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Bibliográfalaš dieđut
Váldodahkkit: Lörz, Anne-Nina, Engel, Laura, Jereczek, Halina, Ćwierz, Nikodem, Jażdżewska, Anna M.
Materiálatiipa: Recurso digital
Giella:
Almmustuhtton: Zenodo 2026
Fáttát:
Liŋkkat:https://doi.org/10.5281/zenodo.19202735
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  • <p><i>Rhachotropis clarionclippertoni</i> sp. nov.</p><p>Figs 17, 18, 19, 20</p><p><b>Type material.</b></p><p><i>Holotype</i>: 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 <i>Thompson</i>, ABYSSLINE- 2, EBS, AB 2 - EB 11, 14/03/2015, 12°2.28'N, 117°14.22'W, 4097 m. <i>Paratype</i>: Pacific • female, 8.5 mm, SMF 62818, COI: PQ 734352, Clarion-Clipperton Zone, BGR exploration contract area, R / V <i>Kilo Moana</i>, 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.</p><p><b>Additional material.</b></p><p>Pacific • Clarion-Clipperton Zone; BGR exploration contract area, several stations (Table 2).</p><p><b>Type locality.</b></p><p>Abyssal Pacific Ocean, Clarion-Clipperton Zone, 12°2.28'N, 117°14.22'W, 4097 m.</p><p><b>Description.</b></p><p>Based on holotype, female, 8 mm, SMF 62817.</p><p><i>Body</i> (Figs 17, 18): all pereonites smooth; pleonites 1 and 2 smooth, pleonite 3 with a minute dorsal spine.</p><p><i>Head</i> (Fig. 18): dorsally smooth, no eyes visible, rostrum short, slightly downcurved.</p><p><i>Antenna 1</i> (Fig. 18): peduncle article 2 narrower and longer than article 1,> 2 × as long as article 3; flagellum eight-articulated; accessory flagellum uni-articulated.</p><p><i>Antenna 2</i> (Fig. 18): peduncle articles 4 and 5 equal in length; flagellum broken off.</p><p><i>Upper lip</i> (Fig. 19): circular in shape, ventral margins rounded, lateral margins finely setose.</p><p><i>Mandible</i> (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.</p><p><i>Lower lip</i> (Fig. 19): setose anterodistally, outer lobes separated by broad gap.</p><p><i>Maxilla 1</i> (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.</p><p><i>Maxilla 2</i> (Fig. 19): inner and outer plates subequal in length, margins bearing stout and slender setae; inner plate slightly wider than outer plate.</p><p><i>Maxilliped</i> (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.</p><p><b>Pereon: <i>Gnathopod 1</i></b> (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.</p><p><i>Gnathopod 2</i> (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.</p><p><i>Pereopods 3 and 4</i> (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.</p><p><i>Pereopod 5</i> (Fig. 20): coxa 5 lobate; basis subrectangular; remaining pereopod missing.</p><p><i>Pereopod 6</i> (Fig. 20): coxa 6 lobate; basis subrectangular with small posteroventral lobe; merus longer than basis; remaining pereopod missing.</p><p><i>Pereopod 7</i> (Fig. 20): pereopod 7 longer than pereopods 5 and 6; basis slightly expanded, subovate; merus longer than basis; rest of pereopod missing.</p><p><b>Pleon: <i>Epimera 1–3</i></b> (Figs 17, 18): epimeral plates ventrally rounded; epimeral plate 3 posterior margin and posteroventral corner minutely serrated.</p><p><i>Pleopods</i> (Fig. 20): pleopod 2 (right side) rami with 12 and 15 articles; rami similar length, as long as peduncle.</p><p><b>Urosome: <i>Urosomites 1–3</i></b> (Figs 17, 18): urosome segment 1 dorsolaterally with a small spine, urosomites 2 and 3 smooth.</p><p><i>Uropod 1</i> (Fig. 20): lanceolate; outer and inner ramus same length; rami shorter than peduncle.</p><p><i>Uropod 2</i> (Fig. 20): lanceolate; outer ramus shorter than inner ramus; peduncle shorter than outer ramus and longer than inner ramus.</p><p><i>Uropod 3</i> (Fig. 20): lanceolate; outer and inner ramus same length, nearly 2 × as long as peduncle.</p><p><i>Telson</i> (Fig. 18): Telson> 3 × as long as wide, with V-shaped cleft of ~ 15 %.</p><p><b>Remarks.</b></p><p>The combination of the following characters found in <i>Rhachotropis clarionclippertoni</i> sp. nov. (produced first coxa, cleft telson, rostrum shorter than 1 / 2 of first peduncle of antenna 1) is shared with the following species: <i>R. americana</i> Bousfield & Hendrycks, 1995, <i>R. antarctica</i> K. H. Barnard, 1932, <i>R. gubilata</i> J. L. Barnard, 1964, <i>R. palporum</i> Stebbing, 1908, <i>R. portoricana</i> J. L. Barnard, 1964, and <i>R. rossi</i> Lörz, 2010, but only the new species and <i>R. portoricana</i> have no lateral teeth on pleonites 1–3. <i>Rhachotropis clarionclippertoni</i> sp. nov. is very similar to <i>R. portoricana</i> but can be distinguished by the following characters (characters of <i>R. portoricana</i> 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 %).</p><p><b>Etymology.</b></p><p>The name <i>clarionclippertoni</i> 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.</p><p><b>Distribution.</b></p><p>Abyssal Pacific Ocean, Clarion-Clipperton Zone in 4097–4430 m depth.</p><p><b>Molecular identification.</b></p><p>Following the definition given by Pleijel et al. (2008), the sequence of the holotype male of <i>Rhachotropis clarionclippertoni</i> (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).</p>