An enigmatic Rhachotropis (Crustacea: Amphipoda: Eusiridae) from New Zealand Author Lörz, Anne-Nina text Zootaxa 2015 4006 2 383 391 journal article 10.11646/zootaxa.4006.2.9 2a896a0e-063f-4d25-9207-4307112c7b1d 1175-5326 242156 8BEEC901-E38A-4B18-BBAA-683FFF090233 Rhachotropis oweni sp. nov. ( Figs 2–6 ) Material examined . Holotype : NIWA 82905, female, 13.6 mm , Clark Seamount, Southern Kermadec Ridge, New Zealand , 36°26'43.08'' S , 177°50'21.12''E , epibenthic sledge, TAN1206/99, 850– 927 m , 24 April 2012 . Paratype : NIWA 78497, 17.4 mm , Chatham Rise, New Zealand , 44°46'39.60''S , 174°07'58.80''E , beam trawl, 821–822 m ,TAN1116/58, 0 9 November 2011 . Etymology. Rhachotropis oweni sp. nov. is named after Owen Anderson, acknowledging his contribution and dedication to New Zealand’s deep-sea fauna. Diagnosis. Body delicate, ornamented. Rostrum short. Eyes present, bulging laterally. Humps on head and pereonites. Pereonite 7 nearly as long as body. Pleonite 1 bearing dorsolateral pointed processes, dorsally smooth. Pleonite 2 and 3 bearing dorsolateral pointed processes, and short pointed middorsal process. Telson cleft 10 %, triangular, long and narrow. Description. Antenna 1 and 2 equal in length. Antenna 1 article 2 slightly shorter than article 1, 2.5 times as long as article 3; flagellum 10-articulate. Antenna 2 peduncle article 4 and 5 subequal in length, several plumose setae on third article; flagellum 15-articulate. Mandible with incisor process well developed; lacinia mobilis denticulate; molar process conical; palp article 1 short, about one-third length of article 2, articles 2 and 3 with long slender setae, article 3 nearly as long as article 2. Maxilla 1 inner plate bearing 2 subterminal plumose seta; outer plate with 9 denticulate spines; article 1 of palp with long setae at outer margin, palp article 2 with several slender setae at tip. Maxilla 2 inner and outer plate subequal in length, margins bearing stout and slender setae; inner plate slightly wider than outer plate. Maxilliped outer plate 2.5 times as long as inner plate, reaching half of article 2 of maxillipedal palp. Hypopharynx setose, outer lobes separated by broad gap. Gnathopods similar in shape, subchelate. Gnathopod 1 slightly smaller than gnathopod 2. Gnathopod 1 coxa 1– 4 subquadrate. Gnathopod 1 basis bearing several small spines at anteroventral corner; ischium and merus long setae at posteroventral corner; carpus lobe extending width of propodus, spines at terminal end of lobe; propodus broad, oval; dactylus slender, reaching end of palm. Pereopods 3 and 4 articles long and narrow; carpus, propodus and dactylus similar in length. Pereopod 5 basis with acute posterior margin; pereopod 6 basis similar triangular shape. Pereopod 5 and 6 long, merus slightly inflated. Pereopod 7 longer than pereopod 5 and 6; basis with large rounded extension posteriorly; merus posteroventral angle produced; propodus same length as carpus. Pleopod 2 (right side) rami with 16 and 21 articles, respectively; rami 1.5 times as long as peduncle. Uropod 1 rami shorter than peduncle, outer rami slightly shorter than inner rami. Uropod 2 rami same length; peduncle shorter than ramus. Uropod 3 rami longer than peduncle, inner rami slightly longer than outer rami. Telson more than three times as long as wide, cleft 10%. FIGURE 1. Sampling locations of Rhachotropis oweni sp. nov. on the Kermadec Ridge (holotype) and the Chatham Rise, each below 800 m depth. FIGURE 2. Rhachotropis oweni sp. nov. , holotype, 13.6 mm, female, NIWA 82905: a) habitus lateral; b) maxilliped; c) antenna 1; d) antenna 2; e) maxilla 1. Scale bars: a = 1 mm; b–d = 0.5 mm; e = 0.1 mm. FIGURE 3. Rhachotropis oweni sp. nov. , holotype, 13.6 mm, female, NIWA 82905: a) hypopharynx; b) maxilla 2; c) left mandible; d) right mandible. Scale bars = 0.1 mm. Colour. Eyes cream/white; body light orange; gnathopods dark red. Distribution. New Zealand , Kermadec Ridge and Chatham Rise, 821– 927 m . Remarks. Rhachotropis oweni sp. nov. from New Zealand differs from all other 60 Rhachotropis species by the combination of following characters: long dorsolateral projections on pereonites 1–3; pereonite 1 dorsally smooth; eyes present; mid-dorsal protuberances on head and pleonites; unproduced coxa 1, pleopod 5 and 6 basis triangular, pereopod 7 basis with large rounded extension.