The seven recognized, extant species in this genus are: •
Bathylagus andriashevi Kobyliansky, 1986 •
Bathylagus antarcticus Günther, 1878 (Antarctic deepsea smelt) •
Bathylagus euryops Goode &
T. H. Bean, 1896 (goiter blacksmelt) •
Bathylagus gracilis Lönnberg, 1905 •
Bathylagus niger Kobyliansky, 2006 •
Bathylagus pacificus C. H. Gilbert, 1890 (slender blacksmelt) •
Bathylagus tenuis Kobyliansky, 1986 The oldest fossil species in this genus known from skeletal remains are from the
Miocene. These include
Bathylagus angelensis, whose remains are widespread across
Southern California (
Monterey Formation and
Modelo Formation), as well as
B. sencta,
B. obesa, and
B. toyohamaensis from Japan. These specimens are all known from formations that were formerly deposited in deep-sea environments, before being dramatically
uplifted to the surface by geological activity. However, tentative fossil
otoliths are also known from the
Late Cretaceous (
Maastrichtian) of the United States. ==References==