Eustomias aequatorialis

The <em>Eustomias aequatorialis</em> is a saltwater fish in the family Stomiidae — the loosejaws or barbeled dragonfishes — a group of deep-sea predators renowned for their formidable dentition and bioluminescent capabilities. This species occupies a wide bathymetric range, with records documented from approximately 170 to 2300 metres depth, spanning the mesopelagic and bathypelagic zones of the open ocean. Adults reach a maximum recorded length of around 12.9 cm. Like other stomiids, <em>Eustomias aequatorialis</em> is thought to be a visual predator in dim and dark oceanic environments, likely using photophores — light-producing organs arranged along the ventral surface — for counterillumination camouflage and intraspecific communication. Many stomiids possess a chin barbel used to lure prey. Details of habitat and range for this species remain limited in the ichthyological literature. The name aequatorialis suggests a distribution associated with equatorial oceanic waters, consistent with the broad tropical and subtropical ranges typical of many Stomiidae. Studies of deep-sea dragonfishes depend heavily on trawl sampling during oceanographic expeditions, and the full ecological role of this species in midwater food webs remains to be characterised.