Rhachotropis clarionclippertoni Lörz, Engel, Jereczek, Ćwierz & Jażdżewska, 2026, sp. nov.

Rhachotropis clarionclippertoni sp. nov. Figs 17, 18, 19, 20 Type material. Holotype: Pacific • female, 8 mm, SMF 62817, COI: PQ 734529, body remnants and two slides with appendages, Clarion-Clipperton Zone, OMS exploration contract area, R / V Thompson, ABYSSLINE- 2, EBS, AB 2 - EB 11, 14/03/2015, 12°2.28'N, 117°14.22'W, 4097 m. Paratype: Pacific • female, 8.5 mm, SMF 62818, COI: PQ 734352, Clarion-Clipperton Zone, BGR exploration contract area, R / V Kilo Moana, MANGAN 2016, EBS, Ma 16-91, 09/05/2016, 11°49.792'N, 117°30.458'W – 11°49.842'N, 117°29.208'W, 4344– 4344 m. Additional material. Pacific • Clarion-Clipperton Zone; BGR exploration contract area, several stations (Table 2). Type locality. Abyssal Pacific Ocean, Clarion-Clipperton Zone, 12°2.28'N, 117°14.22'W, 4097 m. Description. Based on holotype, female, 8 mm, SMF 62817. Body (Figs 17, 18): all pereonites smooth; pleonites 1 and 2 smooth, pleonite 3 with a minute dorsal spine. Head (Fig. 18): dorsally smooth, no eyes visible, rostrum short, slightly downcurved. Antenna 1 (Fig. 18): peduncle article 2 narrower and longer than article 1,> 2 × as long as article 3; flagellum eight-articulated; accessory flagellum uni-articulated. Antenna 2 (Fig. 18): peduncle articles 4 and 5 equal in length; flagellum broken off. Upper lip (Fig. 19): circular in shape, ventral margins rounded, lateral margins finely setose. Mandible (Fig. 19): incisor process strongly dentate, well-developed; left lacinia mobilis denticulate; molar process conical, edge with row of strong spines; article 3 longer than article 2, articles 2 and 3 inner margin with long slender setae, plumose setae at apical tip of palp. Lower lip (Fig. 19): setose anterodistally, outer lobes separated by broad gap. Maxilla 1 (Fig. 19): inner plate bearing two subterminal plumose setae; outer plate with nine denticulate spines; article 1 of palp 1 / 3 length of second article, article 2 of palp with several slender setae. Maxilla 2 (Fig. 19): inner and outer plates subequal in length, margins bearing stout and slender setae; inner plate slightly wider than outer plate. Maxilliped (Fig. 19): inner plate distally with three strong spines; outer plate 2 × as long as inner plate, reaching almost 1 / 2 of article 2 of maxillipedal palp, outer plate margins and palp article setose. Pereon: Gnathopod 1 (Fig. 18): coxa 1 anteriorly extended; gnathopods similar in shape, subchelate; gnathopod 1 slightly smaller than gnathopod 2; basis bearing small spines at posteroventral corner; ischium and merus with long setae at posteroventral corner; carpal lobe extending width of propodus, spines at distal end of lobe and along posterior margin; propodus widened, oval; dactylus slender, reaching end of palm. Gnathopod 2 (Fig. 18): coxa 2 subquadrate; gnathopod 2 basis 1.2 × as wide as basis of gnathopod 1; ischium to dactylus similar to gnathopod 1, except carpal lobe longer and narrower. Pereopods 3 and 4 (Fig. 20): coxae 3 and 4 subquadrate. Pereopod 3 articles long and narrow; carpus, propodus and dactylus in ratio of 1: 0.6: 0.96. Pereopod 4 similar to pereopod 3, carpus, propodus and dactylus broken off. Pereopod 5 (Fig. 20): coxa 5 lobate; basis subrectangular; remaining pereopod missing. Pereopod 6 (Fig. 20): coxa 6 lobate; basis subrectangular with small posteroventral lobe; merus longer than basis; remaining pereopod missing. Pereopod 7 (Fig. 20): pereopod 7 longer than pereopods 5 and 6; basis slightly expanded, subovate; merus longer than basis; rest of pereopod missing. Pleon: Epimera 1–3 (Figs 17, 18): epimeral plates ventrally rounded; epimeral plate 3 posterior margin and posteroventral corner minutely serrated. Pleopods (Fig. 20): pleopod 2 (right side) rami with 12 and 15 articles; rami similar length, as long as peduncle. Urosome: Urosomites 1–3 (Figs 17, 18): urosome segment 1 dorsolaterally with a small spine, urosomites 2 and 3 smooth. Uropod 1 (Fig. 20): lanceolate; outer and inner ramus same length; rami shorter than peduncle. Uropod 2 (Fig. 20): lanceolate; outer ramus shorter than inner ramus; peduncle shorter than outer ramus and longer than inner ramus. Uropod 3 (Fig. 20): lanceolate; outer and inner ramus same length, nearly 2 × as long as peduncle. Telson (Fig. 18): Telson> 3 × as long as wide, with V-shaped cleft of ~ 15 %. Remarks. The combination of the following characters found in Rhachotropis clarionclippertoni sp. nov. (produced first coxa, cleft telson, rostrum shorter than 1 / 2 of first peduncle of antenna 1) is shared with the following species: R. americana Bousfield & Hendrycks, 1995, R. antarctica K. H. Barnard, 1932, R. gubilata J. L. Barnard, 1964, R. palporum Stebbing, 1908, R. portoricana J. L. Barnard, 1964, and R. rossi Lörz, 2010, but only the new species and R. portoricana have no lateral teeth on pleonites 1–3. Rhachotropis clarionclippertoni sp. nov. is very similar to R. portoricana but can be distinguished by the following characters (characters of R. portoricana in parentheses): rounded ventrolateral margin of urosomite 1 (vs ventrolateral margin shows a drawn out process), rostrum reaching only 1 / 3 of the length of the cephalic lobe (vs rostrum reaching 1 / 2 length of the cephalic lobe), length to width ratio of basis of pereopod 6 is 0.4 (vs 0.6), length to width ratio of basis of pereopod 7 is 0.54 (vs 0.65), no posterodistal lobe on basis of pereopod 7 (vs small but distinct lobe), telson cleft 15 % (vs telson cleft 8 %). Etymology. The name clarionclippertoni refers to the Clarion-Clipperton Zone in the abyssal east Pacific, a marine area known for the high density of manganese nodules, amongst which this new amphipod was collected. Distribution. Abyssal Pacific Ocean, Clarion-Clipperton Zone in 4097–4430 m depth. Molecular identification. Following the definition given by Pleijel et al. (2008), the sequence of the holotype male of Rhachotropis clarionclippertoni (SMF 62817, GenBank accession number PQ 734529) is designed as a hologenophore of all obtained sequences. The sequences of the paratype and additional individuals of the species are also available in GenBank (Table 2). Furthermore, the species has received a Barcode Index Number from Barcode of Life Data Systems: BOLD: AEB 0147 (https://doi.org/10.5883/BOLD:AEB0147).