Dulichiopsis barnardi Laubitz 1977

Dulichiopsis barnardi Laubitz, 1977 (Figs 11–13)

[Japanese name: Shakutoridoronomi-modoki, new]

Dulichia remis: Barnard 1964: 332, fig. 12m–u. (non Dulichia remis Barnard, 1964)

Dulichiopsis barnardi Laubitz, 1977: 955, fig. 7.

Material examined. Male (OMNH-Ar-10823), 8.5 mm, off Namie Town, Fukushima Prefecture, 37°28′38"N, 141°58′38"E (KS14-6, No. 4; Fig. 1B), 531–540 m depth, using beam trawl, 2 May 2014, coll. T. Takano.

Diagnosis. Eyes composed of many dispersed ommatidia. Maxilla 1 outer plate bearing 9 terminal robust setae. Maxilla 2 inner plate with mediofacial row of setae subdistally. Male gnathopod 2, basis widened distally, propodus massive, ovoid, posterior margin weakly setose, with large proximal projection and small distal projection. Pereopod 4 basis slender. Pereopod 5 elongate, prehensile. Urosomite 1 about 1.6 times as long as pleonites 2+3. Uropod 2 outer ramus about half length of inner ramus.

Description of male [based on male (OMNH-Ar-10823), 8.5 mm]. Body (Fig. 11), dorsal margins of pereonites and pleonites slightly corrugated, urosomite 1 about 1.6 times as long as pleonites 2+3. Eyes round, large, about one third length of head, composed of many dispersed ommatidia.

Antenna 1 (Fig. 12A), peduncular article 1 with single ventral robust seta; peduncular articles 2, 3, accessory flagellum and primary flagellum lost. Antenna 2 (Fig. 12B), peduncular article 3 short; peduncular articles 4, 5 and flagellum lost. Upper lip (Fig. 12C), ventral margin with sparse short setae. Mandibles (Fig. 12D, D 1, E, E1) with length ratio of palp articles 1–3 1.0: 2.6: 1.6, articles 2 and 3 with 12 and 9–10 setae, respectively; incisor with 6 cusps, lacinia mobilis with 4 and 5 cusps in left and right, respectively, 3 and 4 accessory blades present in left and right, respectively; molar with spatula-like process in right. Lower lip (Fig. 12 F), outer and inner lobes covered with thin setae apically. Maxilla 1 (Fig. 12G, G 1, G 2), inner plate round, palp article 2 bearing 7 robust setae apically. Maxilla 2 (Fig. 12H), inner plate with distal setae and many subdistal mediofacial setae, outer plate bearing many setae on distal margin. Maxilliped (Fig. 12I), inner plate with 3 apical and 1 mediodistal short robust setae on ventral surface; outer plate bearing 10 slender robust setae mediodistally.

Gnathopod 1 (Fig. 13A) slender; coxa subrectangular; merus setose posterodistally and mediodistally; carpus long, with many setae on posterior margin and several setae on medioproximal surface; propodus densely setose posteriorly and mediodistally; dactylus long, slender, curved posteriorly, posterior margin lined with minute setae. Gnathopod 2 (Fig. 13B, B 1), coxa subtrapezoidal, gill slender; basis widened distally, curved anteriorly, anterodistal corner slightly lobate, lateral surface with several sensory setae; carpus subtriangular, weakly setose; propodus massive, ovoid, about 1.5 times as long as head, about 1.55 times length of carpus, posterior margin weakly setose, with large proximally-oriented proximal projection at about 100° angle to palm and small distal projection at about 35° angle to palm; dactylus stout, posterior margin with small quadrate projection proximally.

Pereopod 3 (Fig. 13C), coxa triangular, gill long; other parts lost. Pereopod 4 (Fig. 13D) slender; coxa triangular, gill long; basis slender, about 4.45 times as long as width, with glands in anterior and posterior parts; merus long. Pereopod 5 (Fig. 13E, E 1) about 2.0 times length of pereopod 4; coxa bearing short setae, gill short; basis and merus very long, carpus about 1.2 times as long as propodus; lateral surfaces of basis, merus and carpus with many small robust setae; propodus with palm, anterior margin lined with robust setae. Pereopods 6, 7 (Fig. 13F) lost except for coxae.

Pleopods (Fig. 13 G–I), peduncles progressively longer, each with 2 slender coupling hooks; outer rami slightly longer than inner rami, outer rami with 16, 16, 15 articles and inner rami with 15, 15, 13 articles respectively. Uropod 1 (Fig. 13J), peduncle with 10 lateral and 5 medial robust setae; outer ramus about 0.7 times as long as inner ramus, outer ramus with 14 lateral and 4 medial robust setae, inner ramus bearing 13 lateral, 15 medial and 2 distal robust setae. Uropod 2 (Fig. 13J) about 0.7 times length of uropod 1; peduncle with 2 lateral and 4 medial robust setae; outer ramus about half length of inner ramus, outer ramus with 3 lateral and 2 medial robust setae, inner ramus bearing 4 lateral and 7 medial robust setae. Telson (Fig. 13J) with 4 setae dorsally.

Coloration in life. Unknown.

Remarks. Laubitz (1977) described this species based on the female specimens. The present male specimen, however, can be identified as Dulichiopsis barnardi, because (1) the eyes are composed of many dispersed ommatidia, (2) the maxilla 2 inner plate has mediofacial setae subdistally, (3) the urosomite 1 is much longer than the pleonites 2+3, and (4) the uropod 2 outer ramus is about half length of the inner ramus.

Habitat. Bottom sediment unknown, 531–540 m depth (present study); 882 m depth (Laubitz 1977).

Distribution. Japan: off Namie Town, Fukushima Prefecture (present study). USA: off the Near Islands in the Aleutian Islands, Alaska (Laubitz 1977).