Species of the deep-sea stomiid fish genus Malacosteus have enormous jaws, a single round nostril on each side of the snout, a large tear-shaped accessory reddish light organ below the front margin of each eye, and reduced serial photophores. They lack a membrane between the bones of the lower jaw and have no palatine teeth. The genus contains two species, both found in Australian waters.
The tear-shaped light organ in front of the eye emits a red light, and Malacosteus is one of three stomiid genera with photophores that produce red light. Species have evolved extremely specialized visual pigments capable of seeing this red light.of deep-sea fishes that can see red light. This gives Malacosteus a distinct advantage over prey which cannot see the long wavelength light emitted by the light organ - kind of like dishes having "night-vision" goggles.
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