taxonID	type	description	language	source
32248794FFABFFD895FE6A80FD8DF8E5.taxon	description	Figs. 1 – 4; Table 1	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFABFFD895FE6A80FD8DF8E5.taxon	materials_examined	Holotype. USNM 258739, male, 119 mm SL, central north Pacific Ocean, Hawaiian Islands, off Oahu, 21 ° 20 ′ 00 ′′ N, 158 ° 20 ′ 00 ′′ W, 660 – 805 m, R / V Teuthis Cruise V, station 30, 10 - ft opening-closing trawl, 13: 52 – 16: 52, 18 March 1971. New material. SIO 76 - 6, unsexed, 93 mm SL (Fig. 1 A), central north Pacific Ocean, 30 ° 41 ′ 00 ′′ – 30 ° 21 ′ 00 ′′ N, 147 ° 18 ′ 00 ′′ – 147 ° 13 ′ 00 ′′ W, 1200 m wire out, FCRG 71 - 2, Tow 42, Isaacs-Kidd midwater trawl, 19: 00 – 01: 28, 09 November 1971, S. Imsand. USNM 258733, unsexed, 64 mm SL (Fig. 1 D), central north Pacific Ocean, Hawaiian Islands, off Oahu, 21 ° 25 ′ 01 ′′ N, 158 ° 25 ′ 01 ′′ W, 610 – 650 m, El Pescadero III Expedition, R / V Teritu, 10 - ft IsaacsKidd midwater trawl, 10: 56 – 13: 50, 28 February 1971, T. A. Clarke. USNM 320468, likely male, 68 mm SL (Fig. 1 E), central north Pacific Ocean, 27 ° 10 ′ 48 ′′ N, 170 ° 54 ′ 00 ′′ W, 250 m, 19: 36, 19 July 1955, H. M. Smith.	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFABFFD895FE6A80FD8DF8E5.taxon	diagnosis	Diagnosis. Species of Photonectes, subgenus Photonectes s. str. (Prokofiev 2019: 393), unique in postorbital organ shifted forward below orbit, blue luminous tissue on body arranged in two widely spaced interrupted lines between IV photophores and streak-like patch on each side above 10 th to 13 th PV photophores (Figs. 1, 2), and mental barbel with pair of stalked photophore-like structures on distal extremity of its stem (Fig. 3).	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFABFFD895FE6A80FD8DF8E5.taxon	description	Description. Measurements, vertebral, and fin element counts are shown in Table 1. Snout moderate, 1.3 times smaller than eye. Dorsal and anal fins opposed, shifted backward; pelvic fins inserted closer to caudal fin than to snout. Medial fins not covered by skin; pelvic and caudal fins broken at tips. Photophores: BR 9, IP 11 (interspaces between posteriormost three IP photophores approximately 1.5 times greater than previous ones), PV 21, IV 32, OV 20 or 21, VAV 13 (3 over anal-fin base), VAL 11 (2 over anal-fin base), AC 12, IC 57. Blue luminous tissue on body arranged as described for holotype (Prokofiev & Frable 2021) (Figs. 1, 2), but streak-like patch above PV photophores is slightly longer and situated above 10 th to 13 th photophores in two smallest specimens (64 – 68 mm SL) with two small faint round patches posteriorly also not present in larger specimens (Fig. 1 C). In specimen SIO 76 - 6, blue luminous tissue in pectoral area is more developed than in other specimens, forming elongate patch originating above IP- 11 and ending midway between PV- 2 and PV- 3 photophores (Fig. 1 A, B). Postorbital organ long, its anterior half situated below eye (Fig. 1 A). Jaw dentition heterogeneous; premaxillary dentition biserial, with 2 teeth in outer row and 7 – 8 teeth in inner row; teeth in outer row and first tooth in inner row small and pointed, remaining inner teeth long, of unequal size, with barbed tips. Outer premaxillary teeth opposite bases of second and third teeth of inner row. Maxilla bears 7 – 8 moderately long, unequal-length teeth with barbed tips, followed by 9 – 12 smaller, inclined, comb-like teeth with pointed tips. Lower-jaw teeth 26 (SIO 76 - 6 and USNM 320468) or 23 + / 26 (USNM 258733), tips of longer teeth barbed. Vomer with 1 or 2 teeth on each side (anterior largest, posterior potentially a replacement), palatine teeth absent. Basibranchial teeth with two tooth patches, anterior patch with two pairs of sharp conical teeth, posterior patch with two or three pairs of teeth. First ceratobranchial with 7 clusters of denticles, from 1 – 3 each. Gill filaments of first ceratobranchial not reduced, similarly developed along whole length of bone. Posterior process of anguloarticular well-developed. Barbel 1.2 – 1.6 times in head, with thick pigmented stem and thin unpigmented terminal filament ending in bulbous swelling (Fig. 3) (missing in SIO 76 - 6). Terminal filament is 1.9 – 2.3 times longer than stem. Distal extremity of stem unpigmented and possibly luminous, base of luminous tip with internal black pigmentation and pair of stalked photophore-like organs, not as pronounced in SIO 76 - 6.	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFABFFD895FE6A80FD8DF8E5.taxon	discussion	Remarks. In all respects, the new specimens are similar or identical to the holotype of P. klepadloae, showing only slight but invaluable differences in some counts, morphometrics, degree of development of the blue luminous tissue, and in barbel structure. The most obvious is the presence of a bulbous swelling at tip of terminal filament in two smaller specimens, which is lacking in the holotype and SIO 76 - 6. Most probably, the absence of this swelling is an artifact resulting from damage incurred during the collecting haul, as the tip of the filament looks incomplete in the two larger specimens. The general pattern of distribution of the blue luminous tissue is identical in all specimens, although the size of individual patches is somewhat variable between the specimens.	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFABFFD895FE6A80FD8DF8E5.taxon	distribution	Distribution. Photonectes klepadloae is still only known from the central north Pacific Ocean between 21 to 30 ° N and 147 to 171 ° W (Fig. 4).	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFAEFFD395FE6FD1FE50FE07.taxon	description	Figs. 4 – 7; Table 1	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFAEFFD395FE6FD1FE50FE07.taxon	materials_examined	Holotype. ZMMU 23227 (formerly IOM, uncatalogued), unsexed, 150 mm SL (Fig. 5 A), 02 ° 20 ′ N, 128 ° 12 ′ E, R / V Vityaz, cruise 57, station 7276, sample 162, Isaacs-Kidd midwater trawl no. 72, 3300 m wire out, 21: 25 – 22: 25, 23 March 1975. New material. IOM 03639, mature male, 105 mm SL (107 mm SL at time of capture) (Fig. 5 B), western Indian Ocean, off Farquar Island, 10 ° 36 ′ 24 ″ – 10 ° 36 ′ 06 ′ S, 50 ° 01 ′ 48 ″ – 50 ° 13 ′ 54 ″ E, R / V Akademik Kurchatov, cruise 36, station 3750, sample 50, Bongo net no. 8, 200 – 0 m, 400 m wire out, 00: 47 – 01: 07, 11 April 1983.	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFAEFFD395FE6FD1FE50FE07.taxon	diagnosis	Diagnosis. Species of Photonectes, subgenus Photonectes s. str. (Prokofiev 2019: 393), with unique combination of three solid longitudinal bands of blue luminous tissue on ventral surface of body in prepelvic area (Figs. 5 C, 6) and mental barbel with dorsal branch but lacking developed bulbs (Fig. 7 B).	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFAEFFD395FE6FD1FE50FE07.taxon	description	Description. Measurements, vertebral, and fin element counts are shown in Table 1. Snout very short, 1.9 times smaller than eye. Dorsal and anal fins opposed, shifted backward; pelvic fins inserted closer to caudal fin than to snout. Medial fins skinned, tips of pelvic fins broken. Lower lobe of caudal fin 1.4 times longer than upper lobe. Photophores: BR 7, IP 8 + 2, PV 25, IV 35, OV 22, VAV 12 (4 over anal-fin base), VAL 10 + (10 before anal-fin origin, skin missing farther back and some hindmost photophores were apparently lost), AC 11, IC 58. Distance from IP- 1 to top of isthmus as long as combined length of IP series; space between IP- 8 and IP- 9 exceeds space between IP- 9 and IP- 10 by 1.5 times. Three solid longitudinal bands of blue luminescent tissue on ventral surface of body. Thick, sharply delimited midventral band is conspicuous on isthmus originating behind base of barbel, becoming indistinct in posterior half of IP series and apparently disappearing behind IP- 8. Paired ventrolateral bands originate at IP- 2 as thin inconspicuous lines running outward from IP series of photophores becoming much thicker and conspicuous from shoulder-girdle region on lowermost flank, twice as close to PV than OV series of photophores, disappearing in front of pelvic-fin origin. Unpaired midventral band originates behind level of shoulder girdle (traceable from PV- 5) and extends along midventral line to pelvic-fin origin (Figs. 5 C, D, 6). Skin at midline of breast abraded, making it unclear if midventral bands on isthmus and vent are continuous (Fig. 6). No other luminous tissue on head, body or inside mouth. Postorbital organ 1.3 times longer than eye, lacking anteroventral extension of jet-black tissue encircling photogenic gland (Fig. 7 A). Jaw dentition heterogeneous (Fig. 7 A); premaxillary dentition biserial, with 2 + 1 teeth in outer row and 6 teeth in inner row; teeth in outer row and first tooth in inner row small and pointed, remaining inner teeth long, of unequal size, with barbed tips. First two teeth in outer row opposite space between second and third teeth of inner row; third tooth opposite space between fourth and fifth inner teeth. Maxilla bears 9 / 10 needle-like teeth of unequal length with barbed tips followed by 14 / 13 smaller, inclined, comb-like teeth with pointed tips. Lower-jaw teeth 34 / 37, longer teeth weakly barbed. Vomer possesses pair of long barbed teeth on each side, outer teeth longer than inner one. Each palatine with two smaller, closely spaced teeth with barbed tips, hind tooth longer. Basibranchial teeth in two groups, 2 + 2 teeth per group, posterior pair of teeth in each group longer than anterior pair. First ceratobranchial bears six clusters of small denticles, 1 – 3 denticles per cluster. Gill filaments of first ceratobranchial are similarly developed along whole length of bone, not extending behind gill cover. Posterior process of anguloarticular welldeveloped (Fig. 7 A). Barbel 1.8 times in head, reaching interspace between IP- 2 and IP- 3 when adpressed, lacking bulbs, with short dorsal branch, 9 times in barbel length. Barbel terminates in small oval swelling. Tips of distal swelling and of dorsal branch each bear minute bulblet; bulblets at base of terminal swelling are poorly developed. Entire barbel and its dorsal branch darkly pigmented except small pale (probably luminous) area on stem slightly (1.25 times) closer to base of dorsal branch than to base of barbel (Fig. 7 B).	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
32248794FFAEFFD395FE6FD1FE50FE07.taxon	discussion	Remarks. The new specimen shows a unique arrangement of blue luminous tissue on the body but otherwise is similar to the holotype of P. litvinovi. The latter shows no blue tissue but its skin is largely abraded (Fig. 5 A); thus, this difference likely represents an artifact of damage during collection. For other characters, the new specimen is almost identical to the holotype of P. litvinovi. Minor differences include the presence of an additional tooth in the outer row of the premaxilla, a greater number of dentary teeth (34 – 37 vs. 29), a much longer barbel (1.8 vs. 3.3 times in head) with a short transparent area on its stem (absent in the holotype) and scarcely expressed bulblets at base of distal swelling. The length of barbel is a size-dependent character, as documented for other species within the genus (Prokofiev 2019), whereas the other differences are likely individual variation. Since the blue luminous tissue was not formerly documented for that species, its identification might be problematic using the existing keys (Prokofiev 2019; Prokofiev & Frable 2021). The latest key for the species of the genus in Prokofiev & Frable (2021) can be modified in the following manner to include the correct diagnostic information for P. litvinovi.	en	Prokofiev, Artem M., Frable, Benjamin W. (2023): New specimens and supplementary descriptions of two rare dragonfishes Photonectes klepadloae and P. litvinovi, with comments on the distribution of P filipendulus (Teleostei: Stomiidae: Melanostomiinae). Zootaxa 5228 (4): 489-500, DOI: https://doi.org/10.11646/zootaxa.5228.4.7
