Three-dimensional anatomy of the early Eocene Whitephippus (Teleostei: Lampriformes) documents parallel conquests of the pelagic environment by multiple teleost lineages

The early Eocene fossil assemblage of the London Clay (Southeastern England) is a key window to the early Paleogene diversification of teleost fishes in the open ocean. Despite their three-dimensional preservation that offers unique insight into skeletal anatomy, the London Clay fossils are still poorly described for the most part. {dagger}Whitephippus tamensis is a fossil teleost from this assemblage, known by several well-preserved specimens. Based on a complete description of the known material, including previously hidden structures (braincase, hyoid and branchial arches) revealed through 3D microtomography, we reinterpret {dagger}Whitephippus as an early member of the teleost group Lampriformes. More specifically, the anatomy of {dagger}Whitephippus indicates that it is likely a member of the so-called pelagic clade including modern opahs and oarfishes. This redescription of {dagger}Whitephippus provides the earliest definitive evidence of lampriforms conquering the pelagic environment, alongside numerous other teleost lineages.