| Family | Scientific Name | Author | Year | Common Name |
| Stomiidae | Malacosteus niger | Ayres | 1848 | Stoplight Loosejaw |
Family Malacosteidae (genera Aristostomias, Malacosteus, and Photosotomias) – Mouth large, jaws longer than skull, about 15-30% standard length; membranes forming floor of mouth absent. Chin barbel present or absent. Dorsal fin located well posteriorly, directly above anal fin. Dorsal and ventral adipose fins absent. Postorbital photophore prominent, located posteroventrally to eye (FAO 2002).
Malacosteus niger
Unique Characteristics: Body without scales or hexagonal scale pockets. Dorsal and anal fins located near caudal fin; adipose fin absent. Dorsal and anal-fin bases approximately equal, or anal-fin base longer than dorsal. Mouth lacks floor, lower jaws not connected by membrane. Pectoral fins present; 2 rows of photophores on each side of isthmus. Chin barbel absent; snout shorter than eye diameter (FAO 2020).
Similar Species: None
References:
FAO. 2002. The living marine resources of the Western Central Atlantic. Volumes 1-3. K.E. Carpenter (ed.). Food and Agriculture Organization of the United Nations, Rome, Italy. 4099 pp. http://www.fao.org/3/y4160e/y4160e00.htm.
(FAO 2020) Sutton, T.T., P.A. Hulley, R. Wienerroither, D. Zaera-Perez, and J.R. Paxton. 2020. Identification guide to the mesopelagic fishes of the central and south east Atlantic Ocean. FAO Species Identification Guide for Fishery Purposes. Rome, FAO. 327 pp. https://doi.org/10.4060/cb0365en.