Hydrolagus

Kimberly L. Quaranta, Dominique A. Didier, Douglas J. Long & David A. Ebert, 2006, A new species of chimaeroid, Hydrolagus alphus sp. nov. (Chimaeriformes: Chimaeridae) from the Galapagos Islands., Zootaxa 1377, pp. 33-45 : 42-43

[[ Hydrolagus ]]

Key to the Eastern South Pacific species of Hydrolagus

1a. Light brown or tan coloration with numerous white markings on body.... H. mccoskeri

1b. Uniform dark brown coloration with few or no white markings on body ................... 2

2a. Body with no white markings on lateral side; snout tip pointed; slight raise in anterior portion of second dorsal fin with shallow notch medially; eyes 33.8-39.3% HDL; tail region from insertion of pelvic fins to origin of dorsal caudal fin extremely long and slender (always> 60 % BDL) ......................................................... H. macrophthalmus

2b. Body with one white spot on lateral side above pectoral fin or in abdominal region; snout tip blunt; anterior and posterior regions of second dorsal fin lobate with indented white middle region; eyes large (40.8-44.5% HDL); tail region from insertion of pelvic friends to origin of dorsal caudal fin short and stout (always <57 % BDL) ............ .......................................................................................................................... H. alphus