( NMV J18851 ). 4 males, 5 females, 1 fragment, Stn SLOPE 2, off Nowra, NSW, 34º57.9’S 151º8.0’E, 14 July 1986, WHOI epibenthic sled, in bryozoa and shell, 503 m (bottom), G.C.B. Poore et al., R.V. Franklin ( NMV J18847 ). 2 females, Stn SLOPE 19, off Eden, NSW, 37º07.3’S 150º20.2’E, 20 July 1986, WHOI epibenthic sled, grey coarse shell, 520 m (bottom), G.C.B. Poore et al., R.V. Franklin ( NMV J18848 ). 1 female, Stn S05/84/64, 15 km E of Cape Connella, Tas, 43º24.6’S 147º32.5’E, 22 October 1984, WHOI epibenthic sled, 82 m, R. Wilson, R.V. Soela ( NMV J18874 ). 1 female, 79­ K­1 Stn 33, Flinders Canyon, eastern Bass Straight, 39º40.3’S 148º46.5’E, 27 March 1979, dredge, coarse shell, 293–329 m, G.C.B. Poore, HMAS Kimbla ( NMV J18852 ). 2 males, 4 females, 3 fragments, Stn SLOPE 1, off Nowra, NSW, 34º59.52’S 151º5.94’E, 14 July 1986, WHOI epibenthic sled, coarse shell, 204 m (bottom), G.C.B. Poore et al., R.V. Franklin ( NMV J18846 ). 1 female, Stn SO 5/84/29, Tasman Sea, eastern slope, 70 km S of Gabo Island, Vic, 38º10.3’S 149º57.2’E, 14 October 1984, WHOI epibenthic sled, 592 m, R. Wilson, R.V. Soela ( NMV J18854 ). 1 female, Stn SO 5/84/30, Tasman Sea, eastern slope, 50 km S of Mallacoota, Vic, 38º06.2’S 149º45.5’E, 14 October, 1984, WHOI epibenthic sled, 188 m, R. Wilson, R.V. Soela ( NMV J18855 ). 2 males, 7 females, 6 fragments, Stn SLOPE 40, south of Point Hicks, Vic, 38º17.7’S 149º11.3’E, 24 July 1986, WHOI epibenthic sled, coarse sand, gravel and mud, 400 m (bottom), M.F. Gomon et al., R.V. Franklin ( NMV J18849 ). 3 males, 4 females, 79­K­1 Stn 35, shelf, eastern Bass Straight, 39º28.4’S 148º41.8’E, 28 March, 1979, dredge, shell and sand, 110 m, G.C.B. Poore, HMAS Kimbla ( NMV J18853 ).

Description: Holotype. Body 2.5 times as long as greatest width (from spine to spine) of pereonite 2; widest at pereonite 3; cuticle not highly calcified, lightly setose. Cephalon lightly setose with 4 spines; anterior margins with few small, simple setae; posterolateral margins broadly rounded; ridge encompassing antennae, with no extension. Pereonite 1 anterior margin with 4 well developed spines, pereonites 2 and 3 with 6 and pereonite 4 with 5; pereonite 5 anterior margin rounded; anterolateral margins of pereonites 6 and 7 with small lobes, facing anteriorly.

Paratypes. Antenna 1 of 13 articles; article 1 distal end rounded, concave in centre, 1.1 times as long as wide, inferior margin with 1 simple and 1 flagellate robust seta, medial surface with 2 simple setae, 1 broom seta and 4 flagellate robust setae, superior margin with 5 simple seta and 1 robust seta (broken); article 2 elongate, 0.5 times as long as article 1, 1.9 times as long as wide, with 2 robust flagellate setae and 4 broom setae; remaining articles all rectangular; article 4 with 2 broom setae; article 5 with 1 simple seta; from article 6 onwards, each article has 1 aesthetasc, many articles having additional simple setae; terminal article with 1 small simple seta and 1 broom seta. Male antenna 1 similar, of 22 articles; article 1 and 2 ratios similar to female, article 1 superior margin with 3 robust flagellate setae (1 long, 2 short) and 1 broom seta (in clump with robust flagellate setae), distal margin with 3 robust flagellate setae and 1 broom seta; article 2 1.6 times as long as wide, distal margin with 3 robust flagellate setae and 3 broom setae; article 5 with 2 broom setae; from article 8 onwards each article has 1 aesthetasc and many having additional simple setae. Antenna 2 articles 1–3 more or less triangular; article 1 superior margin with 3 additional robust flagellate setae; article 2 0.6 times as long as article 1, with 3 simple seta; article 3 0.6 times as long as article 1, with 1 simple seta and 9 flagellate robust setae (3 broken), all around lateral angled rim of article; article 4 small, 0.8 times as long as article 1, with no ornamentation; article 5 4.6 times as long as article 1, inferior margin with 1 simple seta (proximal end), 6 robust setae (evenly spaced), 2 long robust setae (at midpoint) and mesial face with 4 robust setae, 3 robust flagellate setae and 1 broom seta (at distal end), superior margin with 7 robust setae and 2 flagellate robust setae, distal margin with 8 blunt robust setae; article 6 10.3 times as long as article 1, inferior margin with 14 robust setae, 2 robust flagellate setae, 2 broom setae (distal) and 4 long robust setae, mesial face with 9 robust setae, 2 robust flagellate setae and 2 long robust setae, superior margin with 9 robust setae, 2 robust flagellate setae, 2 broom setae (distal), distal margin with 4 robust flagellate setae and 3 robust setae; flagellum of 33 articles (present, flagellum not complete), each setose.

Left and right mandible identical; mandible without microtrichs; spine row absent; molar small, terminated with 3 uni­serrate setae and 2 simple setae. Maxilla 1 lateral lobe 1.9 times as wide as mesial lobe, lateral and mesial margins with fine simple setae, distal margin with numerous simple setae, 5 robust setae, 3 robust dentate setae and 4 robust semi­plumose setae; mesial lobe with fine simple setae on margins, terminated with 15 simple setae and 2 long pectinate setae. Maxilla 2 lateral lobe with scattered fine simple setae, distally with 1 smaller and 4 long simple setae; middle lobe 1.1 times as wide as lateral lobe, distally with 4 long simple setae and 1 smaller simple seta; mesial lobe 3.4 times as wide as lateral lobe, margins with fine simple setae, terminated with 14 simple setae, 5 toothed setae and 1 long pectinate seta. Maxilliped coxa rectangular, small, 0.9 times as long as wide, 0.3 times as long as basis (including endite); basis elongate, length including endite 2.6 times as wide, with 5 simple setae (proximal); endite with 5 coupling hooks, and distally with 3 simple setae, 3 toothed setae, 6 fan setae (5 small, 1 large), and many fine simple setae; palp wider proximally, tapers distally, article 1 wide, rectangular, shortest, 0.1 times as long as basal endite, anterolateral margin with 1 simple seta, anteromesial margin with 1 simple seta; article 2 5.1 times as long as, and 1.6 times as wide as article 1, and 1.6 times as wide as basal endite, superior margin with 9 simple setae (evenly spaced), and inferior margin with 4 simple setae (distal end); article 3 2.7 times as long as, and 0.9 times as wide as article 1, with 1 simple seta on superior margin (distal), inferior margin with 12 simple setae, and 17 semi­fan setae; article 4 almost rectangular, 1.6 times as long as, and 0.5 times as wide as article 1, superior margin with 1 simple seta (distal), and distal margin with 7 simple setae (inferior side); article 5 rectangular, small, narrowest of all articles, 1.3 times as long as, and 0.2 times as wide as article 1, with 6 terminal simple setae; epipod elongate, 1.8 times as long as wide, and 1.1 times as long as basis length, with many microtrichs on margin.

Pereopod 1 basis 6.5 times as long as wide, inferior margin with 9 setae (all SS), lateral face with 3 setae (all distal RFS), superior margin with 8 setae (all SS); ischium 4.3 times as long as wide, inferior margin with 2 setae (both SS), lateral face with 22 setae (all SS, scattered); merus 0.8 times as long as wide, inferior margin with 19 setae (all SS, of varying lengths, scattered), distosuperior margin with 5 setae (all SS); carpus 5.0 times as long as wide, inferior margin with 5 setae (long SS, proximal half), superior margin with 4 setae (all SS, 1 at midpoint, 3 at most distal corner); propodus 9.8 times as long as wide, inferior margin with 14 setae (all SS, in distal half), lateral face with 3 setae (all SS, in distal half), superior margin with 3 setae (all SS, in distal corner); dactylus 4.5 times as long as proximal width, superior margin with 4 setae (all SS, on distosuperior margin).

Pereopod 5 basis 3.4 times as long as wide, inferior margin with 18 setae (16 SS, 3 on distal corner, 2 proximal, sub­marginal RFS), lateral face with 13 setae (12 scattered SS, 1 RFS at distal end), superior margin with 8 setae (2 SS and 6 RFS, all in distal half); ischium 2.4 times as long as wide, inferior margin with 13 setae (all SS, 6 marginal, 7 sub­marginal), lateral face with 12 setae (all SS), superior margin convex, with 6 setae (5 submarginal SS, 1 distal SS); merus 0.9 times as long as wide, inferior margin with 22 setae (all SS, of varying lengths); carpus 3.6 times as long as wide, lateral face with 14 setae (all SS, scattered), superior margin with 1 seta (RFS, distal corner); propodus slightly expanded, 3.6 times as long as wide, inferior margin with 4 setae (all SS, 2 on distal margin, 2 sub­marginal), superior margin with 12 setae (10 sub­marginal SS, 1 long SS and 1 BS on distal corner); dactylus 6.3 times as long as proximal width, with 12 setae (all SS, all but 3 on superior margin).

Pereopod 6 basis thicker compared with basis in pereopod 5, 3.4 times as long as wide, inferior margin with 30 setae (25 RFS, 4 PLS, 1 distal SS), lateral face with 1 seta (distal SS), superior margin with 3 setae (all SS); ischium similar to that of pereopod 5, although 2.2 times as long as wide, inferior margin with 17 setae (all SS, 11 marginal, 6 sub­marginal), superior margin with 4 setae (all SS, sub­marginal in distal half); merus distosuperior margin cup­shaped, with carpus inserted into it, length 0.8 times as long as wide, inferior margin with 19 setae (all SS, of varying lengths); carpus similar to that of pereopod 5, 1.2 times as long as wide, lateral face with 18 setae (all SS, scattered); propodus similar although more elongate than in pereopod 5, 4.4 times as long as wide, also inferior margin with 3 setae (all SS), superior margin with 12 setae (all SS); dactylus similar to that in pereopod 5, although 9.3 times as long as proximal width, with 13 setae (all SS, all but 3 on superior margin).

Pereopod 7 basis 4.6 times as long as wide, inferior margin with 21 setae (17 RFS, 1 proximal PLS, 3 distal SS), superior margin with 5 setae (3 short SS, 2 PLS at proximal end); ischium 2.5 times as long as wide, inferior margin with 14 setae (all SS), superior margin with 9 setae (all sub­marginal SS); merus 1.1 times as long as wide, inferior margin with 18 setae (all SS, of varying lengths), distosuperior margin with 2 setae (both SS); carpus 2.8 times as long as wide, inferior margin with 11 setae (all sub­marginal SS), superior margin with 13 setae (12 sub­marginal SS, 1 RFS at distal corner); propodus 8.6 times as long as wide, superior margin with 13 setae (11 sub­marginal, evenly spaced SS, distal corner with 1 long SS and 1 BS); dactylus 8.5 times as long as proximal width, with 14 setae (all SS, scattered along superior margin).

Pleon 0.9 times as long as proximal width, posterior tip rounded, with scattered simple setae. Male pleopod 1 2.9 times as long as proximal width, lateral margins indent 0.3 from proximal end, either side of centre margin with 17 simple setae (9+8), distally with pair of lobes which go over distolateral horns, with 29 simple setae (14+15). Male pleopod 2 sympod 2.5 times as long as wide, superior margin with 1 simple seta and 15 plumose setae, lateral surface with 16 simple setae (scattered), distal margin with 2 plumose setae and fringe of fine setae; exopod elongate and oval, length 0.1 times as long as sympod; stylet 0.3 times as long as sympod, terminating to a point, sperm duct 0.2 times as long as stylet. Operculum large, 1.8 times as long as proximal width, distally with medial slit and veined lamellar extension, median keel provided with a row robust and simple setae, distal surface with 14 plumose setae (7+7) and entire face with scattered simple setae of varying lengths, lateral margins with numerous plumose setae. Pleopod 3 exopod narrowing, 1.0 times as long as endopod, with row of fine simple setae and distally with 6 long plumose setae; endopod 1.7 times as long as wide, endopod with 8 long plumose setae. Pleopod 4 exopod slender, shorter than endopod, with its distal point at 0.7 times length of endopod, superior and inferior margin (part) with fringe of fine simple setae, with 4 terminal long plumose setae; endopod oval, 1.4 times as long as wide. Pleopod 5 1.8 times as long as wide.

Uropod protopod elongate, 2.3 times as long as wide, margins subparallel, distal end rounded, smooth, lateral margin with 19 plumose setae (4 broken) and 20 simple setae, mesial margin with 5 plumose setae, surface with 17 scattered simple setae; exopod small, 0.1 times as long as protopod and 0.4 times as long as endopod, with 3 simple setae; endopod 0.3 times as long as protopod, with 4 simple and 4 broom setae.

Remarks: Notopais minya n. sp. shows some resemblance to N. magnifica although it does not have as many spines on its first four pereonites as has N. magnifica . N. minya also has only 4 small spines on its cephalon instead of the 2 large dorsal and 2 smaller ones seen on the anterolateral angles of N. magnifica . N. minya also has a unique setation pattern on the first four articles of antenna 2. Unlike all other Notopais described in this paper, article 2 has no distolateral spine. Pereonites 5–7 are similar to that of N. beddardi , except the anterolateral margins on pereonite 6 are more acute.

Distribution: South­eastern Australia, from Nowra, New South Wales to Eastern Bass Strait, depths from 110–592 metres.

Etymology: Minya is an Aboriginal word meaning small.

Figures

FIGURE 4. Notopais minya n. sp. A, B, female holotype, 5.0 mm; C and E, female paratype, 4.0 mm; D, male paratype, 4 mm. A, dorsal view; B, lateral view; C, left antenna 1; D, right antenna 1; E, right antenna 2.

FIGURE 5. Notopais minya n. sp. All figures from female paratype. A, left mandible; B, left mandibular molar (top) and right mandibular molar (bottom); C, right maxilla 1; D, left maxilla 2; E, left maxilliped; F, left pereopod 1; G, right pereopod 7.

FIGURE 6. Notopais minya n. sp. All figures from female paratypes, operculum only from female paratype 4.5 mm. A, left pereopod 5; B, right pereopod 6; C, operculum; D, left pleopod 3; E, left pleopod 4.

FIGURE 7. Notopais minya n. sp. A, D and E, female paratype; B, C, male paratype. A, left pleopod 5; B, pleopod 1; C, left pleopod 2; D, left uropod; E, enlargement of distal part of left uropod.