TL;DR: A new genus and species of cardinalfish (Family Apogonidae) is described from material collected at the Comoro, Fiji, and Hawaiian islands and differs externally from Rhabdamia in having one to three strong spines on the preopercular edge.
Abstract: Lachneratus phasmaticus, a new genus and species of cardinalfish (Family Apogonidae), is described from material collected at the Comoro, Fiji, and Hawaiian islands. The new genus is most similar to Rhabdamia Weber based on skeletal similarities, enlarged teeth, relatively smooth preopercular edges and deciduous cycloid scales. Lachneratus differs externally from Rhabdamia in having one to three strong spines on the preopercular edge (none in Rhabdamia), 12 or more dorsal-fin rays (11 or less in Rhabdamia). A key is provided to identify 19 recognized genera of the subfamily Apogoninae, based on external characteristics.