Although little is known about this species, A. illuminatus is most likely a diel vertical migrator, inhabiting the mesopelagic zone during the day and the epipelagic at night.
See data for A. illuminatus in the Catalog of Fishes.
The body of A. illuminatus is relatively elongate with a body depth of approximately 15% SL; its head is large, 20-23% SL. The jaws are large with both the upper and lower jaw containing moderately long, fang-like teeth. As with all members of the genus Astronesthes, the maxilla bears numerous comb-like teeth. The eye is relatively large, from 20–26% HL and larger in males than in females. The chin barbel is relatively short, from 6–110% HL and much smaller in large than in small specimens. The terminal bulb is an elongated ovular mass. The ventrolateral photophores are evenly and closely spaced with the IV photophores forming a deep curve under pectoral fin. The middle 1 or 2 AC photophores are raised above the others in the series. The posterior trunk of the body and caudal peduncle is scattered with patches of luminescent tissue. The largest dorsal patch begins posterior to dorsal adipose fin and the largest ventral patch begins over the last few rays of anal fin. The posterior luminescent patches often obscure the last few AC photophores. The postorbital photophore is minute. The skin is smooth, black and without scales or hexagonal patterns. Both a dorsal and ventral adipose fin are present.
Astronesthes illuminatus is a member of the A. boulengeri-species group and most readily distinguished form other members of the group, including A. boulengeri, by the size and position of the caudal luminescent patches.
This species has pelagic eggs and larvae.
Astronesthes illuminatus is a species of the southern subtropical convergence zone; likely circumglobal in this water mass
Mesopelagic during the day, epipelagic at night. 120–2000 m.
Parin N, Borodulina O, Hulley P. 1999. A Review of the Astronesthes boulengeri Species Group (Astronesthidae, Stomiiformes) with Description of Two New Species. Journal of Ichthyology 39(8):557–570.
Attains a length of 155 mm SL.
As with many members of the family Stomiidae, species of the genus Astronesthes likely use their bioluminescent hyoid barbels to lure prey to the mouth.
31°01'S, 47°39'E, depth 2000 meters.
Holotype: ISH 1553-1968. Paratypes: ISH 561-1976 (3), 721-1976 (2), 1957-1968 (1), 1386-1971 (5), 679-1976 (5), 561-1976 (2); USNM 348597 (1), 348599 (1).
