A Taxonomic Revision of the Sternoptychid Genus Polyipnus (Teleostei: Stomiiformes) with an Analysis of Phylogenetic Relationships

Thc benthopelagic fish genus Polyipnus (Family Sternoptychidae Günther) is taxonomically revised and the phylogenetic relationships of the species investigated. Examination of specimens from most major world collections leads to recognition of 30 species for which a key is provided. New species are described from the South China Sea, off the northwestern coast of Australia, the Andaman Sea (eastern Indian Ocean), the western Indian Ocean off Kenya, and the western North Atlantic. A study of phylogenetic relationships, based on mainly osteology and photophores, resulted in a well-resolved phylogeny. Monophyly of the genus and four species groups is indicated; species complexes of earlier authors, not defined on the basis of shared, derived characters, are abandoned. Species that were previously members of the laternarus species complex do not constitute a monophyletic group and are now placed in the asteroides and omphus species groups with their respective closest relatives. The remaining meteori and spinosus groups contain species previously referred to the asteroides and spinosus complexes. Many new records are reported for most previously recognized species. Polyipnus meteori and P. omphus which were previously thought endemic to the western Indian Ocean are found to be widespread in the Indo-Pacific. Most species distributions remain limited even with the advent of the new material.