Rhachotropis oweni, Lörz, Anne-Nina, 2015

Lörz, Anne-Nina, 2015, An enigmatic Rhachotropis (Crustacea: Amphipoda: Eusiridae) from New Zealand, Zootaxa 4006 (2), pp. 383-391 : 384-387

publication ID	https://doi.org/ 10.11646/zootaxa.4006.2.9
publication LSID	lsid:zoobank.org:pub:8BEEC901-E38A-4B18-BBAA-683FFF090233
DOI	https://doi.org/10.5281/zenodo.6113519
persistent identifier	https://treatment.plazi.org/id/BE0CE2C9-8DE6-4C1E-AA75-C1E35A2F7843
taxon LSID	lsid:zoobank.org:act:BE0CE2C9-8DE6-4C1E-AA75-C1E35A2F7843
treatment provided by	Plazi
scientific name	Rhachotropis oweni
status	sp. nov.

Treatment

Rhachotropis oweni View in CoL sp. nov.

( Figs 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 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%.

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.