Phylogenetic analysis using rDNA reveals polyphyly of Oplophoridae (Decapoda : Caridea)

Molecular phylogenetic analysis on nine of the ten genera in the caridean family Oplophoridae Dana, 1852, as well as 14 other caridean families using mitochondrial 16S and nuclear 18S rRNA genes, does not support the monophyletic status of Oplophoridae. Two disparate groups of oplophorids are revealed, with different morphological characters and ecology. It is proposed that the family Oplophoridae is restricted to the three genera Oplophorus, Systellaspis and Janicella. These three genera tend to be distributed in shallower water than the other oplophorid genera, and can also be distinguished from them by certain morphological characters. They have a thicker integument, superficial cuticular photophores and larger eyes, and the molar process of their mandibles is greatly reduced or bears a deep channel. The family Acanthephyridae Bate, 1888 is resurrected for the other seven genera, which are generally distributed in deeper water and are characterised by red soft integument, no cuticular photophores, smaller eyes and well-developed molar process of the mandibles without a deep channel. The relationships between these two families and other caridean families could not be clearly resolved in this study.