Abstract:The widely distributed deep-sea caridean shrimp Heterocarpus gibbosus Bate, 1888 was previously believed to exhibit considerable variations in the development of the basal rostral crest. Based on the comparison of abundant material from the western Pacific, combined with a molecular genetic analysis using partial sequences of the mitochondrial COI and 16S rRNA genes, three distinct species could be recognized. The true H. gibbosus has a moderately high basal rostral crest and appears to have a more eastern distribution from the South China Sea to the Indian Ocean. Both forms with a very low or very high basal rostral crest are currently undescribed and mainly distributed along the western coast of the Pacific from Japan to Fiji. The low basal rostral crest form, H. abulbus sp. nov., is unique in the genus by lacking a distinct abdominal boss and appears to be restricted to Japan, Taiwan and NE Philippines. The very high basal rostral crest form, H. corona sp. nov., occurs in the western Pacific down to NW Australia.