View data on Catalog of Fishes here.
Vertebrae 32(31–33)+15(14–16)=47(46–48). Maximum body depth 6.0(4.9–6.2) times in SL. Caudal peduncle depth 2.4(2.1–2.5) times in its length. Head length 4.0(3.8–4.1) times in SL. Eye diameter in males 3.5(3.5–3.9) times in head length; in females, 0.9–4.5); in immature specimens, (4.0–5.1). Chin barbel well developed in small specimens SL 36–52 mm, slightly larger or slightly smaller than–head length (fits 0.8–1.4 times in head length); in large specimens SL 71–97 mm, chin barbel reduced and 1.8 to 2.4 times in head length; terminal bulb small, droplet-like, well pronounced only in small specimens. Comb-like row of teeth on maxilla with 33(13–27) slanted teeth, 5(5–7) teeth present on palatine, 14(15–16) gill teeth present on first gill arch.
Dorsal-fin rays 15(14–17), anal-fin rays 14(12–15). pectoral-fin rays 8(7–9). Length of dorsal fin base in 2.1 (1.8–2.5) times greater than that of anal fin. Origin of anal fin at vertical through third (first to third) terminal ray of dorsal fin. Pelvic-fin bases reach vertical through origin of dorsal fin (same or not reaching it). Dorsal adipose fin originates above II the 10th–12th) anal fin ray, ventral adipose fin below 14th(13th–14th) photophore of VAV series.
Photophores: BR 18(17–19); IP 9(9). PV 13(12–13), VAV 19(17–19), AC 11(10–12), IC 52(50–52); OV 13(11–13), VAL 19(19–22), OA 32(31–33). Interphotophore spaces exceed their diameter by five to six times. Second photophore of PV series above third photophore. Two median AC photophores (fifth–sixth) elevated relative to others. Three luminous spots present on upper jaw. first spot round, relatively large; two other spots elongated and spindle–like, significantly smaller than first one. Numerous spot-like aggregations of luminous tissue on body. Granular, longitudinally oriented luminous spot with uneven margins present posterior to operculum at eye level; its length 0.8(0.6–1.0) of eye diameter. Small, numerous, often fused spots present on the body, forming horizontal rows in three areas: (1) below dorsal fin and above lateral row of photophores, in holotype, 18 spots found on left side and 15 on right (in large paratypes 11–37 spots on one side); (2) between lateral and ventral rows of photophores, in holotype, 19 spots found on left side and 18 spots on right (in paratypes, 16–22 spots); and (3) in front of pelvic fins, between lateral and ventral rows of photophores. In holotype, seven spots on left side and ten spots on right (in paratypes, 10–15).
Development of aggregations of luminous spots on body occurs as follows: juveniles SL 23–35 mm do not have any luminous spots; at SL> 35 mm, first spots appear on upper jaw; at SL> 40 mm. luminous spots develop above ventral row of photophores, with simultaneous development of a spot behind operculum. Full complement of luminous spots attained at SL of about 80 mm.
Background coloration dark brown with silvery tint on sides.
Three luminous spots on upper jaw, with anterior spot significantly larger than others. Enlarged spot of irregular shape found posterior to operculum at eye level (its length not exceeding eye diameter); numerous small luminous spots, forming horizontal rows below dorsal fin above lateral row of photophores and between this row and ventral photophore row. Additional row of luminous spots present above ventral photophore row between pectoral and pelvic fins. Vertebrae 46–48; photophores IC 50–52, OA 31–33. Chin barbel at SL < 50 mm with terminal bulb, 3.9–5.4 times in SL, at SL > 70 mm chin barbel without bulb, very short, 6.7–9.6 times in SL. Body depth 4.9–6.2 times in SL. Body dark brown.
Astronesthes decoratus is found between 11°N and 17°S in the eastern equatorial Atlantic.
Parin NV, Borodulina OD. 2002. Preliminary review of Astronesthes niger species group (Astronesthidae, Stomiiformes) with description of six new species from the Atlantic and Indian Oceans. Voprosy Ikhtiologii 42(4):437–458.
Astronesthes decoratus is a member of the A. niger species group. The following description, based on Parin and Borodulina’s (2002) revision, applies to all species in the group.
Maximum body depth 4.9–6.7 times in SL. Caudal peduncle depth 1.9–2.6 times in its length. Vertebrae (31–35)+(14–16)= 46–50. Head length 3.3–5.0 times in SL. Eye diameter 3.3–5.5 times in head length. Chin barbel small (0.7–3.5 times in head length), its length decreasing with growth. Terminal bulb usually well developed in juveniles (its shape often species specific), but disappearing in majority of species with growth. Premaxilla with five fangs in main row and two to three small lateral teeth. Comb-like row of teeth on maxilla bearing 11–33 teeth, number increasing with growth. One tooth present on anterior head of each vomer. A row of five to eight teeth on palatines. Gill teeth 14–17 on first gill arch.
Dorsal-fin rays 14–17, A (rarely 12) 13–15, pectoral-fin rays 7–9 (usually eight). Pelvic fin bases situated just in front of vertical at beginning of dorsal fin, sometimes slightly more posteriorly. Beginning of anal fin at level of three posteriormost rays of dorsal fin or posterior to end of its base. Dorsal fin base length 1.7–2.5 times greater than that of anal fin. Dorsal adipose fin originates above 9th to 12th anal–fin ray; ventral adipose fin below 12th to15th photophore of VAV series.
Photophores: BR 17–19(rarely 20), IP 9, PV 12–15, VAV 17–21, AC 10–12, IC 50–55(rarely 56); OV 11–14(rarely 15), VAL 19–22, OA 31–35(rarely 36). Serial photophores of average size, with interphotophore spaces four to six times greater than photophore diameter in adults. Ventral row forming steep curve below base of pectoral fin; three posteriormost photophores of IP series increasingly elevated and three anteriormost photophores of PV series usually steeply descending to level of remaining photophores of ventral row. In AC series. first photophore often elevated compared to others, middle one or two photophores also elevated. Numerous additional photophores present on head and body. In small specimens (SL 30–60 mm), these photophores occur along ventral body margin in regular rows that gradually disappear with growth.
Spots of luminous tissue present on head and body. On upper part of head of small specimens (SL 30–50 mm), spots conspicuous between nostrils, above both orbits, and on nape region. Spots becoming more sparse in adults, transforming into aggregations of separate small "scales" of luminous tissue. There are one to three luminous spots on the skin covering the premaxilla in front of anterior margin of orbit and below anterior part of orbit.
Skin under or covering anterior margin of anterior spot (single or largest one) strongly pigmented; second and third spot, if present, significantly smaller with a more simple morphology. In anterodorsal part of operculum, small spot of luminous tissue present, which is also well distinct in small specimens, but transforming in adults into aggregation of dispersed luminous scales. Luminous spot present on body (large or small), situated posterior to operculum and appearing at a standard length of 40–70 mm. Aggregation of luminous tissue can be found above lateral photophore row below dorsal fin, between lateral and ventral rows below bases of pectoral fin, in front of pelvic fin base.
Postorbital light organ below middle part of orbit or further posteriorly and separated from orbit by dark pigment fold; organ sexually dimorphic, as in other species of the genus. In females, this light organ is small and rounded; in males, significantly larger and oval. Photogenic gland very small, found in middle of light organ in females and in posterior part in males.
Body black, fading to brown or beige in preservative. Fin membranes lightly colored, rays slightly pigmented. Chin barbel (including terminal bulb) with pigment only on anterior part of base; thin and pigmented stem visible inside barbel.
Parin NV, Borodulina OD. 2002. Preliminary review of Astronesthes niger species group (Astronesthidae, Stomiiformes) with description of six new species from the Atlantic and Indian Oceans. Voprosy Ikhtiologii 42(4):437–458.
Atlantic, 1°04'N, 18°22'W, depth 2100 meters.
Holotype: USNM 357364.
