OCTOPUPILLA FELIX TOMIKAWA SP. NOV.

Type material: Holotype: female, 7.7 mm (appendages on slide and carcass in ethanol), NSMT-Cr 16655, shallow riverbed of the Koza River (33°32′10″N, 135°47′47″E), Kozagawa Town, Wakayama Prefecture, 11.iii.2004, collected by N. Matsumoto. Paratypes: female, 5.9 mm (appendages on slide and carcass in ethanol), NSMT-Cr 16656, five females, 3.7–6.9 mm (ethanol), NSMT-Cr 16657, same data as holotype; two females, 6.4 mm, 5.5 mm (for each, appendages on slide and carcasses in ethanol), NSMT-Cr 16658– 16659, shallow riverbed of the Takatomi River, Kushimoto Town, Wakayama Prefecture, 19.vi.2003, collected by A. Ohtaka ; two females, 6.2 mm, 5.5 mm (for each, appendages on slide and carcasses in ethanol), NSMT-Cr 16660–16661, from 60 to 80 cm depth on bank of Kaifu River (33°36′50″N, 134°19′29″E), Yoshida, Kaifu Town, Tokushima Prefecture, 6.x.2002, collected by Y. Morimoto.

Etymology: The epithet of the species name is from Latin felix (happy, fortunate).

Description: Holotype, female, NSMT-Cr 16655. Head (Fig. 7B): shorter than pereonites 1 and 2 combined; inferior antennal sinus deep, with rounded angle; eyes vestigial, represented by 8 pigment spots; rostrum short; lateral cephalic lobe rounded. Antenna 1 (Fig. 7C): long, nearly as long as body length; peduncular articles 1, 2 and 3 with length ratios 1.0: 1.0: 0.4; article 1 length equal to head length, posterodistal part with robust seta; articles 2–3 with lateral and medial setae; accessory flagellum 4-articulate (Fig. 7D); primary flagellum 41-articulate, articles with distal setae, calceoli and aesthetascs lacking. Antenna 2 (Fig. 7E): about half length of antenna 1; peduncular article 3 short, not reaching middle of peduncular article 1 of antenna 1; peduncular articles 4–5 with lateral and medial setae; length of article 4 0.9 × length of article 5; flagellum 21-articulate, articles with distal setae, calceoli lacking.

Pereonites 1–7 (Fig. 7A): smooth, with fine setae. Pleonites 1–3 (Fig. 12A–C): smooth, with fine setae, each dorsal margin with 4 setae; pleonites 1–3 decreasing in length. Coxae: coxae 1–4 with many marginal and facial setae; posterior margin of coxa 4 widely excavate (Fig. 10C); anterior lobe of coxae 5–6 dominant (Fig. 11A, C); coxa 7 shallow, 0.5 × as deep as wide (Fig. 11E). Urosomites 1–2 (Fig. 12D, E): each dorsal margin with pair of clusters of robust setae. Urosomite 3 (Fig. 12F): dorsal margin with a pair of robust setae and a single robust seta.

Upper lip (Fig. 8A): ventral margin weakly rounded, with fine setae. Lower lip (Fig. 8B): outer lobes broad, setulose, shoulder round; inner lobes partly fused, indistinct. Mandible (Fig. 8C, E): left and right incisors 5- and 4-dentate, respectively (Fig. 8D, F); left lacinia mobilis 4-dentate (Fig. 8D), right lacinia bifid (Fig. 8F); molar moderately strong, triturative, with single plumose seta (left molar broken); palp 3-articulate, articles 1, 2 and 3 with length ratios 1.0: 4.0: 3.0 on left mandible, 1.0: 3.0: 2.5 on right mandible; article 1 unarmed; article 2 with 14 or 15 submarginal setae; article 3 with cluster of A-setae, many D- setae, and 4 E-setae, with setulose outer face. Maxilla 1 (Fig. 8G, H): inner plate triangular, with 14 medial plumose setae; outer plate with 11 robust serrate setae (Fig. 8K); palp 2-articulate, longer than outer plate; article 1 unarmed; article 2 of right maxilla 1 with 7 robust setae and 3 slender setae (Fig. 8I); article 2 of left maxilla 1 with 6 robust setae and slender seta (Fig. 8J). Maxilla 2 (Fig. 8L): inner plate with 13 plumose facial setae in oblique row. Maxilliped (Fig. 8M): inner plate reaching end of palp article 1, quadrate, with 3 apical, and 1 robust subapical setae, and associated setae; medial margin with row of plumose setae in distal half (Fig. 8N); outer plate narrowing distally, reaching half of palp article 2, with row of robust setae extending from apex along medial margin (Fig. 8O); palp 4-articulate; article 2 long, length 1.8 × length of article 1 and 1.3 × length of article 3; both articles medially setose; article 3 with rugose apical lobe.

Gnathopods: dissimilar in size and form. Gnathopod 1 (Fig. 9A): anterior and posterior margins of basis with long setae; ischium and merus short, ventral margin of merus setose; carpus about equal to propodus in length, not lobate, with medial setae, ventral margin lined with setae; propodus stout, palm lined with small triangular protuberances and setae, inner and outer distal corners each with 3 robust setae (Fig. 9B); dactylus thick, curved, posterior margin smooth (Fig. 9C). Gnathopod 2 (Fig. 9D): posterior margin of basis with long setae; ischium and merus more slender than those of gnathopod 1; carpus long, length 1.2 × length of propodus, not lobate, with medial setae, ventral margin lined with setae; propodus more slender than that of gnathopod 1, palm lined with small triangular protuberances and setae, inner and outer distal corners each with 3 robust setae (Fig. 9E); dactylus thick, curved, posterior margin smooth (Fig. 9F).

Pereopod 3 (Fig. 10A): slender, posterior margin of basis with long setae; ischium short, almost as long as wide; length ratios of merus, carpus and propodus = 1.0: 0.8: 0.8, with short setae marginally; dactylus length 0.3 × length of propodus, with 2 setae (Fig. 10B). Pereopod 4 (Fig. 10C): like pereopod 3, except: length ratios of merus, carpus, and propodus = 1.0: 0.9: 0.8; dactylus with three setae. Pereopod 5 (Fig. 11A): anterior margin of basis with robust setae, posterior margin with short setae, posteroventral lobe rounded; ischium short, almost as long as wide; length ratios of merus, carpus and propodus = 1.0: 1.4: 1.6; dactylus length 0.3 × length of propodus, with 2 setae (Fig. 11B). Pereopod 6 (Fig. 11C): like pereopod 5, except: ischium short, length 0.8 × width; length ratios of merus, carpus and propodus = 1.0: 1.3: 1.6; dactylus slender, length 0.3 × length of propodus, with 2 setae (Fig. 11D). Pereopod 7 (Fig. 11E): like pereopod 5, except: ischium short, length 0.7 × width; length ratios of merus, carpus and propodus = 1.0: 1.5: 1.8; dactylus stout, length 0.2 × length of propodus, with 2 setae (Fig. 11F).

Brood plates: narrow, lacking brood setae, on pereopods 2–5. Pleopods (Fig. 11G, J, K): peduncle and rami long; retinacula paired, without associated setae (Fig. 11H); inner basal margin of inner ramus of pleopods 1–3 with 3, 3, and 2 bifid setae, respectively (Fig. 11I); outer ramus 13-, inner ramus 11-articulate. Epimeral plates 1–3: not pointed posterodistally. Epimeral plate 1 (Fig. 12G): posterior margin with 2 setae. Epimeral plate 2 (Fig. 12H): posterior margin with 3 setae, ventral submargin with single robust seta. Epimeral plate 3 (Fig. 12I): posterior margin with 4 setae, ventral submargin with 2 robust setae.

Uropod 1 (Fig. 12J): length of peduncle 1.5 × length of inner ramus, with robust setae on dorsolateral and dorsomedial margins, and with 3 basofacial robust setae; length of outer ramus 0.9 × length of inner ramus, outer and inner margins with 1 and 2 robust setae, respectively; outer and inner margins of inner ramus each with 2 robust setae, ventral margin with single slender seta. Uropod 2 (Fig. 12K–M): length of peduncle 1.1 × length of inner ramus, with robust setae on dorsolateral and dorsomedial margins; length of outer ramus 0.7 × length of inner ramus, outer and inner margins each with single robust seta; outer and inner margins of inner ramus with 1 and 2 robust setae, respectively. Uropod 3 (Fig. 12N): length of peduncle 0.5 × length of inner ramus, with 3 robust setae; outer ramus 2-articulate, terminal article distinct, length 0.3 × length of proximal article (Fig. 12P); outer margin of proximal article with pair and 4 clusters of robust setae, inner margin with 5 plumose setae, single simple seta, single robust seta, and 5 pairs of robust setae; inner ramus long, length 0.7 × length of outer ramus, outer margin with 3 plumose setae, single simple seta, and 4 robust setae. Telson (Fig. 7F): length 1.1 × basal maximum width, dorsolateral margins with 3 robust setae and 2 fine setae, each lobe with 3 or 4 robust setae apically in 1 row; cleft 63%.