Notopais quadrispinosa ( Beddard, 1886 ) Beddard, 1886

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 : 8-10

Notopais quadrispinosa ( Beddard, 1886) , comb. nov. ( Fig. 2 )

Ilyarachna quadrispinosa Beddard, 1886: 76 –78, pl. 12, figs 2–6.— Nordenstam, 1933: 266 –273, fig. 77.— Stephensen 1947: 8.— Wolff, 1962: 95.— Amar & Roman, 1974: 579.

Echinozone quadrispinosa .— Kussakin, 1967: 312.— Schultz, 1976: 4 –5.— Kussakin & Vasina, 1982: 326, fig. 29.— Brandt, 1990: 216 –218, fig. 1 (part).

Material examined.— Lectotype (here designated). Ovigerous female (6.0 mm), Station 149H, off Cumberland Bay, Kerguelen Island, southern Indian Ocean, 48º45’S 69º14’E, 29 January 1874, 127 fathoms (232 m), volcanic mud, HMS Challenger ( BMNH 1889.4.27.73).

Additional material.— Paralectotype (here designated). Female (pereonites 5–7 and pleon only, 2.0 mm) Station 149H, off Cumberland Bay, Kerguelen Island, southern Indian Ocean, 48º45’S 69º14’E, 29 January 1874, 127 fathoms (232 m), volcanic mud, HMS Challenger ( BHNM 2004.676).

Description: Lectotype. Body 2.4 times as long as greatest width (from spine to spine) of pereonite 2; widest at pereonite 3; cuticle not highly calcified, lightly setose. Cephalon smooth, with 2 dorsal spines; anterolateral margins each with 2 small spines and 1 small sub­marginal spine; posterolateral margins rounded; ridge encompassing antennae, with poorly developed extensions near first articles of antennae. Pereonites 1–3 and 5 anterior margins each with 4 well developed spines; pereonite 4 still with 4 well developed spines, but set back from anterior margin; pereonites 5–7 anterolateral margins pointing towards cephalon; pereonites 3 and 4 only with pair of lateral, sub­marginal spines; pereonites 1–4 each with pair of widely spaced, small, dorsal spines near lateral margins.

Antenna 1 of 11 articles (at least, number refers to what could actually be seen); article 1 distal end triangular, 1.5 times as long as wide, dorsal surface forms shallow depression, distal margin has 2 robust setae, superior margin with 3 simple setae (in proximal half) and 4 robust setae (evenly spaced); article 2 0.3 times as long as article 1, 2.0 times as long as wide with 4 robust setae (at least, all evenly spaced around distal margin); remaining articles all rectangular, length varying; article 3 with 2 simple setae (at least). Antenna 2 article 1 with 3 simple setae; article 2 1.1 times as long article 1, distolateral angle with 2 spines, one smaller than other, both with terminal robust seta, distoinferior margin with 1 robust and 2 simple setae; article 3 0.9 times as long as article 1, distolateral angle with spine terminated with 1 robust seta, distoinferior margin with 5 long robust and 2 short robust setae in a clump; article 4 small, 0.3 times as long article 1, with no ornamentation.

Pereopod 1 basis 6.3 times as long as wide, inferior margin with 5 setae (all SS); ischium length 4.7 times as long as wide, inferior margin with 1 seta (SS), superior margin with 2 setae (both SS); merus 1.2 times as long as wide, inferior margin with 2 setae (both SS), distosuperior margin with 2 setae (both SS); carpus 4.1 times as long as wide, inferior margin with 1 seta (SS proximal); propodus 7.5 times as long as wide, inferior margin with 5 setae (all SS); dactylus 2.3 times as long as proximal width.

Pleon 0.9 times as long as proximal width, lateral sides rounded and posterior end coming to a rounded point, with scattered simple setae. Operculum 4.0 times as long as proximal width, medial keel with proximal facing robust setae and surface, and lateral and distal margins with few scattered long setae (unable to determine actual type).

Remarks: N. quadrispinosa can be distinguished by the distinctive setation on the antennae, four spines on the anterior margin of pereonites 1–3 and 5 in conjunction with pereonite 4 where the spines are set back from the absolute margin. For further morphological discussion please read the previous remarks section for N. spicata .

Distribution: Antarctica, reliably known from the Crozet Islands to the Leopold and Astrid Coast, from 168–245 metres.

Figures

FIGURE 2. Notopais quadrispinosa (Beddard, 1886). Female lectotype, 6.0 mm. A, dorsal view; B, lateral view; C, left antenna 1 and 2, dorsal view; D, left antenna 2, ventral view; E, right antenna 1 and 2; F, left pereopod 1; G, operculum.