Lepechinella macrospinosa Kodama, Mukaida, Hosoki & Jimi, 2025, sp. nov.

Lepechinella macrospinosa sp. nov. [New Japanese name: Toge-naga-gaikotsu-yokoebi] (Figs 2–8) Material examined. Holotype: NSMT-Cr 32795, 1 mature female, 11.3 mm, off Yakushima Island, Ryukyu Trench area, 29°35.3636N 130°40.8119E, 1,178m deep, on 28 Dec 2022, R/V Kaimei, beam trawl. Paratypes: all the paratypes were collected together with the holotype; NSMT-Cr 32796, 1 mature female, 9.5 mm, INSDC LC860266 (COI, 658 bp); NSMT-Cr 32797, 1 immature female, 7.6 mm, INSDC LC860267 (COI, 630 bp); NSMT-Cr 32798, 1 immature female, damaged (head lost), body length unknown, INSDC LC860268 (COI, 565 bp); NSMT-Cr 32799, sex unknown, 6.2 mm. Description. Based on holotype female (NSMT-Cr 32795, 11.3 mm), except for antennae 1, 2, and basis-dactylus of pereopod 7, which are damaged in holotype and the descriptions are based on paratype female (NSMTCr 32796, 9.5 mm). Body (Fig. 2A) laterally compressed, generally covered with sparse slender setae, often with small robust setae. HEAD (Fig. 2B–F). Rostrum (Fig. 2F) almost straight, producing anterodorsally, reaching proximal 30% of antenna 1 peduncular article 1; first cephalic tooth produced anteriorly from slightly ventral to the base of antenna 1, about 0.5 times as long as rostrum; second cephalic tooth produced anteriorly from slightly dorsal to the base of antenna 2, about 0.3 times as long as rostrum. Eyes absent, at least cannot be observed under stereomicroscope or light microscope after two-month ethanol preservation. Antenna 1 damaged in holotype. Antenna 1 in paratype female (Fig. 2B; NSMT-Cr 32796, 9.5 mm), length ratio of peduncular article 1–3 about 2: 5: 1.2, each article setose, but without robust setae; accessory flagellum (Fig. 2C) consisting of 1 article, reaching about half of flagellar article 1, subdistally with 2 slender setae; flagellum longer than peduncle, several distal articles (Fig. 2D) each with tiny sensory structure (possibly a kind of calceoli?). Antenna 2 damaged in holotype. Antenna 2 in paratype female (Fig. 2E; NSMT-Cr 32796, 9.5 mm) longer than antenna 1, each article setose, but without robust setae, peduncular article 5 about 1.1 times as long as article 4; flagellum shorter than peduncle. Mouth parts. Upper lip (Fig. 3A), distal margin setose, separated by small incision, both lobes not produced. Lower lip (Fig. 3B), damaged in holotype, distally setulose, mandibular process developed. Mandible (Fig. 3C, D), left and right incisors 3 and 3-dentate, respectively; left and right lacinia mobilis 5 and 2-dentate, respectively; accessory setal row present; molar well developed; palp with 3 articles, length ratio of articles 1–3 about 2: 6: 3, article 1 bare, article 2 with two pairs of slender setae, article 3 with two distal slender setae. Maxilla 1 (Fig. 3E), inner plate setulose, distally tapering with 3 plumose setae; outer plate setulose, lateral margin with 2 short setae near basal area of palp, distal margin obliquely truncate, with 9 dentate robust setae; palp with two article, article 1 short, bare, article 2 slightly expanded distally, lateral to distal margin rounded, medial margin slightly concave, distal to distomedial margin with 8 robust setae, ventral surface with 2 subdistal slender setae. Maxilla 2 (Fig. 3F), inner plate setulose, slightly inward curved, distally rounded with group of long slender setae and thick plumose seta, medial margin with row of fine setae; outer plate slightly longer than inner plate, distally broadened, distally rounded with row of slender setae. Maxilliped (Fig. 3G), inner plate, lateral margin roundly convex, medial margin straight, distal margin slightly oblique with 3 stubby setae, dorsal surface setulose, with 2 thick plumose setae and several slender setae; outer plate subrectangular, lateral margin convex, medial to distal margin with 10 robust setae, the robust setae on proximal side shorter and thicker, the robust setae on distal side thinner and longer, distalmost robust setae damaged in holotype, ventromedial margin with submarginal row of slender setae, dorsal surface setulose; palp elongate with 4 articles, length ratio of articles 1–4 about 2: 6: 2.5: 1 (unguis on article 4 ignored), article 1 with 2 slender setae on distomedial corner, article 2 elongate, reaching beyond distal end of outer plate, with row of long slender setae on medial margin and ventral surface, respectively, article 3 densely setose on distal half, article 4 short, with several short slender setae on distomedial corner, with strong terminal unguis, terminal unguis about 1.5 times as long as article 4. PEREON. Pereonite 1 (Fig. 2A) with two dorsal teeth, anterior tooth curved anteriorly, posterior tooth produced dorsally, almost straight; pereonites 2–6, each with dorsal tooth, each tooth almost straight, produced dorsally; pereonite 7 with larger tooth than that on pereonites 2–6, tooth produced and curved posteriorly. Gnathopod 1 (Fig. 4A, B) subchelate, slender, long; coxa deeper than wide, curved and produced anteriorly, distally tapering, not bifid, anterior margin concave, posteroventral margin rounded, both anterior and posterior margin with slender setae, ventral margin with small indistinct teeth on basal area of each setae; basis slender, elongate, slightly curved anteriorly, anterior margin slightly concave with row of long slender setae, posterior margin slightly convex with dense long slender setae; posterodistal corner with group of slender setae; ischium bare anteriorly, posterodistal corner with group of slender setae; merus short, bare anteriorly, posterior margin with sparse slender setae, distal margin oblique; carpus elongate, about 0.7 times as long as basis, anterior margin with dense groups of long slender setae in distal 70%, posterior margin and posteromedial surface covered with dense groups of long slender setae; propodus about 0.7 times as long as carpus, anterior margin straight to slightly convex with anterolateral and anteroventral slender setae, posterior margin roundly convex with several long robust setae, long and short slender setae, palm indistinct, medial surface with several lender setae, anterodistal corner with group of slender setae; dactylus about 0.7 times as long as propodus, tapering, curved, with anteroproximal small setae, anterior and posterior margin without teeth. Gnathopod 2 (Fig. 4C, D) subchelate, slender; coxa deeper than wide, anterior margin convex with several short slender setae, anteroventral corner pointed, posteroproximal margin straight, posterior to central margin with slender setae, with pointed tooth; basis-dactylus larger than gnathopod 1; basis slender, elongate, slightly curved anteriorly, anterior margin slightly concave with row of long slender setae, posterior margin slightly convex with dense long slender setae; posterodistal corner with group of slender setae; ischium bare anteriorly, posterodistal corner with group of slender setae; merus sub-triangular, bare anteriorly, with sparse slender setae on posterior margin, distal margin oblique; carpus elongate, longer gnathopod 1 carpus, about 0.8 times as long as gnathopod 2 basis, rectilinear, anterior and posterior margins with groups of long setae, distal margin triangularly projected slightly overlapping proximal part of propodus; propodus about 0.5 times as long as carpus, anterior margin straight to slightly convex with anterolateral and anteroventral slender setae, posterior margin roundly convex with several long robust setae, long and short slender setae, palm indistinct, medial surface with several groups of slender setae, anterodistal corner with group of slender setae; dactylus about 0.7 times as long as propodus, tapering, curved, with anteroproximal small setae, anterior and posterior margin without teeth. Pereopod 3 (Fig. 5A) elongate, slender; coxa setose, anterior margin convex, ventral margin concave, posterior margin straight, anteroventral angle slightly produced ventrally, posteroventral corner rounded; basis rectilinear, anterior margin with row of robust setae, posterior margin with long setae and robust setae; ischium short, anteriorly bare, posterodistal corner with group of setae; merus-propodus, each segment rectilinear, anterior and posterior margins with robust setae, thick setae and slender setae; merus subequal or slightly shorter than basis, broader than carpus, anterodistal corner slightly produced distally; carpus about 0.7 times as long as merus, slightly broader than propodus; propodus with subequal length to carpus; dactylus elongate, about 1.3 times as long as propodus, tapering, curved, with subdistal short slender setae, dactylus slightly narrowed around distal area of the short setae. Pereopod 4 (Fig. 5B) similar to pereopod 3 in shape, but slightly shorter than pereopod 3, posteroventral corner of coxa not produced like in pereopod 3 coxa, dactylus longer than pereopod 3 dactylus. Pereopod 5 (Fig. 6A) coxa bilobate, anteroventral area produced ventrally into a pointed anterior lobe, baring short setae, posterior robe round, not produced, beringed long slender setae; basis, anterior margin rounded with several long slender setae in proximal 20%, straight in distal 80%, anterior and posterior margin with sparse robust setae, posteroproximal area with small brunt projection; merus-propodus, each segment rectilinear, anterior and posterior margins with sparse robust setae and slender setae; merus about 0.7 times as long as basis; carpus about 1.4 times as long as merus; propodus about 0.7 times as long as carpus; dactylus elongate about 1.4 times as long as propodus, curved, tapering, with subdistal short slender setae, anterior and posterior margins slightly narrowed around distal area of the short setae. Pereopod 6 (Fig. 6B); coxa wider than deep, indistinctively bilobate, anterior lobe unproduced, deeper than wide with several short setae, posterior lobe rounded, wider then deep, slightly produced posteroventrally, with long slender setae; basis-da