 The first specimens of the viper dogfish were two immature males caught off southern Japan by the bottom trawler <unk> @-@ Maru in 1986 . The first , designated as the holotype , measured 22 cm ( 8 @.@ 7 in ) long and was collected off Cape <unk> at a depth of 330 m ( 1 @,@ 080 ft ) . The second measured 37 cm ( 15 in ) long and was collected off <unk> , Tokushima at a depth of 360 m ( 1 @,@ 180 ft ) . The shark was described as a new species and genus by University of Tokyo researchers Kenji Mochizuki and Fumio Ohe in a 1990 article for the Japanese Journal of Ichthyology . They gave it the name Trigonognathus <unk> ; the generic name is derived from the Greek <unk> ( " triangle " ) and <unk> ( " jaw " ) , while the specific name honors Hiromichi <unk> , the captain of the <unk> @-@ Maru . 
