Taxonomy

Discovery and description
The first recorded Malacosteus specimen was collected by Captain Joseph Porter in 1848 in the northwest Atlantic, south of Newfoundland. The fish was found at the surface, probably close to death, and 'made no attempt to escape' when captured. It was presented to the Boston Society of Natural History where it was examined by William Orville Ayres, who named the fish Malacosteus niger (meaning 'soft boned and black'). Ayres described the skeleton as being extremely delicate: 'the bones can be pierced even in their hardest parts by a needle with the greatest ease'. He also noticed the light organ below the eye but was not able to guess its function.

Classification
There has been some reorganisation of the order Stomiiformes with respect to Malacosteus niger since its first discovery and description (Ayers 1848). It was initially placed in its own family, the Malacosteidae, but after a revision of the order (Fink 1985) this was merged with several other families into the Stomiidae. Another more recent revision (Kenaley 2007) examined hundreds of Malacosteus specimens from all over the world and concluded that the following were synonyms of Malacosteus niger:

• Malacosteus indicus
• Malacosteus choristodactylus
• Malacosteus danae

Kenaley also identified a new species from the southern ocean which he named Malacosteus australis, bringing the total number of currently accepted species within the genus to 2.