Latin name

Photostomias guernei

Other name

Ultimostomias mirabilis

Identification

The body shape of Photostomias guernei is elongated. This species is distinguished by the presence of 2 pairs of basibranchial tooth patches. The length of the postorbital organ in males is moderate; in specimens larger than 6.0 cm, it measures 45.5-144.5% of the fleshy orbit length and 7.8-28.1% of the jaw length (JL). The length of the anterior orbital organ in males is also moderate; in specimens over 6.0 cm, it measures 4.5-21.7% of the fleshy orbit length and 0.8-4.9% of the JL.

Features of fish fins

Dorsal soft rays (total): 22-28; Anal soft rays: 25-32. The sum of the dorsal and anal fin rays is 50-56.

Fish colouring

The head and body of Photostomias guernei are black, without any spots or lines.

Distribution

Distributed in the Western Atlantic: from the USA to the Gulf of Mexico; records exist from the Antilles. Eastern Atlantic: from southern Portugal to Mauritania. Northwest Atlantic: Canada. Indo-Pacific region: in tropical and temperate areas. Southeast Pacific: Chile.

Habitat

A marine, bathypelagic, deep-sea species. Its depth range is from 1,138 to 3,100 meters.

Size

Adults of this species can reach a maximum length of approximately 16 centimeters.

Behavior

This species exhibits an asynchronous diel vertical migration pattern. During the day, the fish resides in the lower mesopelagic zone (below 500 meters), and at night, it disperses upwards. They hide from predators by concealing themselves in crevices and depressions.

Food and feeding habits

The diet of Photostomias guernei consists primarily of other mesopelagic fishes and some crustaceans.

Reproduction

Research indicates that male Photostomias guernei have better vision than females. It is hypothesized that acute vision in males is necessary to detect the dimmer bioluminescent signals of females.

Fishing

This species is not commercially important.

Relationship with a person

Harmless.