Notopais beddardi, 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 : 10-13

Notopais beddardi n. sp. ( Fig. 3 )

Material examined.— Holotype. Female (4.0 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 2004.677).

Description: Holotype. Body 2.4 times as long as greatest width (from spine to spine) of pereonite 2; widest at pereonite 4; cuticle not highly calcified, lightly setose. Cephalon lightly setose with 2 dorsal spines; posterior margins rounded, but almost square; ridge encompassing antennae with no extension. Pereonites 1–4 anterior margins each with 4 well developed spines; pereonite 5 anterior margin with evenly spaced stiff simple setae; pereonite 5 with anterolateral margin rounded; pereonites 1–4 anterolateral margins with spines, 5–7 rounded and smooth; pereonites 1–4 each with pair of lateral, sub­marginal spines.

Antenna 1 article 1 rectangular and elongate, 1.7 times as long as wide, dorsal surface concave and forms shallow depression, distal margin with 5 robust setae; article 2 elongate, 0.4 times as long as article 1, 2.4 times as long as wide, with 2 robust setae (distal). Antenna 2 articles 1–3 more or less triangular; article 1 spine on distolateral angle with 3 additional robust setae on ventral side; article 2 inferior margin 1.2 times as long as article 1, distolateral angle with spine and 4 terminal robust setae, distoinferior margin with 2 robust setae; article 3 inferior margin 1.3 times as long as article 1, with 5 long robust and 3 short robust setae on distosuperior rim of article, distoinferior margin with 1 robust seta; article 4 small, 0.6 times as long as article 1, with no ornamentation.

Pereopod 2 basis 2.7 times as long as wide, inferior margin with 6 setae (all SS); ischium 2.1 times as long as wide, inferior margin with 7 setae (1 SS, 6 sub­marginal SS), lateral face with 3 setae (all SS), superior margin with 2 setae (both SS, in distal half); merus 1.7 times as long as wide, inferior margin with 4 setae (all SS), distosuperior margin with 4 setae (all SS); carpus 6.0 times as long as wide, inferior margin with 13 setae (all RS, evenly spaced), superior margin with 4 setae (all SS, in distal half); propodus 8.2 times as long as wide, inferior margin with 6 setae (all SS), superior margin with 3 setae (all SS, distal half); dactylus 9.7 times as long as proximal width.

Pleon 0.6 times as long as proximal width, lateral sides rounded and posterior end coming to a rounded point, with scattered simple setae. Operculum 1.9 times as long as proximal width, medial keel with evenly spaced downward facing robust setae, lateral margins and distal surface with few setae (unable to determine actual types).

Remarks: Notopais beddardi n. sp. can be identified by the combination of having only two dorsal spines on the cephalon; anterior facing marginal spines on only the first four pereonites, with robust setae on the corresponding margin of the fifth; the unique setal combinations of the first two articles in antenna 1 and the first three articles in antenna 2; the rounded anterior margin of pereonite 5; and the anterolateral margins of pereonites 5 and 6 rounded and smooth, and not coming to a point. The spines on the anterior margin of article 4 on N. beddardi are set on the absolute anterior margin, similar to that seen in N. spicata (although they are not as pronounced or as acutely angled) instead of almost being dorsal as is in N. quadrispinosa . N. beddardi does not have anterior spines on the fifth pereonite as in N. quadrispinosa , instead it has a row of short stout setae. The shape of pereonites 5–7 also differs between the two species. In N. beddardi these pereonites are broader than those in N. quadrispinosa . Pereonite 5 in N. beddardi has a rounded anterolateral margin, and the corresponding margins of pereonites 6 and 7 are not as acute as those in N. quadrispinosa . The spination of both antennae are also different between the two species. The first article of antenna 1 in N. beddardi has long robust setae around the distal margin, while N. quadrispinosa has robust setae along the superior margin. The number of robust setae on the spines of the first two antennal articles of antenna 2 also differ, with N. beddardi having many more robust setae on the distosuperior margins than in N. quadrispinosa which has a single robust seta terminating each spine. The position of robust setae on the distal margin of the article 3 of antenna 2 also differs between the two species, with those of N. beddardi being on the superior margin, while on N. quadrispinosa they are on the inferior margin.

Distribution: Known only from type locality, off Kerguelen Island, southern Indian Ocean.

Etymology: For Frank E. Beddard, the distinguished biologist, who described the many isopods which were collected during the Challenger expedition of 1873–1876.

Figures

FIGURE 3. Notopais beddardi n. sp. Female holotype, 4.0 mm. A, dorsal view; B, lateral view; C, left antenna 1 and 2, dorsal view; D, left antenna 2, ventral view; E, right pereopod 2; F, operculum.