Representatives of the Argentiniformes order are small pelagic sea fishes belonging to the Protacanthopterygii superorder. The Osmeriformes order, which included Argentiniformes until recently, as well as the Salmoniformes order and the Esociformes order belong to this superorder.
Argentiniformes are found in all oceans and comprise six families, about 60 genera, and almost 230 fish species.
Argentiniformes are mostly deep-sea fish. Macropinna microstoma, the representative of the order belonging to the Opisthoproctidae family and inhabiting the depths from 600 to 800 meters in the North Pacific Ocean, is distinct in astonishing look. These unusual fish have a transparent head through which they can see with their tubular eyes. Macropinna microstoma was described in 1939 for the first time, but the first photos of live fish were taken only in 2004.
(Macropinna microstoma Photo by © Monterey Bay Aquarium Research Institute (MBARI). orbi.kr)
4 species of the Argentiniformes order, representatives of two families (Argentinidae and Microstomatidae) of the Argentinoidei suborder, inhabit the Adriatic Sea.
Argentine (Argentina sphyraena).
(Argentine. Photo © Ichthyology Database of the Swedish Museum of Natural History. artedi.nrm.se / fishbase.org)
It is a pelagic schooling species. It inhabits the depths of 50-700 meters. The maximum recorded length is 35.5 cm, specimens about 20 cm long are more common. It feeds on planktonic organisms, mollusks, crustaceans, as well as medium-sized fish. It is a permanent, but rather rare inhabitant of the Adriatic Sea. It is more common in the southern part of the sea.
Smalltoothed argentine (Glossanodon leioglossus).
(Smalltoothed argentine. Photo by © Mariano García Rodriguez. fishbase.org)
It inhabits the depths of 150-400 meters. It keeps to the bottom of the shelf. The maximum recorded length is 20 cm; specimens up to 10 cm are more common. It feeds on pelagic crustaceans. It is a rare inhabitant of the Adriatic Sea, mostly of its southern part.
Slender argentine (Microstoma microstoma).
(Slender argentine. Photo © ilmaredamare.com)
It is a pelagic deep-sea single fish. The maximum recorded length is 21 cm. It feeds on zooplankton. It is a rare inhabitant of the Adriatic, it occurred in the southern part of the sea several times.
Mediterranean large-eyed argentine (Nansenia oblita).
(Mediterranean large-eyed argentine. Photo by © Henk Heessen. marinespecies.org)
It is a pelagic species. It inhabits the depths of 300-500 meters. The maximum recorded length is 18 cm. It feeds on zooplankton. It is a rare inhabitant of the Adriatic Sea. It is found in the southern part of the sea.