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A systematic revision of the Hemilepidotinae, a subfamily of cottid fishes Peden, Alexander Edward


An evaluation is made of the validity, phylogeny, zoogeography, ecology and taxonomy of each named species of the Hemilepidotinae. Hemilepidotus spinosus represents the most generalized line of differentiation within the Hemilepidotinae and belongs to the monotypic subgenus Galycilepidotus. H. papilio is the most modified line which belongs to the monotypic subgenus Melletes. The remaining four species are in the subgenus Hemilepidotus of which H. hemilepidotus is most generalized. All species are readily identifiable down to sizes of 16 or 17 mm. The generalized species of the Hemilepidotinae are found towards the eastern part of the range in the North Pacific Ocean, while the most modified species are found towards the west. The pelagic larvae and postlarvae drift with ocean currents which are probably the most significant means of dispersal for each species. The origin of the genus Hemilepidotus was probably in the eastern North Pacific Ocean. The modified species probably arose from westward invasions of the ancestral stock into the western North Pacific Ocean. The westward ocean current across the Aleutian Islands provides a oneway flow of larvae and postlarvae. The generalized species in the east have tended to spread west across this bridge but the most modified species in the west do not appear to have dispersed back against this current system. All species of the Hemilepidotinae are geographically sympatric with their most allied form and appear to have ecological and biological differences as well as morphological differences.

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