Leongathus alannah Taylor, 2006, sp. nov
Creators: name: Taylor, Joanne
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Phoxocephalidae
Leongathus
Leongathus alannah

description: Leongathus alannah sp. nov   
Figures 1–4  
 Material examined. Holotype: Australia, Tasman Sea, West Norfolk Ridge, Wanganella Bank (32°36.29'S, 167°43.59'E), 707 m, beam trawl, P.B. Berents, 29 May 2003 (stn TAN0308/107), AM P68013 (female, tl. 20 mm).   
Paratypes: Type locality, AM P73354 (1 female, tl. 16 mm). Australia, TasmanSea,NorthNorfolkRidge,(28°51.13'S, 167°42.32'E), 812 m, beam trawl, D.J. Bray, 15 May 2003 (stn TAN0308/029) NMV J53346 (2 females, tl. 13–14 mm). Tasman Sea, North Norfolk Ridge, (32°36.18'S, 167°47.26'E), 1029 m, beam trawl, P.B. Berents, 29 May 2003 (stn TAN0308/111), AM P66426 (female, tl. 18 mm).  
 Description. Female. Eyes present. Rostrum unconstricted, exceeding apex of peduncular article 1 on antenna 1. Antenna 1 peduncular article 1 about 1.5 times as long as wide, about 2.1 times as wide as peduncular article 2, ventral margin with 4 setae, dorsal apex with 3 setae; peduncular article 2 about 0.5 times as long as peduncular article 1, with 13 ventral and 3 apical setae; primary flagellum with 16 articles, about 0.8 times as long as peduncle; accessory flagellum with 12 articles. Antenna 2 not ensiform, peduncular article 4 with 11 robust setae in 1 apical row, dorsal margin with 2 notches each bearing 1 robust seta and simple setae, ventral margin with 19 long setae, 3 long ventrodistal robust seta; peduncular article 5 about 0.8 times as long as peduncular article 4, with 7 facial robust seta, dorsal margin with 4 setae, ventral margin with 15 long setae; flagellum 1.1 times as long as peduncular articles 4–5 combined, with 16 articles. Mandible, molar partly trituritive, bearing 13 large teeth; right incisor with 3 teeth; left incisor with 3 humps in 2 branches; right lacinia mobilis bifid, distal branch shorter than proximal, flabellate, denticulate, proximal branch simple; left lacinia mobilis with 5 teeth; right raker 10; left rakers 11; molars composed of elongate lamina in form of cone bearing 14 cusps and 2 short plusetae weakly disjunct, molars covered with fine setae; palp article 1 short, article 2 with 10 medium inner apical setae, 6 outer setae and 4 facial setae, article 3 about 1.1 times as long as article 2, apex oblique with 19 robust-slender setae, with 6 basofacial setae. Maxilla 1 inner plate bearing 2 long apical pluseta, 3 apicolateral much shorter seta; palp article 2 with 18 marginal robust setae. Maxilla 2 plates extending equally, outer slightly broader than inner, setation of inner and outer plate as illustrated. Maxilliped inner plates with 2 large thick apical robust setae, 6 apicofacial setae; outer plate large with 12 medial and apical robust setae, 13 apical and lateral setae; palp article 1 lacking apicolateral setae, article 2 with 3 apicolateral setae, medial margin of article 2 strongly setose, article 3 protuberant, with 12 facial setae, 5 lateral setae, nail of article 4 obsolescent, with 2 accessory setules. Coxa 1 slightly expanded distally; main ventral setae of coxae 1–4=21–25–18–43, posteriormost seta of coxae 1–3 shortened; anterior and posterior margins of coxa 4 divergent, posterodorsal corner rounded, posterodorsal margin short, width-length ratio of coxa 4 almost = 5:6. Long posterior setae on basis of gnathopods 1–2 and pereopods 3–4 =17–19–21–16, short posteriors = 2–0–3–2, long anteriors = 12–20–12–6, short anteriors = 1–0–2–0.   
Gnathopod 1 carpus free, gnathopod 2 enlarged, carpus cryptic. Width ratios of carpus-propodus on gnathopods 1–2 = 9:11 and 8:19, length ratios = 17:23 and 1:5; palmar humps ordinary, palms oblique. Pereopods 3–4 similar, facial setae on merus = 9 and 9, on carpus = 10 and 10; main spine of carpus extending to M. 77 and M. 95, carpus lacking proximoposterior robust setae; robust setae formula of propodus = 8+4 and 9+9; acclivity on inner margin of dactyls of pereopods 3–4 weak, obsolescent, emergent setule short, midfacial pluseta ordinary. Coxae 5–7 posteroventral setae formula = 23–13–21; merus-carpus of pereopod 5 medium of pereopod 6 narrow, facial robust setae rows sparse, facial ridge formula on basis of pereopods 5–7 = 0–1–1, anterior ridge of pereopod 7 long; width ratios of basis, merus, carpus, propodus of pereopod 5 = 2:2:2:1, of pereopod 6 = 19:10:8:4, of pereopod 7 = 35:12:11:5, length ratios of pereopod 5 = 15:6:6:8, of pereopod 6 = 18:22:19:22, of pereopod 7 = 37:14:14:5; basis of pereopod 7 barely exceeding apex of merus, with row of 9 facial setae along facial ridge, with ventral setae. Pleopods 1–3 with 2 coupling hooks; articles on outer rami = 24–22–24; articles on inner rami = 16–17–17.  
Epimeron 1 posteroventral corner rounded, anteroventral margin with 26 medium setae, posterior margin with 12 setae; epimeron 2 posteroventral corner rounded, with 3 rows of 5–7 anteroventral setae, posterior margin with 12 setae; epimeron 3 posteroventral corner rounded, ventral margin with 6 setae, posterior margin with 18 setae. Urosomite 1 naked; urosomite 3 without dorsal hook. Uropods 1–2 rami with distinct apical nails, uropod 1 outer ramus with 3 dorsal robust setae, inner without robust setae, uropod 2 outer and inner rami with 1 dorsomedial robust seta; uropod 1 peduncle with 11 apicolateral robust setae, with 3 sets of 1–3 basofacial slender setae, without apical enlarged robust seta; uropod 2 peduncle with 9 dorsal robust setae and 5 slender setae; apicolateral corners of peduncles on uropods 1–2 without comb. Uropod 3 unreduced, outer ramus longer than peduncle. Uropod 3 peduncle with 5 ventral robust setae, dorsally with 1 lateral robust seta; rami feminine, inner extending to M. 80 on article 1 of outer ramus, apex with 1 setae, medial margin with 4 slender setae, lateral margin naked, article 2 of outer ramus very short, 0.05, bearing 2 long setae, apicomedial margin of article 1 with 4 slender setae, lateral margin with 4 acclivities, robust setal formula = 1–2–2–2, slender setae formula = 1–0–0–0. Telson length-width ratio = 17:19, almost fully cleft, each apex wide, rounded, lateral acclivity broad, shallow, bearing 3 robust setae, midlateral setules diverse.  
 Adult male. Unknown.   
 Distribution. Australia, Tasman Sea, Norfolk Ridge; 707–812 m depth.   
 Etymology. Named for my daughter Alannah Taylor with whom I was pregnant whilst preparing illustrations.   
 Remarks. The following variations from the holotype were observed in the paratypes. The main ventral setae of coxae 1–4 = (20–21)–(21–25)–(18–22)–(42–46). Uropod 1 outer ramus with 3–5 dorsal robust setae, inner ramus 0–3 dorsal robust setae. Uropod 2 outer ramus with 1–6 dorsal robust setae, inner ramus with 1 or without dorsal robust setae.
description: Published as part of Taylor, Joanne, 2006, A new species of Leongathus from the Tasman Sea collected during the 2003 NORFANZ Expedition (Crustacea: Amphipoda: Phoxocephalidae), pp. 207-213 in Memoirs of Museum Victoria 63 (2) on pages 208-213, DOI: 10.24199/j.mmv.2006.63.16, http://zenodo.org/record/12208062