Gigantactis

Gigantactis is a genus of deep-sea fish of the family Gigantactinidae, first described in 1902 by August Brauer. The species in this genus are poorly known and found in all oceans, at depths of 1000 - 2500 m. The most striking feature of these fish is extremely enlarged first filament of dorsal fin, called the illicium, with bioluminescent photophore at its end. (In G. longicauda the length of the illicium can be up to 3.3 times the standard length of the fish.) The genus name, Gigantactis, derives from the Greek, gigas (gigantic ) and aktis (ray), describing the genus by its long dorsal-fin spine which serves as a lure.

Species
As of 2024, there are currently 22 recognized extant species in this genus:
 * Gigantactis balushkini Kharin, 1984
 * Gigantactis cheni H. C. Ho & K. T. Shao, 2019
 * Gigantactis elsmani Bertelsen, Pietsch & Lavenberg, 1981 (Elsman's Whipnose)
 * Gigantactis gargantua Bertelsen, Pietsch & Lavenberg, 1981 (Gigantic Whipnose)
 * Gigantactis gibbsi Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis golovani Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis gracilicauda Regan, 1925
 * Gigantactis herwigi Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis ios Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis kreffti Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis longicauda Bertelsen & Pietsch, 2002
 * Gigantactis longicirra Waterman, 1939
 * Gigantactis macronema Regan, 1925
 * Gigantactis meadi Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis microdontis Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis microphthalmus Regan & Trewavas, 1932
 * Gigantactis paresca Rickle, 2024
 * Gigantactis paxtoni Bertelsen, Pietsch & Lavenberg, 1981 (Paxton's whipnose)
 * Gigantactis perlatus Beebe & Crane, 1947
 * Gigantactis savagei Bertelsen, Pietsch & Lavenberg, 1981
 * Gigantactis vanhoeffeni A. B. Brauer, 1902 (Cosmopolitan whipnose)
 * Gigantactis watermani Bertelsen, Pietsch & Lavenberg, 1981