elopomorph

Elopomorph is a term used in ichthyology to designate a member of the superorder Elopomorpha, a major clade within the ray-finned fishes (teleosts). Elopomorpha includes several orders, most notably Anguilliformes (eels) and Elopiformes (tarpons and their relatives). A defining feature of elopomorphs is the leptocephalus larval form, a transparent, leaf-shaped or ribbon-like larva that can persist for an extended period before metamorphosis into juveniles or adults. This larval stage is a distinctive and widely recognized attribute of the group.

Elopomorphs are primarily marine and estuarine. Eels (Anguilliformes) are famous for migratory life cycles that involve long oceanic journeys between spawning areas and freshwater or brackish environments where juveniles grow. Tarpons and their relatives (Elopiformes) inhabit warm coastal waters and often occupy nearshore and estuarine habitats. The group as a whole shows diversity in habitat and life history, but the leptocephalus larva remains a unifying trait.

In terms of classification, Elopomorpha is regarded as one of the major teleost superorders and is considered, in many phylogenetic analyses, to be an early-diverging lineage within Teleostei. The exact composition of orders within Elopomorpha has varied with successive revisions of fish taxonomy, but Anguilliformes and Elopiformes are the core groups traditionally associated with the clade.

Notable members include the true eels of Anguilliformes and the tarpons of Elopiformes.