taxonID	type	description	language	source
03FA881D4C02FFF742DFFB50A790FE16.taxon	materials_examined	Holotype: NMNZ P. 043195; 55.5 mm; RV James Cook Sta. JCO 8610 / 022; Hikurangi Trough, off Hawke’s Bay 39 o 58.4 ' S, 177 o 38.8 ' E; 22 Aug. 1986, 1140 hrs; FMMWT 952 m max. depth. Paratypes: n = 26 (27.2 – 61.3 mm SL) NMNZ P. 008978; (2 specimens, 43.2 & 61.3 mm SL); RV James Cook Sta. JCO 7913 / 021; East of Mahia Peninsula, east coast North Island. 39 o 01.0 ' S, 178 o 27.1 ' E; 1 Oct. 1979, 2325 hrs; FMMWT 30 m max. depth. NMNZ P. 031575; (1 sppm., 61.0 mm SL); RV James Cook Sta. JCO 8610 / 020; Hikurangi Trough, off 40 o 20.7 ' S, 178 o 18.4 ' E; 21 Aug. 1986, 1414 hrs; FMMWT 1000 m max. depth. NMNZ P. 043196; (3 specimens, 32.2, 32.7 & 33.0 mm SL); RV James Coo k Sta. JCO 8109 / 068; Poverty Sea Valleys, Hikurangi Trough. 39 o 09.9 ' S, 179 o 07.4 ' E; 4 Jun. 1981, 2258 hrs; FMMWT 30 m max. depth. NMNZ P. 043197; (2 specimens, 41.1 & 43.7 mm SL); RV James Cook Sta. JCO 8516 / 003; central Tasman Basin. 43 o 07.8 ' S, 159 o 28.2 ' E; 15 Oct. 1985, 2067 hrs; FMMWT 50 m max. depth. NMNZ P. 043198; (2 specimens, 32.0 & 55.2 mm SL); RV James Cook Sta. JCO 8109 / 067; Poverty Sea Valleys, Hikurangi Trough. 39 o 09.5 ' S, 179 o 09.3 ' E; 4 Jun. 1981, 2141 hrs; FMMWT 60 m max. depth. NMNZ P. 043199; (1 sppm., 28.4 mm SL); RV James Cook Sta. JCO 8610 / 105; Ritchie Banks, Hikurangi Trough. 39 o 40.3 ' S, 178 o 22.3 ' E; 5 Aug. 1986, 1430 hrs; FMMWT 680 m max. depth. NMNZ P. 043201; (1 sppm., 37.9 mm SL); RV James Coo k Sta. JCO 8611 / 071; Taranaki Bight, west of Cape Taranaki. 38 o 59.7 ' S, 172 o 00.0 ' E; 25 Sep. 1986, 1840 hrs; FMMWT 255 m max. depth. NMNZ P. 043202; (1 sppm., 31.3 mm SL); RV James Cook Sta. JCO 8611 / 069; north – east Challenger Plateau. 39 o 26.5 ' S, 171 o 00.9 ' E; 25 Sep. 1986, 0252 hrs; FMMWT 96 m max. depth. NMNZ P. 043204; (5 specimens, 27.3, 29.2, 30.9, 32.1 & 32.2, mm SL); RV James Cook Sta. JCO 8611 / 068; north – east Challenger Plateau. 39 o 28.7 ' S, 171 o 01.7 ' E; 25 Sep. 1986, 0143 hrs; FMMWT 58 m max. depth. NMNZ P. 043205; (5 specimens, 31.4, 32.1, 32.9, 32.9 & 35.96 mm SL); RV James Cook Sta. JCO 8611 / 065; Challenger Plateau north – west of Cape Farewell. 39 o 51.7 ' S, 171 o 01.8 ' E; 24 Sep. 1986, 2048 hrs; FMMWT 23 m max. depth. NMNZ P. 043229; (2 specimens, 21.3 & 28.0 mm SL); RV James Cook Sta. JCO 8008 / 076; East Cape Ridge. 38 o 31.3 ' S, 179 o 37.2 ' E; 24 Apr. 1986, 1913 hrs; FMMWT 150 m max. depth. NMNZ P. 054996; (1 sppm., 40.7 mm SL); RV James Cook Sta. JCO 8616 / 006; northern central Tasman Basin. 40 o 11.7 ' S, 160 o 1 2.5 ' E; 16 Oct. 1985, 2029 hrs; 2 x 2 plankton net 50 m max. depth. Additional non-type material: (n = 8) NMNZ P. 008922; (2 specimens, 34 & 38 mm SL); R / V James Coo k Sta. JCO 7913 / 009; East Cape Ridge. 38 o 22.1 ' S, 178 o 57.1 ' E; 30 Sep. 1979, 2320 hrs; FMMWT 30 m max. depth. NMNZ P. 008970; (1 sppm., 28 mm SL); R / V James Cook Sta. JCO 7815 / 023; Southern Challenger Plateau. 41 o 43.7 ' S, 171 o 19.4 ' E; 26 Aug. 1978, 0820 hrs; BONGO net 100 m. NMNZ P. 043194; (3 specimens 31.5, 32.1 & 33.0 mm SL); RV James Cook Sta. JCO 8109 / 079; southern Kermadec Trench off East Cape. 38 o 21.0 ' S, 179 o 16.1 ' E; 5 Jun. 1981, 2022 hrs; FMMWT 30 m max. depth. NMNZ P. 043200; (2 specimens, 30.6 & 33.7 mm SL); R / V James Cook Sta. JCO 8109 / 081; East Cape Ridge. 38 o 20.3 ' S, 179 o 15.8 ' E; 5 Jun 1981, 2240 hrs; FMMWT 30 m max. depth.	en	Clements, Kendall D., Stewart, Andrew L. (2026): A new species of Lampanyctus (Myctophiformes: Myctophidae) from the western South Pacific Ocean. Zootaxa 5782 (2): 361-368, DOI: 10.11646/zootaxa.5782.2.7, URL: https://doi.org/10.11646/zootaxa.5782.2.7
03FA881D4C02FFF742DFFB50A790FE16.taxon	diagnosis	Diagnosis: Lampanyctus mendeleevi may be distinguished from all other Lampanyctus species by the following combination of characteristics: pectoral fin long, reaching to or just past anal-fin origin; no cheek photophores; no luminous gland at the base of the adipose fin; SAO 3 directly above AOa 1; anal fin usually with 15 – 16 rays; the infracaudal gland occupies the entire length of the caudal peduncle, and is dorsally expanded to be in contact with or less than ½ a photophore diameter away from the AOp series (see figure 3). For comparative diagnosis see discussion.	en	Clements, Kendall D., Stewart, Andrew L. (2026): A new species of Lampanyctus (Myctophiformes: Myctophidae) from the western South Pacific Ocean. Zootaxa 5782 (2): 361-368, DOI: 10.11646/zootaxa.5782.2.7, URL: https://doi.org/10.11646/zootaxa.5782.2.7
03FA881D4C02FFF742DFFB50A790FE16.taxon	description	Description: Measurements (% SL) Holotype, range and mean of paratypes in parentheses: HL 28.3 (25.4 – 31.5, ¯ x 28.7); UJL 20.0 (17.4 – 23.2, ¯ x 20.8); ED 8.3 (6.1 – 8.2, ¯ x 7.3); HD 19.6 (17.6 – 20.4, ¯ x 19.3); BD 20.0 (17.0 – 21.4, ¯ x 18.7); DF 16.0 (13.1 – 16.9, ¯ x 15.1); AF 19.6 (18.1 – 21.4, ¯ x 19.4); LCP 22.5 (16.4 – 21.9, ¯ x 19.4); DCP 9.5 (8.0 – 11.1, ¯ x 9.4); PD 47.9 (45.8 – 52.8, ¯ x 48.6); PV 43.4 (40.4 – 46.1, ¯ x 43.0); PP 29.4 (28.4 – 32.9, ¯ x 30.7); PA 58.0 (55.9 – 61.6, ¯ x 57.8); Pad 79.3 (75.7 – 82.1, ¯ x 78.8). Meristic characters: Holotype, paratypes plus additional eight specimens in parentheses D 12 (12 – 14); A 16 (15 – 17); P 14 (12 – 15); AO 6 (6 – 8) + 8 (6 – 8), total 14 (13 – 15); GR 4 (4 – 5) + 1 + 9 (8 – 10), total 14 (13 – 15); LLO 35 (33 – 36). Body elongate, but deeper-bodied than most other Lampanyctus; head relatively large (~ 28 % SL); body laterally compressed, particularly at caudal peduncle. Premaxillaries and dentaries with closely set, villiform teeth; inner series of teeth at rear of premaxillaries and dentaries more regularly spaced and slightly larger. Series of 4 – 5 laterally compressed, anteriorly pointing teeth at rear of dentary. Minute teeth are present on the palatines, vomer heads and entire exposed ventral surface of the mesopterygoid. Head length 3.5 (3.2 – 3.9, ¯ x 3.4) in SL. Mouth large, oblique, upper jaw 1.4 (1.3 – 1.6, ¯ x 1.4) in HL and 5.0 (4.3 – 5.9, ¯ x 4.8) in standard length. Eyes large, diameter 2.4 (2.2 – 3.6, ¯ x 2.9) in UJL and 3.4 (3.3 – 5.2, ¯ x 3.9) in HL. Origin of dorsal fin behind base of pelvic fin; origin of anal fin under posterior 40 % of dorsal fin. Pectoral fins moderately long, reaching anal-fin origin; pelvic fins extending to origin of anal fin. Origin of adipose fin slightly behind last anal-fin ray. No photophores on cheek, no luminous gland at origin of adipose fin and no secondary photophores on head and trunk. Dn absent; Vn small. Op 1 below posterior end of jaw; Op 2 slightly above level of base of pectoral insertion and about above Op 1. PLO in advance of pectoral base, position highly variable from slightly above midway pectoral fin and lateral line to almost touching lateral line (PLO — pectoral fin / PLO — lateral line ratio 1.2 – 5.6, ¯ x = 2.6). PLO position may in fact vary from one side of the fish to the other. PVO 1 slightly behind PVO 2 and below lower base of pectoral fin; line PVO 1 – PVO 2 passing anterior to PO 2; PVO 2 almost at upper pectoral base. Five PO, with PO 4 highly elevated to level between PVO 1 and PVO 2 and a little behind PO 3. VLO behind base of pelvic fins and approximately midway between lateral line and ventral base (VLO — pelvic-fin base / VLO — lateral line ratio 0.7 – 1.4, ¯ x = 1.0). Four VO, VO 2 sometimes raised but not anteriorly displaced. SAO series angulate; SAO 1 varies from slightly ahead of VO 3 to slightly behind, and is either level with or below SAO 2; line SAO 3 – SAO 2 passing through or slightly ahead of VO 4, with SAO 2 above anus and SAO 3 above origin of anal fin (and AOa 1) at lateral line. AOa series varies from level to moderately arched. Pol 1 behind last AOa, line Pol 2 – Pol 1 touches last AOa; Pol 2 at lateral line, well in front of adipose origin. No AOp above anal-fin base; AOp in contact with or less than one half photophore diameter away from infracaudal gland. Prc continuous with AOp; Prc 1 – 2 and Prc 2 – 3 spacings equal. Prc 2 below level of Prc 1, and Prc 4 slightly posterior to Prc 3 and at level of lateral line. Supracaudal gland short, consisting of 3 overlapping scales; infracaudal gland longer, extending along entire caudal peduncle from procurrent caudal rays to last anal-fin ray, consisting of 7 or 8 overlapping scales. Infracaudal scales considerably enlarged, being as much as 3 – 4 AOp photophore diameters deep (Fig. 3). Size: The largest specimen measured was 61.3 mm SL. Seven of the 40 specimens measured for this study were 50 mm SL or more, however all these fish are from waters east of New Zealand. Lampanyctus mendeleevi from the Tasman Sea and Australian waters do not appear to grow larger than 50 mm SL (J. Paxton pers. comm., 2011).	en	Clements, Kendall D., Stewart, Andrew L. (2026): A new species of Lampanyctus (Myctophiformes: Myctophidae) from the western South Pacific Ocean. Zootaxa 5782 (2): 361-368, DOI: 10.11646/zootaxa.5782.2.7, URL: https://doi.org/10.11646/zootaxa.5782.2.7
03FA881D4C02FFF742DFFB50A790FE16.taxon	distribution	Distribution: Lampanyctus mendeleevi is widespread in waters north of the subtropical convergence in the Australasian region, from Western Australia, South Australia, Tasmania, Victoria, the Kermadec Is. and New Zealand. New Zealand material is found from off North Cape to the Puysegur Bank (Fig. 4). Probably more widespread but its small size means it is not often caught, or recognised as unique. Appears to undertake a diel migration; specimens taken at night were in 23 – 250 m depth whereas those during daylight hours were in 255 – 1000 m; the former probably caught in the ascending layer. One daytime winter catch in 100 m was taken probably in the descending layer.	en	Clements, Kendall D., Stewart, Andrew L. (2026): A new species of Lampanyctus (Myctophiformes: Myctophidae) from the western South Pacific Ocean. Zootaxa 5782 (2): 361-368, DOI: 10.11646/zootaxa.5782.2.7, URL: https://doi.org/10.11646/zootaxa.5782.2.7
03FA881D4C02FFF742DFFB50A790FE16.taxon	etymology	Etymology: The species is named after the Soviet Research Vessel Dmitri Mendeleev. This name was proposed by Basil Nafpaktitis, who first recognized it as a distinct taxon while working in New Zealand in the early 1980 s.	en	Clements, Kendall D., Stewart, Andrew L. (2026): A new species of Lampanyctus (Myctophiformes: Myctophidae) from the western South Pacific Ocean. Zootaxa 5782 (2): 361-368, DOI: 10.11646/zootaxa.5782.2.7, URL: https://doi.org/10.11646/zootaxa.5782.2.7
