Nearly nothing is known about the only extant shark of the Trigonognathus genus, the Viper Dogfish. Part of the Lanternshark family, its snake-like mouth filled with crooked nail-like teeth sets it apart from other Etmopterus, whose mouths of fork-and-knife dentition sit further back from the snout. While the body, fins, spines and bioluminescent flanks of the Viper Dogfish are consistent with Lanternshark morphology, its mouth is triangular like a Frilled shark’s, possibly able to extend to snatch and swallow large boney fish and crustaceans like a Goblin shark. This deep-water Lanternshark has only been recorded four times by biologists and researchers, leaving the function of its unique mixture of features a mystery to science.
Distribution: North and central Pacific, Japan, Taiwan and Hawaiian Islands.
Habitat: On bottom, upper continental slopes around 250 to 1000 meters deep. Possibly also oceanic.
Biology: Viviparous with litters possibly of 25-26 pups. Feeds on bony fishes.
Status: IUCN Red List: Data deficient, possibly rare.
*Brought to you by Sharks of the World, 2014.
Other sources: Mochizuki, K., & Ohe, F. (1990). Trigonognathus kabeyai , a new genus and species of the squalid sharks from Japan. Ichthyological Research, 36(4), 385–390. http://doi.org/10.1007/BF02905456
Shirai, S., & Okamura, O. (1992). Anatomy of Trigonognathus kabeyai , with comments on feeding mechanism and phylogenetic relationships (Elasmobranchii, Squalidae). Ichthyological Research, 39(2), 139–150. http://doi.org/10.1007/BF02905997
Wetherbee, B. M., & Kajiura, S. M. (2000). Occurrence of a rare squaloid shark, Trigonognathus kabeyai, from the Hawaiian Islands. Pacific Science, 54(4), 389–394.