Notopais zealandica, 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 : 21-26

Notopais zealandica n. sp. ( Figs 8–10 )

Material examined.— Holotype. Female (4.5 mm), Stn S150, Chatham Rise, New Zealand, 45º46.0’S 174º24.5’E, 26 October 1979, epibenthic sled, 1640 m, R.V. Tangaroa ( NIWA 3303). Paratypes. 1 male (3.0 mm, part remaining only, pleon missing), 5 females (3.5 [dissected], 3.5, 4.0, 4.5 [dissected], 4.8 mm), Stn S153, Chatham Rise, New Zealand, 45º21.1’S 173º35.8’E, 27 October 1979, epibenthic sled, 1386 m, R.V. Tangaroa ( NIWA 3304).

Additional material.— 2 fragments, Stn S153, Chatham Rise, New Zealand, 45º21.1’S 173º35.8’E, 27 October 1979, epibenthic sled, 1386 m, R.V. Tangaroa ( NIWA 3331).

Description: Holotype. Body 2.1 times as long as width of pereonite 2 (from spine to spine), widest at pereonite 5; cuticle not highly calcified, smooth. Cephalon smooth; anterior margins with few small, simple setae; posterolateral margins broadly rounded; antennal ridge with poorly developed extensions near antennal bases. Pereonites 1–5 anterior margins with stiff simple setae; pereonite 5 with anterolateral margins rounded and bladelike overhang raised above pereonites anterior margin; anterolateral margins of pereonites 6 and 7 with small anteriorly facing lobes.

Paratypes. Antenna 1 of 9 articles; article 1 rectangular, 1.6 times as long as wide, dorsal surface concave, inferior margin with 5 simple setae, mesial surface with 1 broom seta, distal margin with 5 robust setae, 2 flagellate robust setae and 1 broom seta; article 2 0.3 times as long as article 1, 1.8 times as long as wide (not including distal projection) with 2 robust setae, one on distal projection; remaining articles all rectangular; article 4 with 3 simple setae; article 6 with 1 distal aesthetasc; terminal article with 3 small simple setae. Antenna 2 articles 1–3 more or less triangular; article 2 1.1 times as long as article 1, with 1 robust flagellate seta on distosuperior margin and 1 simple seta; article 3 1.4 times as long as article 1, distal margin with 5 peripheral long robust and 1 flagellate robust seta; article 4 small, about half the size of article 3, 1.1 times as long as article 1, not ornamented.

Left and right mandible identical in structure; mandible spine row absent; molar small, terminated by 2 uni­serrate and 3 simple setae (left molar terminated with 4 uni­serrate setae). Maxilla 1 lateral lobe 2.1 times as wide as mesial lobe, lateral and mesial margins with fine simple setae, distal margin with 6 robust, 3 robust dentate and 3 robust semi­plumose setae; mesial lobe with fine simple setae on margins, terminated with 6 simple and 2 long pectinate setae. Maxilla 2 lateral lobe with scattered fine simple setae, distally with 4 long simple setae; middle lobe 1.2 times as wide as lateral lobe, distally with 3 long simple setae; mesial lobe 2.0 times as wide as lateral lobe, margins with fine simple setae, terminated with 7 simple setae, 4 toothed setae and 1 long pectinate seta. Maxilliped coxa rectangular, small, 0.8 times as long as wide, 0.2 times as long as basis (including endite); basis elongate 2.9 times as long as wide (including endite), with 2 simple setae, distal superior margin with 1 simple seta; endite with 4 coupling hooks, distally with 4 simple setae, 3 fan setae and many fine, simple setae; palp wide proximally distally narrow, article 1 wide, shortest, 2.0 times as long as basal endite, trapezoid, with 2 simple setae on anterolateral margin, anteromesial margin with 1 simple seta; article 2 3.1 times as long as and 1.4 times as wide as article 1, 2.0 times as wide as basal endite, with microtrichs on lateral margin, superior margin with 3 simple setae, lateral face with 1 simple seta, and inferior margin with 3 semi­fan setae and 1 simple seta; article 3 1.7 times as long as wide, and 0.9 times as wide as article 1, superior margin with 2 simple setae, inferior margin with 4 simple setae and 15 semi­fan setae; article 4 rectangular, 0.4 times as long as article 1, superior margin with 1 simple seta, distal margin with 1 simple seta and 3 semi­fan setae; article 5 rectangular, small, narrowest article, 0.8 times as long as, and 0.1 times as wide as article 1, with 5 terminal simple setae; epipod semi­oval, 2.1 times as long as wide, 1.2 times as long as basis, with numerous marginal microtrichs.

Pereopod 1 basis 6.3 times as long as wide, inferior margin with microtrichs and 6 setae (5 SS, 1 distal RFS), lateral face with 2 setae (both SS, distal), superior margin with 3 setae (all SS); ischium 3.5 times as long as wide, inferior margin with 4 setae (all SS), lateral face with 3 setae (2 RFS, 1 SS), superior margin with 5 setae (2 distal SS, 2 short RS, 1 long RS at midpoint); merus 1.2 times as long as wide, inferior margin with 5 setae (all SS), distosuperior margin with 3 setae (all SS); carpus 4.6 times as long as wide, inferior margin with 4 setae (all long SS, 2+2 on proximal half), superior margin with 5 setae (all SS, 2 in distal corner); propodus length 5.3 times as long as wide, inferior margin with 6 setae (all SS), lateral face with 8 setae (all SS, scattered), superior margin with 2 setae (both SS, in proximal half); dactylus 2.3 times as long as proximal width, superior margin with 4 setae (all SS).

Pereopod 5 basis 3.5 times as long as wide, inferior margin with 9 setae (3 RFS & 4 SS all in loose cluster, distal corner with 1 RFS and 1 SS); ischium 2.2 times as long as wide, inferior margin with 10 setae (9 SS, 1 sub­marginal SS); merus 1.2 times as long as wide, inferior margin with 7 setae (all SS); carpus 0.9 times as long as wide, lateral face with 2 setae (both SS), superior margin with 1 seta (RFS, distal corner); propodus slightly expanded, 2.6 times as long as wide, superior margin with 8 setae (7 sub­marginal SS, 1 BS on distal corner); dactylus 5.7 times as long as proximal width, with 4 setae (all SS, on distosuperior margin).

Pereopod 6 basis thicker compared with basis in pereopod 5, 3.5 times as long as wide, inferior margin with 16 setae (10 SS, grouped in 2+7+1, 1 sub­marginal distal RS, 5 RFS, grouped in 4+1 on distal margin); ischium similar as in pereopod 5, although 2.1 times as long as wide, inferior margin with 16 setae (11 evenly spaced, marginal SS, 5 sub­marginal SS); merus distosuperior margin cup­shaped, with carpus inserted into it, 1.3 times as long as wide, inferior margin with 5 setae (all SS); carpus similar to carpus of pereopod 5, except proximal end of superior margin is slightly more expanded, 0.9 times as long as wide, lateral face with 4 setae (all SS); propodus similar although more elongate than in pereopod 5, 2.8 times as long as wide, superior margin with 10 setae (all sub­marginal, evenly spaced SS); dactylus similar to that of pereopod 5, although 6.7 times as long as proximal width; unguis absent.

Pleon 0.5 times as long as proximal width and posterior tip rounded. Operculum large, 2.5 times as long as proximal width, distal end with medial slit and veined lamellar extension, proximal margin of median keel and keel itself provided with robust simple setae (proximal margin 7+8), distal surface with numerous scattered simple setae, anterior margins with 13 simple setae, 6 on right and 7 on left margin, lateral margins with numerous plumose setae. Pleopod 3 exopod distally narrow, 1.3 times as long as endopod, proximolateral margin with 6 simple setae set amongst continuous fine simple setae, distally with 4 long plumose setae; endopod 1.4 times as long as wide, with 6 long plumose setae. Pleopod 4 exopod slender, shorter than endopod, with its distal point at 0.7 times endopod length, superior margin smooth, with 1 apical long plumose seta; endopod sub­circular, 1.1 times as long as wide. Pleopod 5 1.5 times as long as wide.

Uropod protopod 2.6 times as long as wide, margins sub­parallel, distomesial angle produced, not extending past endopod, with 1 plumose and 1 simple seta, lateral margin with 8 plumose setae and 11 simple setae, mesial margin with 4 plumose setae, surface with 9 scattered simple setae; exopod small, 0.2 times as long as protopod and 0.6 times as long as endopod, with 3 simple setae; endopod 0.3 times as long as protopod with 1 simple seta.

Remarks: Notopais zealandica n. sp. is unique in that all pereonites lack anterior spines on their margins and instead are provided with stiff simple setae, similar to that seen on pereonite 5 of N. beddardi . N. zealandica is also the only species in this genus without spines on the cephalon, and it has a distinct blade­like extension raised above the anterior margin of pereonite 5.

Distribution: Chatham Rise, New Zealand.

Etymology: N. zealandica is named after New Zealand, as this species occurs within its waters.

Figures

FIGURE 8. Notopais zealandica n. sp. A, B, female holotype, 4.5 mm; C – H, female paratype, 4.5 mm. A, dorsal view; B, lateral view; C, left antenna 1; D, right antenna 2; E, right mandible; F, right mandibular molar (top) and left mandibular molar (bottom); G, right maxilliped; H, right maxilliped palp.

FIGURE 9. Notopais zealandica n. sp. A, B female paratype; C – E female holotype. A, right maxilla 1; B, right maxilla 2; C, right pereopod 1; D, left pereopod 5; E, left pereopod 6.

FIGURE 10. Notopais zealandica n. sp. All figures from female paratypes, operculum only from female paratype, 3.5 mm. A, operculum; B, left pleopod 3; C, left pleopod 4, D, left pleopod 5; E, left uropod.